The Journal of Comparative Psychology (JCP): A Network Analysis of 
the Status of Comparative Psychology 
 
 
 
Daniel Lahham 
 
 
 
A THESIS SUBMITTED TO 
THE FACULTY OF GRADUATE STUDIES 
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS 
FOR THE DEGREE OF 
MASTERS OF ARTS 
 
 
 
GRADUATE PROGRAM IN PSYCHOLOGY 
YORK UNIVERSITY 
TORONTO, ONTARIO 
 
 
January, 2014 
 
 
? Daniel Lahham, 2014 
 
Network Analysis of the JCP  ii 
 
 
 
Abstract 
 Comparative psychology?s relationship to various other sub-disciplines and scientific 
?movements? has been discussed by many scholars throughout its history. The majority of these 
analyses took the form of frequency counts of the different subject species used within scientific 
periodicals (Schneirla, 1946; Beach, 1950; Dukes, 1960; Lockard, 1971) and presented similar 
conclusions: rats were the most commonly researched organism and the study of learning was 
the key to understanding behavior. The most popular of these critiques was Frank Ambrose 
Beach?s ?The Snark was a Boojum? (1950). Beach argued that comparative psychology, with the 
advent of behaviorism, slowly became a discipline focused only on rat learning in mazes. Donald 
Dewsbury (1984) responded to these discussions claiming that frequency counts alone could not 
depict the success and failures of the comparative discipline. Instead, he argued that comparative 
psychology maintained a historically continuous tradition of excellence off the efforts of a small 
group of prominent comparative psychologists. In this study, I attempted to ?bridge? the gap 
between these two competing views of the comparative discipline in order to view the legitimacy 
of both claims. Using network analysis, a tool common to digital history, I investigated metadata 
(organism studied, scientist, institution) from the Journal of Comparative Psychology during the 
period of 1911 to 1950. I found that both arguments were partially correct in their assertions. 
Comparative research was being conducted by a small group of prominent scientists throughout 
the entire four-decade period on many more species other than the rat; however, the broader 
comparative discipline was heavily impacted by the influx of research on learning in rats. In both 
cases, the authors inadvertently focused solely on their own claims, and failed to recognize the 
validity of the other. 
 
Network Analysis of the JCP  iii 
 
 
 
TABLE OF CONTENTS 
 
Abstract?????????????????????????????????????ii 
Table of Contents???????????????????????????????......iii 
List of Tables??????????????????????????????????..iv 
List of Figures?..????????????????????????????????...v 
 
Introduction???????.????????????????????????????.1 
 [Introduction]?????????????.??????????????????..1 
 [Historiography]?.?????????????????????????????.6 
 [Method]?????????????????????????????????...9 
 
Chapter One: [First Generation of Psychobiology]..??????????????????..19 
 
Chapter Two: [Second Generation of Psychobiology]?????????????????...60 
  
Chapter Three: [Neo-Behaviorism].???.?????????????.?????????88 
 
Conclusion???????????????????????????????????...137 
 
Bibliography???????????????????????????????????.146 
 
Appendices???????????????????????????????????..155 
 Appendix A: [Tables]?????.??????????????????????...155 
  
  
Network Analysis of the JCP  iv 
 
 
 
LIST OF TABLES 
 
Table 1: [Organisms (1911-1950)]??????????????????????..155 
 
Table 2: [Scientists (1911-1950)]..??????????????????????..155 
 
Table 3: [Organisms (1911-1930)]?...????????????????????...156 
 
Table 4: [Organisms (1931-1950)]?..?????????????????????156 
 
Table 5: [Institutions (1911-1950)]??????????????????????..157 
 
Network Analysis of the JCP  v 
 
 
 
LIST OF FIGURES 
 
Figure 1: [Scientist ? Organism (1911-1950) ? First Gen.]????????????....39 
 
Figure 2: [Scientist ? Organism (1911-1930) ? First Gen.]???????????.?...43 
 
Figure 3: [Scientist ? Organism (1931-1950) ? First Gen.]????????????....45 
 
Figure 4: [Institution ? Organism (1911-1950)]?????????????????....49 
 
Figure 5: [Institution ? Organism (1911-1930)]?????????????????....51 
 
Figure 6: [Institution ? Organism (1931-1950)]?????????????????....55 
 
Figure 7: [Scientist ? Organism (1911-1950) ? New Gen.]????????????....73 
  
Figure 8: [Scientist ? Organism (1911-1930) ? New Gen.]???????????.?...75 
 
Figure 9: [Scientist ? Organism (1911-1950) ? New Gen.]????????????....77 
 
Figure 10: [Scientist ? Organism (1920-1950)].????????????????.?..93 
 
Figure 11: [Institution ? Organism (1920-1950)]?????????????????..94 
 
Figure 12: [Scientist ? Organism (1920-1929)]?..????????????????..97 
 
Figure 13: [Scientist ? Organism (1920-1929)]?????????????????....98 
 
Figure 14: [Scientist ? Organism (1920-1929)]??????????????..???..99 
 
Figure 15: [Scientist ? Organism (1920-1950) ? Hull & Tolman].??????????..102 
 
Figure 16: [Scientist ? Organism (1920-1950) ? Top Rat Researchers]??.?????..109 
 
Figure 17: [Scientist ? Organism (1920-1950) ? Rat Researchers Circled]??????..114 
 
Figure 18: [Institution ? Organism (1920-1950) Rat Research Centers]???..????.122 
 
 
Network Analysis of the JCP  1 
 
Introduction 
On September 7, 1949, Frank A. Beach presided over Division 3 of the American 
Psychology Association ? the Division of Experimental Psychology ? and delivered an address 
as co-president.1Beach calculated the proportions of different organisms used as subjects in 
studies published in the Journal of Comparative Psychology and the two journals from which it 
had descended: Journal of Animal Behavior and Psychobiology. Beach argued that psychologists 
were basing their studies disproportionately on the rat in comparison to other organisms in 
comparative psychology and the entire psychological discipline at large2. He argued that for a 
discipline to be truly comparative, a wide variety of organisms must be used. The rat may indeed 
still be used but in addition to other mammals, vertebrates, and invertebrates; not the heavy 
concentration on a single organism that has historically occurred. Since comparative psychology 
sought to compare organisms, Beach questioned how one could claim to be a comparative 
psychologist and have one species predominate to such a degree. He further declared that this 
over-concentration had caused comparative psychology to ?suddenly and softly vanish away? 
(Beach, 1950, p. 115).   
Although offered comically and metaphorically, Beach?s address (and later article), 
entitled ?The Snark was a Boojum? affected the discipline beyond just the article itself: it set off 
a series of studies on the different organisms used as test species in the Journal of Comparative 
Psychology. Indeed, every decade since the address, at least one study has been conducted that 
?took another look at the Snark? in order to determine the rat?s rise as a subject species (Dukes, 
                                                 
1 Beach was originally elected as President by Division 6 ? Division of Physiological and Comparative 
Psychology. After the merger between Division 6 and Division 3 in 1948 -1949, Beach joined W.J. Brogden as co-
presidents of Division 3 (Dewsbury, 1996). 
2 The reasons the rat became the standard laboratory are many and will not be discussed here.  
 
Network Analysis of the JCP  2 
 
 
 
1960; Lockard, 1971; Porter, Johnson & Granger, 1981; Grossett & Poling, 1982; Adkins-Regan, 
1990; Dewsbury, 1998; Shettleworth, 2009). However, although Beach?s concern has received 
the most attention, he was not the first to draw attention to this rat phenomenon; Theodore 
Christian Schneirla originally signaled this overuse of the rat in 1946. Indeed, Schneirla and 
Beach were close colleagues at the American Museum of Natural History during the 1940s 
(Dewsbury, 1984). 
This thesis is not an attempt to ?revisit? this Snark phenomenon, nor is it an attempt to 
explain why the rat (or any other species) came to be such a prolific laboratory animal. This has 
been done very well already by Cheryl Logan (1999; 2005). Furthermore, this thesis is not a 
chronological history on comparative psychology. Donald Dewsbury has written an exhaustive 
history of the discipline and remains one of the authoritative voices on comparative psychology. 
Instead, in this study, I chose to examine the historical claims made about the successes and 
failures of comparative psychology as a discipline, and its relationship with various other 
subdisciplines and scientific ?movements.? In particular, I attempted to determine how 
comparative psychology could have disappeared after the 1920s (Beach, 1950) whilst 
simultaneously prospering in the 1930s (Dewsbury, 1984).3 To explore these contradictory 
claims, and reconcile how both could exist simultaneously, I went beyond the assessment of 
model organisms alone, and included the organisms? experimental relationships with the 
researchers and institutions that studied them. 
Similar to the other ?Snark? articles, I extracted my data (organisms, scientists, and 
institutions) from articles in the Journal of Comparative Psychology. Although this journal did 
not encompass the entirety of comparative psychology?s breadth, it was one, significant marker 
of the field. Since I had access to every article published in the JCP, I utilized a ?digital? 
                                                 
3 Both Beach?s and Dewsbury?s claim were unpacked later in the thesis.  
Network Analysis of the JCP  3 
 
 
 
approach for this project. The particular digital approach I employed was that of a network 
visualization that depicted the connections between organisms and the researchers and 
institutions that studied them. Through the structures of these networks, I argued that the claims 
made by Beach in 1950 and Dewsbury in 1984 about the status of comparative psychology as a 
discipline were both correct at root, but flawed insofar as they both inadvertently failed to 
recognize the validity of each other?s argument.  
There was an obvious ?data gap? between these two studies, which was likely a 
contributing factor to their opposite stances. Beach and Dewsbury used only partial runs of 
journals because they did not have the technology now available to handle large bodies of data. 
To bridge this gap, I included all the data in the specified time period, and I have expanded its 
breadth to include not only the organisms studied, but also the scientists and institutions that 
studied them. This allowed me to expand upon Beach?s data ? which included only odd 
numbered volumes, and focused solely on the frequencies of organism use and topics under 
study. Moreover, by expanding my data to include scientists and institutions in the study, I was 
able to use these pieces of data to dig deeper into the historical literature, bringing me closer to 
Dewsbury?s extensive qualitative analysis. Thus, my study merged the quantitative (Beach) with 
the qualitative (Dewsbury). 
As was mentioned previously, Beach (1950) contended that comparative psychology 
disappeared post 1920s, only to be replaced by behaviorism. Schneirla (1946; 1952) similarly 
argued Beach?s point, asking the question, ?Have We a Comparative Psychology?? in his critical 
evaluation of the discipline (Schneirla, 1952).Dewsbury (1984), on the other hand, was much 
more optimistic in his view of the discipline, claiming that the discipline prospered in a time 
when most others saw it on the decline. A reason for the discrepancy between these claims 
Network Analysis of the JCP  4 
 
 
 
stemmed from how each author assessed the discipline: Beach and Schneirla interpreted the 
discipline by way of the most studied organisms (rats); and Dewsbury appraised comparative 
psychology through key events (conferences, publications, etc.) and prolific comparative 
psychologists (Robert Yerkes, Karl Lashley, Calvin Stone, Harry Harlow, and not least of all 
Beach and Schneirla).  
To demonstrate the accuracy of both claims on the status of comparative psychology, I 
assessed the influence of two competing, yet similar behavioral approaches: psychobiology and 
neo-behaviorism. Both approaches indicated the shift in American psychology from the study of 
internal mental states to the study of overt behaviors at the turn of the century. Moreover, both 
approaches directly connected to the arguments of Dewsbury, and that of Beach and Schneirla. 
Dewsbury argued that comparative psychology was maintained and prospered from of the efforts 
of a handful of prolific comparative psychologists. Since there is no consensus on what, 
precisely, identifies a comparative psychologist (Dewsbury, 1984), I likened Dewsbury?s 
?comparative psychologists? to the tag of ?psychobiologist.?Two features bound the terms 
?comparative psychologist? and ?psychobiologist?:4 the study of behavior through the lenses of 
psychology and/or biology; and the conducting of research outside of the behavioristic 
framework. Indeed, even Dewsbury himself used the two terms interchangeably on the same 
individuals (Robert Yerkes and Karl Lashley were both comparative psychologists and 
psychobiologists) (Dewsbury, 1984; 1991; 2002). Thus, I used the title ?comparative 
psychobiologist? to describe the individuals that Dewsbury claimed maintained the comparative 
discipline throughout the four decade period. I assessed these comparative psychobiologists at 
                                                 
4 ?Psychobiology? should not be confused with ?biopsychology.? Whereas ?psychobiology? is focused on the 
biological basis of behavior, ?biopsychology? is a branch of psychology that emphasis biological and physiological 
aspects (Dewsbury, 1991). 
Network Analysis of the JCP  5 
 
 
 
the individual and institutional level to investigate whether or not they were indeed as prolific (in 
terms of quantity and quality) as Dewsbury had argued. 
Citing the disproportionate use of rats as subject animals (the model organism of choice 
in neo-behaviorism),5 and the rise in popularity of the maze learning studies akin to neo-
behaviorism, Beach and Schneirla purported that behavioristic theory essentially replaced 
comparative psychology post 1920s. As such, I sought to determine the influence of neo-
behaviorism in the JCP to explore the claim that it ?replaced? comparative research. To 
accomplish this, I examined the most historically prolific neo-behaviorists, and the researchers 
and institutions most closely connected to the rat (measured in terms of quantity).  
In order to determine the influences of both psychobiology and neo-behaviorism, the 
thesis comprised of three chapters. The first and second chapters covered the period from 1911 to 
1950, and focused on the influence of the prominent comparative psychobiologists, indicated by 
Dewsbury, within the newly established Journal of Comparative Psychology. Moreover, the two 
chapters examined this era diachronically, breaking the time frame into two distinct periods, 
1911 to 1930 and 1931 to 1950, in order to elucidate the different generations of comparative 
psychobiologists. The first chapter began by reviewing the literature on early comparative 
psychology in order to establish the initial purpose of the discipline of comparative psychology. 
Next, the first chapter examined the ?first generation? of comparative psychobiologists. The 
second chapter, then, investigated the ?new generation? of comparative psychobiologists. The 
third and final chapter assessed the time frame from 1920 to 1950 in a synchronic fashion, and 
examined the influence of neo-behaviorism in the JCP. Although this time frame was seemingly 
identical to chapter one and two, each chapter examined different sections within the overall 
                                                 
5 The term ?neo-behaviorism? refers to the reformulations in the 1920s, 30s, and 40s, of Watson?s Behaviorism of 
the 1910s. 
Network Analysis of the JCP  6 
 
 
 
network. For example, whereas the networks in chapters one and two placed the emphasis on the 
number of organisms studied, the networks in chapter two placed the emphasis on number of 
studies conducted. In chapters one, two, and three, I utilized two different network constructions: 
the first network displayed the relationship between organisms and authors; and the second 
network portrayed the relationship between organisms and institutions. Throughout these 
chapters, I will show that Dewsbury was correct in claiming that comparative psychology (via 
psychobiology) was maintained by a handful of prominent individuals whilst also demonstrating 
that through the influence of neo-behaviorism (via the rat) in the JCP, Beach?s assertion that 
behaviorism replaced comparative psychology, although extreme in its proclamation, was also 
correct. 
Historiography 
Historians have often taken different approaches to writing the history of comparative 
psychology and the relationships between scientists and organisms. Moreover, each historian has 
their own distinct interpretation of the historical events they chronicle. For Beach (1950), the 
history of comparative psychology was a tragedy: comparative psychologists became too 
enthralled with the rat as a laboratory animal and stopped ?comparing? organisms. He appealed 
to the comparative psychologists of his time, imploring them not to do away with the rat, but to 
diversify the laboratory organisms they used. Beach went so far as to claim that an 
overdependence on the rat and learning studies had caused comparative psychology to disappear 
only to be replaced by behaviorism. In order to make these claims, he collected his data from 
odd-numbered volumes of the Journal of Animal Behavior, Psychobiology, and the Journal of 
Comparative Psychology. Beach was interested in which organisms were being studied and in 
the general topics of the research (e,g., learning, development, reproduction, etc.), of which he 
Network Analysis of the JCP  7 
 
 
 
had seven categories. He presented the percentages of articles that used each organism in 
specified time frames, and the percentage of articles focused on each of his seven topic 
categories. For Beach, he was not so much concerned with the scientist, as he was with the 
organisms. Many other scholars and historians have echoed Beach?s sentiment and methodology. 
Porter, Johnson, and Granger (1981) continued Beach?s study, and examined the proportions of 
organisms being used in the Journal of Comparative and Physiological Psychology from 1961 to 
1976. They reported a similar overdependence on the rat. Beach and Porter et al. both interpreted 
the history of comparative work through the lens of the most studied organism: the rat.6 
Beach?s 1950 paper was an extension of Schneirla?s (1946) study in which he analyzed 
the articles in the Journal of Animal Behavior (JAB)from 1911-1917 and the articles in the JCP 
from 1938-1941 (Schneirla, 1946). Schneirla noted some striking findings in the data. The most 
dramatic finding was the increase in the percentage of articles with rats as subject species that 
went from 19% in the JAB to 66% in the JCP. Schneirla also showed that the percentage of 
studies on invertebrates dropped from 33% in the JAB to 5% in the JCP. Using this data, 
Schneirla claimed that comparative psychology was not very comparative at all and had changed 
with the advent of behaviorism. However, included in his analysis was a caveat that has oft-been 
overlooked by researchers conducting similar research (Schneirla, 1946; Dewsbury, 1984). 
Schneirla warned that the JAB was a highly interdisciplinary journal, and a large number of the 
studies were contributed by biologists. He further asserted that the majority of early research on 
the problems of instincts were conducted by zoologists; psychologists were more commonly 
studying learning and sensory systems (Schneirla, 1946).  
 Dewsbury (1984) took a different approach and interpretation of the history of 
comparative psychology: he chronicled the sub-discipline?s history in its entirety, not focusing 
                                                 
6 Many others have continued this trend: Adkins-Regan, 1990; Dewsbury, 1998; Shettleworth, 2009. 
Network Analysis of the JCP  8 
 
 
 
solely on its flagship journal. Moreover, he did not conduct the frequency analyses that 
Schneirla, Beach, and other ?Snark? scholars had done. For him, comparative psychology was 
not the tragedy that Beach and others had imagined. Instead, Dewsbury saw a new field in a 
fledging discipline striving to find and sustain success. He interpreted the history of comparative 
psychology by focusing on the organisms being studied, the important figures that helped build 
the field, and the major events that took place in the time period he covers. Unlike Beach, 
Dewsbury emphasized both the scientist and the organism. Moreover, Dewsbury broke down his 
chapters by each successive decade. His data was not explicitly displayed as it had been in 
Beach?s ?The Snark was a Boojum,? but was woven into the story he told. He did not write of 
proportions of certain organisms or percentages of certain types of studies. Instead, he drew 
attention towards certain landmark events in the discipline. Describing Dewsbury as an optimist 
would not be an overstatement. The periods in which many viewed comparative psychology as 
being on the decline, Dewsbury subscribed to an opposing position. For instance, Misiak and 
Sexton (1966) viewed the 1930s as a period of progressive decline in comparative psychology 
due to the rise of clinical psychology and the increasing specializations of other psychological 
fields. Dewsbury, on the other hand, viewed it ?as an outstanding decade in comparative 
psychology? (1984, p. 99). He argued that a new generation of comparative psychologists were 
produced that were some of the most prominent psychologists of the day. The 1940s had also 
been seen by earlier authors as a period of decline in comparative psychology (Schneirla, 1946; 
Scott, 1973). Once again, Dewsbury rejected this, arguing that ?the vigor that was generated in 
the 1930s was sustained in the 1940s? (1984, p. 117), mostly through the continued productivity 
of the ?new generation? of comparative psychologists. Although there were fewer newer faces in 
the 1940s, the established comparative psychologists were as active as ever. Dewsbury 
Network Analysis of the JCP  9 
 
 
 
conducted a masterful synthesis of the key events, institutions, and figures in comparative 
psychology in the twentieth century, going beyond the JCP. Few scholars have gone to the 
lengths that Dewsbury did in his account of the discipline.   
Method 
Since this project dealt with a large amount of data (1911-1950), I chose to use digital 
methods that provide the network visualizations, which, when coupled with traditional methods, 
provide a powerful new interpretation or understand of the topic. A network is an example of one 
form of these visualizations.  
With initiatives in place to digitize large bodies of text, the number of sources available 
to historians has greatly increased (Rosenzweig, 2003). These large databases were the impetus 
for the development of new digital methods.  One of the most appealing aspects of digital history 
is the sheer number of sources that can be included in a single analysis. Computational analysis 
allows one to analyze hundreds or even thousands of sources that would otherwise be impossible 
to examine closely even over the course of a single individual?s entire career. These 
computational methods often include computing word frequencies and carrying out various kinds 
of text mining. The present study benefited from these advantages in two ways: accessibility and 
size of database. The journal from which the data was drawn has been digitized and is available 
via the scholarly database PsycInfo. Thus, access to the primary literature was straightforward 
and efficient. The journals under consideration published over 2000 articles in the relevant time 
range, from which the metadata was retrieved. In order to analyze this ?big data,? computational 
methods were necessary.  
Many scholars have been moving towards answering historical questions by using digital 
tools that mobilize large quantities of data. Indeed, historians of science have shown an interest 
Network Analysis of the JCP  10 
 
 
 
in developing new approaches that incorporate both close reading, in its traditional sense, and 
?distant reading,? that is to say, the aggregation and analysis of large amounts of data (Moretti, 
2005), which are now made possible with digital historical methods. The exponential growth of 
physics in post-Cold War America had led David Kaiser (2012) to embrace and advocate change 
in historical methods. Kaiser argues that this exponential growth has robbed the historian the 
privilege of solely relying on traditional tools of inquiry such as ?close-focus case studies, deep 
archival excavations, [and] microhistories? (Kaiser, 2012, p. 276). For him, ?these tools of 
inquiry seem to be no match for the brute fact of exponential growth ? the extraordinary 
expansion of people, places, and papers that has marked the scientific at least since World War 
II? (p. 276). Kaiser?s solution was a series of quantitative methods that determined the number of 
PhDs received and the size and number of journals, making clear patterns in isolated case 
studies, and making visible questions that can lead to close, archival research.  
Extracting large amount of data from open access databases ? which I have done in this 
thesis ? is not a new concept. A project conducted by Jane Maienschein and Manfred Laubichler 
(2010) utilized the open access database, PubMed, as a digital archive providing insight into the 
history of developmental biology. 
As is the case with most methodologies, there are limitations to accompany the many 
advantages. In the case of digital history methods, the limitations have been well documented by 
the same scholars that advocate its use. Caroline Winterer (2012) analyzed correspondence 
networks using Geographic Information System (GIS) mapping ? a system to analyze, manage 
and present geographical data ? in order to determine America?s place in the Republic of Letters 
? the long distance community of intellectuals in the 17th century. However, Winterer proposes 
the caveat that ?digitizing humanistic data forces black-and-white answers onto the kinds of 
Network Analysis of the JCP  11 
 
 
 
grey-area questions that historians usually delight in tackling? (Winterer, 2012, p. 598). 
Although this may sometimes be the case, I would argue that the networks continuous spatial 
layout allows for much finer investigations of the range of greys than one would be able to 
navigate with mere words. In any case, these limitations outlined by Winterer need not be 
debilitating as long as we keep in mind that the visualization alone does not provide 
instantaneous interpretative insights, but rather, is a guiding tool that informs the historian?s 
judgment. The visualizations used in this project were created by using important pieces of 
metadata coded from the articles and relied heavily on uncovering hidden and salient 
relationships through the study of the relevant literature (Pettit, Serykh, and Green, 
forthcoming/2015). 
Networks and Data 
The data for this project was collected by recording several important pieces of metadata 
from each substantive7 article in the Journal of Comparative Psychology: year, organism of 
choice, author(s), and institutional affiliation. The entire run of the journal was available from 
the scholarly database called PsycInfo. From each article, the year of publication, the type of 
organism used in the study, the name of the author(s) of the study, and author?s institutional 
affiliation were recorded, by hand, in an Excel spreadsheet. The spreadsheet was then imported 
into a program called Gephi that produces network images from datasets.  
A network graph is made up of two classes of components: nodes and edges. Nodes 
represent ?actors?(which can be nonhuman entities such as animals or institutions). Edges 
connect two nodes and represent particular kinds of relationships between those particular actors 
(e.g., node x used node y in research, x published y, etc.). For the present study, the nodes 
                                                 
7 In this case, a substantive article refers to an original empirical article. Reviews, notes, obituaries, and 
theoretical articles are excluded. 
Network Analysis of the JCP  12 
 
 
 
represented the organism used, and either the first-author of the publication or the institution 
affiliated with the publication, depending on the particular kind of network. The edges 
connecting these nodes to represent two distinct relationships: either that between the author and 
organism, or that between the institution and the organism. Edges can be directed or undirected. 
Direction conceptualizes the overall network. If a relationship is considered directed, it purports 
that one node is acting upon another node in some way. For example, a relationship would be 
directed if one individual sends a letter to another. An undirected network assumes that 
directionality is unimportant in that particular relationship. Edges can also be weighted; weighted 
records something quantitative about the relationship between two nodes. For this particular 
project, the edges were weighted based on the number of publications a particular author had 
using a particular organism or the number of publications an institution had using a particular 
organism.    
In this thesis, I used a social network software called Gephi. Gephi reads its data from a 
CSV spreadsheet and can easily export back to a spreadsheet. Not only can Gephi provide 
aesthetically pleasing network visualizations, but it also provides informative measures for 
understanding the structure of the network. One of these measures is the idea of centrality within 
the network. Freeman (1979) classified three forms of centrality: degree, betweenness, and 
closeness. Degree centrality measures the number of edges that are connected to that particular 
node. This indicates the overall connectivity of that node within the network, and in my case, 
makes salient the most prolific authors, institutions, or organisms. A node?s degree is directly 
related to its visibility and importance within the network; the higher the degree, the more visible 
and important the node. The problem with degree, however, is that an edge that represents a 
single article by an author about a given organism is indistinguishable from one that represents 
Network Analysis of the JCP  13 
 
 
 
five articles by one author about a given organism, unless the difference is represented by 
something we call ?weight? ? the thickness of the edge in the network. To resolve this problem, 
a second degree measure is used that measures the total weight of the links coming into a 
particular node. This measure, called ?weighted degree,? was used to determine the most prolific 
authors, institutions, and organisms in terms of output. Betweenness measures how often a 
particular node appears on shortest paths between every pair of nodes in the network (Brandes, 
2001). It makes visible the nodes that serve as mediators between different parts of the network 
and is independent of a nodes degree centrality. This measure would be particularly fruitful in 
determining the most active employee in a workplace. Closeness centrality measures the average 
distance from a given node to all other nodes in the network (Brandes, 2001). This type of 
centrality would be most useful in analyzing correspondence networks. Because I am mostly 
concerned with which actors (nodes) were the most influential within the overall network, only 
degree centrality was used in my project (Pettit et al., forthcoming/2015). Although degree 
centrality is the simplest measure, it is often the most useful. Apart from degree centrality, I also 
used a node?s position in the network, often referred to as the spatial layout of the network, to 
assess the relationship between two nodes. The spatial layout of particular nodes in the network 
is highly dependent on both degree and weighted degree. How far a node is positioned from the 
center of the network depends on how many distinct connections it makes. The more connections 
a node makes, the more integral they are to the overall network structure. Moreover, weighted 
degree influences the force or strength a particular node has over nearby nodes.  
Two separate networks were created; one that covered the data from 1911 to 1950; and 
another that covered the period of 1920 to 1950. Moreover, the networks were constructed in two 
Network Analysis of the JCP  14 
 
 
 
different ways: an author based network that represents an author-organism dyad, and an 
institution based network representing an institution-organism dyad. 
Source (JCP) 
 The data was taken from the Journal of Comparative Psychology (JCP) from the period 
of 1911 to 1950. The data consisted, specifically, of organisms, authors, and institutions. This is 
the current title of the journal (since 1983), but it has operated under three other titles ? Journal 
of Animal Behavior (JAB), Psychobiology (PSB), and Journal of Comparative and Physiological 
Psychology (JCPP) (Burkhardt, Jr., 1987; [Cover], 1947). The journal originally began as the 
JAB and ran from 1911 to 1916. After the journal could not financially sustain itself, it was 
dropped and effectively replaced by PSB in 1917. PSB would not last long, printing only two 
volumes in 1917/18 and 1920, before changing names to the JCP. The JCP was established in 
1921 as the combination of the interests of the JAB and the PSB. The JCP operated under the 
editorship of Knight Dunlap until 1943, when one of his colleagues, Roy M. Dorcus, took over 
editorial duties. Dorcus held editorship until 1947, when Calvin Perry Stone became editor and 
the journal?s name changed to the JCPP. In 1983, the journal split into Behavioral Neuroscience 
and the reinstated JCP.  
Journal of Animal Behavior 
 The establishment of this journal owed much to the diligent work of Robert Yerkes. 
Indeed, the JAB is often considered to be Yerkes? journal (Burkhardt, Jr., 1987). At the turn of 
the century, the study of animal behavior was gaining momentum. Yerkes, who established the 
animal psychology laboratory at Harvard and arranged a book series focused on animal behavior 
with the Macmillan Company, grew impatient with the lack of a journal specifically dedicated to 
publish animal work. He sought the advice of the zoologist, Herbert Spencer Jennings, about 
Network Analysis of the JCP  15 
 
 
 
establishing such a journal in 1903, a year after he graduated with his doctorate. Jennings 
suggested that the Carnegie Institute of Washington might fund the endeavor, but it appeared that 
Carnegie had other intentions with their money (Burkhardt, Jr., 1987). Yerkes was forced to 
move in a different direction, becoming an editor for the Journal of Comparative Neurology 
(JCN) in 1904. The JCN was founded by C.L. Herrick in 1891 as ?a quarterly periodical devoted 
to the comparative study of the nervous system (Herrick, 1891). Yerkes joined the likes of 
Herrick, his brother C.J. Herrick, and O.S. Strong, and was put in charge of all work published 
by the journal in comparative psychology and animal behavior; topics that the journal newly 
adopted. This change in the journal?s scope was indicated by the change of its title to the Journal 
of Comparative Neurology and Psychology (JCNP) in 1904.8 Unfortunately, most journals were 
not self-supporting enterprises at this time and the new JCNP was in financial peril. Yerkes had 
made many attempts to solve the issue, but faced too many impediments (Burkhardt, Jr., 1987). 
The journal needed more subscriptions but faced heavy competition from the Biological Bulletin 
and the newly established Journal of Experimental Zoology (JEZ) in 1904. By 1906, Jennings 
and many other collaborators of the JCNP had felt that animal behavior work was better suited 
for the JEZ. Yet, the JEZ suffered the same financial difficulties as the JCNP. Both would be 
purchased by the Wistar Institute of Anatomy and Biology in Philadelphia in 1907 along with the 
Journal of Morphology, the American Journal of Anatomy, and the Anatomical Record. Jennings 
and Yerkes saw this centralization as a chance to better concentrate materials on animal 
behavior; unfortunately, this hope was not realized, and both men began looking for another way 
of concentrating animal research. Although Jennings was full of doubt that an animal behavior 
journal could self-support, Yerkes pursued the matter in earnest in the following years 
(Burkhardt, 1987). 
                                                 
8 For a more detailed account of the reasons and justifications for this change, see Burkhardt, Jr., 1987. 
Network Analysis of the JCP  16 
 
 
 
By January, 1910, plans were in place for a new journal, and Yerkes and Watson had 
begun the process of selecting an editorial board. Although many names were suggested, the 
editorial board ultimately consisted of prominent zoologists S.J. Holmes (Wisconsin), Jennings 
(Johns Hopkins), and W.M. Wheeler (Harvard), and significant psychologists M. Bentley 
(Illinois), H.A. Carr (Chicago), E.L. Thorndike (Columbia), Watson (Johns Hopkins), M.F. 
Washburn (Vassar), and Yerkes (Harvard), who served as managing editor ([Cover], 1911). The 
JCNP announced the new Journal of Animal Behavior late in 1910 (Herrick, 1910). Although the 
editors of the JCNP expressed regrets that they were losing Yerkes and his two associates, 
Watson and Jennings, they wished the new journal success, and recommended that any papers 
regarding comparative psychology or animal behavior be sent to the JAB. In 1911, eight years 
after Yerkes had first expressed to Jennings the need for a journal for work on animal behavior, 
the JAB published its first issue. The JAB would soon face financial issues of its own, which led 
to its discontinuation in 1917. Yerkes had managed to keep the journal afloat through 1915 based 
on contributions from the editors themselves, but with escalating printing costs in 1916, the 
journal ran a deficit. Yerkes discussed the idea of having the Wistar Institute take over financial 
responsibility for the journal, but the initiative was fruitless. Even raising the subscription price 
from $3.00 to $5.00 was not enough to save the journal. Financial concerns were not the only 
reason the journal did not survive. The JAB rested on the efforts of Yerkes, and in 1916 and 
1917, Yerkes took on many other initiatives that occupied up much of his time. He served as 
president of the APA in 1916/1917; he organized the Army intelligence testing program during 
the war; and he chaired the Psychology Committee of the National Research Council (Burkhardt, 
Jr., 1987). 
Psychobiology 
Network Analysis of the JCP  17 
 
 
 
 In May 1917, Knight Dunlap approached Yerkes with the suggestion that the Journal of 
Animal Behavior be merged with his soon to be established periodical, Psychobiology (PSB). 
Yerkes immediately rejected the offer, claiming that it would not be advantageous to combine 
the interests of the two journals (Burkhardt, Jr., 1987). Nonetheless, PSB published its first issue 
in July 1917. It ran two volumes, one in 1917/1918, and the other in 1920. In his opening 
editorial, Dunlap said that the journal?s primary aim was ?the publication of research bearing on 
the interconnection of mental and physiological functions? which included work on 
?physiological psychology?pharmacology, physiology, anatomy, neurology and psychiatry in 
so far as the results of these investigation have explicit bearing on problems of mental life, or 
mental factors are included in the essential conditions of the investigation? (Dunlap, 1917, p. 1). 
In addition to Dunlap (Johns Hopkins), the journal?s editors were J.J. Abel (Johns Hopkins), 
W.B. Cannon (Harvard), R. Dodge (Wesleyan), S.I. Franz (Government Hospital), H.S. Jennings 
(Johns Hopkins), and G.H. Parker (Harvard). 
Journal of Comparative Psychology 
In 1921, the JCP was established, replacing both JAB and PSB (Burkhardt, Jr., 1987). 
Yerkes and Dunlap served as co-editors for this journal; although Dunlap served as managing 
editor and took primary control of the journal. Up till this point, Yerkes was still heavily 
involved with his chairmanship of the Research Information Service of the National Research 
Council. The remainder of the editorial board consisted of the amalgamation of the editors of the 
JAB and PSB. The JCP would continue publishing until its name change in 1947. 
Journal of Comparative and Physiological Psychology 
 In 1947, the JCP was renamed the Journal of Comparative and Physiological Psychology 
([Cover], 1947). Calvin P. Stone served as the new managing editor for this journal, joined by an 
Network Analysis of the JCP  18 
 
 
 
impressive list of consulting editors: F.A. Beach (Yale), C.W. Darrow (Chicago), R.M. Dorcus 
(California), H.F. Harlow (Wisconsin), W.T. Heron (Minnesota), H. Kl?ver (Chicago), K.S. 
Lashley (Yerkes Laboratories), C.T. Morgan (Johns Hopkins), E.C. Tolman (California), and 
G.R. Wendt (Rochester) ([Cover], 1947). The journal would run under this name until it split 
into Behavioral Neuroscience and the Journal of Comparative Psychology (for a second time) in 
1983. It is not well documented why the journal?s name was changed to include physiology in its 
title. According to historian Don Dewsbury, ?the field was changing and the physiological types, 
growing rapidly, felt that the name no longer was appropriate for their work? (Dewsbury, 2012, 
email correspondence). 
  
Network Analysis of the JCP  19 
 
 
 
Chapter One: First Generation of Psychobiology in the Journal of Comparative Psychology 
Determining a date that marked the beginning of comparative psychological work is a 
difficult task and a debate on its own. Dewsbury (1984) chose to begin his history with a 
prehistory dating back nearly 34 000 years. Eventually, he designated the year 1894, not as the 
beginning of comparative psychology, but as his preferred starting point. Although Dewsbury 
considers 1894 to be somewhat of an arbitrary choice, his decision was guided by important 
intellectual events of the year, some of which were: the death of von Helmholtz and Romanes; 
Margaret Floy Washburn took her PhD at Cornell under Titchener; John Dewey moved to the 
University of Chicago and M?nsterburg was at Harvard; James McKeen Cattell and James Mark 
Baldwin established the Psychological Review as an alternative outlet to the house organ The 
American Journal of Psychology; and the year 1894 saw the publication of C. Lloyd Morgan?s 
An Introduction to Comparative Psychology. Following Dewsbury, I chose 1894 as the most 
appropriate starting point for this project.  
1894-1899 
As Dewsbury aptly suggested, the year 1894 was important for the emergence of 
comparative psychology. American Psychology was preparing for the explosive growth that the 
turn of the century would bring: twenty-nine psychology laboratories had been established across 
the United States by 1894 (Garvey, 1929). In the same year, G. Stanley Hall, a staunch advocate 
for the grounding of scientific psychology in the model of Darwinian evolutionary theory, was 
serving in his sixth year as President of Clark University. Baldwin, another proponent of 
evolutionary theory in psychology, was at Princeton where the year prior he established his 
second psychological laboratory (the first was at Toronto in 1890). Baldwin later reopened the 
Johns Hopkins laboratory in 1903. One of Baldwin?s most important contributions to the study 
Network Analysis of the JCP  20 
 
 
 
of evolution, and by extension comparative psychology, was his proposal of ?organic selection? 
in 1896. This process was later dubbed the ?Baldwin effect? (Simpson, 1953). Essentially, the 
?Baldwin effect? explained the process by which a nonhereditary (acquired) trait might come to 
be hereditary without resorting to Lamarckian mechanisms. Also in 1894, Baldwin teamed up 
with James McKeen Cattell to found the Psychological Review, a journal to rival the The 
American Journal of Psychology. Baldwin and Cattell originally proposed one of two options to 
Hall: buying The American Journal of Psychology from him, or at least establishing a board of 
editors with powers to accept and reject submissions. Hall refused both options even though he 
admittedly had grown tired of the duties of an editor (Sokal, 1997). The Psychological Review 
held importance for comparative psychology, since much early comparative work was published 
in this journal. A journal dedicated solely to comparative work, however, was not established 
until the Journal of Animal Behavior (JAB) in 1911.  
The year 1894 also saw significant events in Europe that helped shape comparative 
psychology. It was in this year that Wilhelm Wundt?s Lectures on Human and Animal 
Psychology was translated by J.E.E. Creighton and E.B. Titchener and first published in English. 
Wundt described two different approaches to animal psychology: a comparative approach where 
animals (including humans) were studied for the purpose of understanding the development of 
the organic mind, and an alternative approach in which animals were studied solely for their 
utility in understanding the human mind. Not only did Wundt?s Lectures have a profound 
influence on the legitimacy of animal psychology and the method of objective behavioral 
observation, but his recognition of a purely comparative approach with no reference to its human 
relevance was an important step in establishing the field of comparative psychology (Dewsbury, 
1984).  This prompted Warden?s remark that ?even so conservative a writer as 
Network Analysis of the JCP  21 
 
 
 
Wundt?recognized the right of comparative psychology to develop a content independent of 
human reference in the same sense as zoology is independent of human morphology and 
physiology? (Warden, 1928, p. 514).  
In England, C. Lloyd Morgan?s publication of An Introduction to Comparative 
Psychology has been referred to by Dewsbury as ?the most memorable event? of 1894 
(Dewsbury, 1984, p. 45). The book outlined trial-and-error learning, ?constraints? on learning, 
and accepted the idea that perception should be viewed from the organism?s perspective. 
Morgan?s book rejected the view of Larmackian9 inheritance of acquired traits (Dewsbury, 1979; 
1984). A staunch supporter of the study of instinctual behaviors, Morgan wanted to separate 
inherited behavior from learned behavior. For him, every species has its own instinctive 
behaviors that do not have to be learned; the discussion of ?consciousness? in animals can only 
be had if the behavior cannot be explained by any other way. Indeed, Morgan?s canon states:  
In no case may we interpret an action as the outcome of the exercise of a higher psychical 
faculty, if it can be interpreted as the outcome of the exercise of one which stands lower 
in the psychological scale (Morgan, 1894, p. 53). 
Morgan would figure prominently in the coming post-World War I debates on instinct.  
 A few years later, at Clark University, Linus Kline and Willard S. Small conducted the 
first psychological tests of rats in mazes, an event that set the standard for animal psychology 
and comparative psychology in the twentieth century (Dewsbury, 1984). Kline first came to 
Clark University in 1896 to study ?zoological psychology.? Interested in what he termed home 
sickness, Kline studied homing in bees, pigeons, and chicks. Dewsbury describes Kline?s use of 
rats and mazes as a somewhat serendipitous event. Kline was working with chicks and reading 
                                                 
9 Lamarckian inheritance or Lamarckism is the process of an organism passing on a trait to its offspring that 
was acquired, not inherited. It was named after the French biologist and evolutionary theorist Jean-Baptiste Lamarck 
(1744-1829) (Sapp, 2003; Gould, 2002).   
Network Analysis of the JCP  22 
 
 
 
Morgan?s Introduction when the idea of trapping rats in small boxes to study their food 
searching behavior occurred to him. The inspiration for the use of rats came from a Clark 
colleague, biologist Colin C. Stewart, who studied the effects of alcohol, diet, and barometric 
pressure on rat behavior. By the fall of 1898, Kline had devised a study in which rats learned 
how to get food from ?mouse boxes.? On December 3, 1898, Kline undertook his first study of 
learning in rats (Dewsbury, 1984). A little over a month later, on January 9, 1899, Kline 
conducted a study on social interactions, in which two rats had to interact to secure food from a 
box.  The use of a maze, however, was the idea of Edmund C. Sanford, professor of psychology 
and founding director of the Clark psychology laboratory (Sokal, 1990). Kline described to 
Sanford ?runways [he] observed several years ago made by large feral rats to their nests under 
the porch of an old cabin? (cited in Miles, 1930, p. 331). Sanford promptly suggested to Kline 
the use of the Hampton Court maze. Kline subsequently modified the design out of an 
encyclopedia, and the first maze was constructed by Small. Small noted in his study on rat maze 
learning (Small, 1901) that the natural propensity of the rat to navigate winding passages was a 
critical reason for their decision to study rats using mazes. In terms of the first use of white rats, 
Stewart began his studies using wild, ?gray? rats before moving onto tame white rats. On his 
switch, he wrote, ?If anyone wants to know why I changed from wild gray rats to white rats in 
1895, let him work with gray rats for a year? (cited in Miles, 1930, p. 334). Stewart got his white 
rats from C.F. Hodge, a biologist specializing in neurology and physiology at Clark (Baldwin, 
1901). Around the same time, another neurologist and student of Hall?s, Henry H. Donaldson, 
began a colony of white rats at the University of Chicago. Donaldson eventually established the 
Wistar Institute of Anatomy and Physiology in Philadelphia that became famous for their Wistar 
strain white rats. The Wistar Institute would come to supply many of the most active psychology 
Network Analysis of the JCP  23 
 
 
 
laboratories in the United States. Further information on Donaldson?s and the white rat?s 
influence on psychology is provided by Logan (1999; 2001; 2005).  
The individuals who would later impact comparative psychology were just beginning 
their studies in 1894: Robert Mearns Yerkes was an undergraduate at Ursinus; Edward Lee 
Thorndike was an undergraduate at Wesleyan; and John Broadus Watson was a freshman at 
Furman University.  
Edward L. Thorndike moved from Wesleyan to Harvard in 1896 to begin his graduate 
studies. Working with young chicks in the cellar of William James? home,10 Thorndike?s 
Harvard research on the instinctive nature of pecking behavior in chicks was published in 1899 
(Thorndike, 1899a). Thorndike did not stay long at Harvard, leaving in 1897 to complete his PhD 
at Columbia. Dewsbury cited personal and financial reasons as the cause for the move. In 1898, 
at Columbia, Thorndike completed his thesis entitled, Animal Intelligence: An Experimental 
Study of the Associative Processes in Animals, which immediately became a classic study in the 
history of animal learning. The text primarily dealt with learning in dogs, cats, and chickens. 
Thorndike famously used his puzzle boxes that required an animal to interact with a lever or 
other device in order to escape the box and secure food. Thorndike found that the animals solved 
problems in a trial and error fashion, and did not display reason. His thesis was so influential that 
the results were summarized and published in Science (1898) and in the article ?Do Animals 
Reason?? in Popular Science Monthly (1899b). Thorndike also conducted one of the first ever 
studies of learning in fish, demonstrating escape learning in killifish (Fundulus) (Dewsbury, 
1984).  
                                                 
10 Thorndike?s landlord would not permit the chicks in his room and James was unable to secure laboratory 
space. Thus, Thorndike resorted to conducting his studies in the cellar of William James? home.  
Network Analysis of the JCP  24 
 
 
 
Evidently, this six-year period was extremely important in the development of a 
comparative psychological discipline. The future giants of the field were nearing the start of their 
influential careers: Yerkes entered graduate school at Harvard and in 1899 transferred from 
zoology to psychology; and Watson was one year removed from his historic move to the 
University of Chicago. In 1899, Sanford at Clark, and G.H. Mead at Chicago, began offering 
courses in comparative psychology. Moreover, the first two comparative psychology laboratories 
were placed by Warden and Warner (1927) at Clark, under Sanford, and Harvard, under Yerkes.  
1900-1909 
 The twentieth century began much the same way as the nineteenth century ended, with a 
large degree of optimism towards comparative psychology. As C. Judson Herrick proclaimed in 
1907, ?comparative psychology [had] arrived? (Herrick, 1907, p. 76). Further to the optimism 
that surrounded comparative psychology, this was a time when psychology moved towards 
experimental design over naturalistic observations, and when anecdotal evidence was replaced 
by data derived from experiments (Yerkes, 1943; Dewsbury, 1984). It was also a time when 
learning theory started to gain serious traction in comparative psychology. Still, the comparative 
psychologists at the time understood the importance of natural observation and of studying 
different aspects of behavior (Dewsbury, 1984).  
 Some of the first learning studies at the turn of the century belonged to Small (1900; 
1901) and Thorndike (1901). Using Kline?s puzzle boxes, Small placed white rat?s on the outside 
and food in the inside of the box. This was opposite to what Thorndike had done previously, 
placing the animal in the box and the food outside. Small, like Kline, was extremely vigilant 
about keeping animals in the most naturalistic environment as possible. This was due in large 
part to the orientation of Small compared to Thorndike; Small believed animals do things ?only 
Network Analysis of the JCP  25 
 
 
 
in line of its inherent abilities? (Small, 1900, p. 133), and thus, drew inspiration from Morgan, 
whereas Thorndike cited Lubbock and preferred a laboratory method approach (Dewsbury, 
1984). In Small?s study, the rat had to dig into the box to get the food, and the digging behavior 
was considered in line with the natural characteristic of the rat. In Thorndike?s study, having the 
animal trip a lever or latch to attain food might not have been as naturalistic a setting, but gave 
the researcher the desired experimental control. As learning theory became more dominant in the 
coming decades, Thorndike?s approach became the precedent, and only a few remained loyal to 
the more naturalistic approach that Small advocated. In 1899, Thorndike began researching his 
fourth species after receiving three cebus monkeys and housing them in his residence on West 
123rd Street in New York (Joncich, 1968; Bitterman, 1969). Similar to the conclusions derived 
from his thesis, Thorndike found that the monkeys did not show any signs of reasoning or 
imitation behavior. Furthermore, although Thorndike did admit that the monkeys could learn to 
solve problems other mammals could not, he attributed this to a difference of degree, not one of 
kind. This conclusion that learning did not differ substantially across a wide diversity of species 
had serious implications for the future of comparative learning studies, and animal psychology in 
general (see Beach, 1950; Logan, 2001). 
  During the first decade of the twentieth century, three institutions led the way on 
comparative studies on learning: Harvard, Clark, and Chicago. The Harvard animal lab was 
headed by Yerkes, a Harvard pupil who had just graduated with his doctorate in 1902. Yerkes, 
who figures prominently in the next chapter, studied learning in a wide range of species, 
including turtles (1901); green crabs (1902); frogs (1903); crawfish (Yerkes and Huggins, 1903); 
and dancing mice (1907). His master?s student, Lawrence W. Cole (1907) added raccoons to the 
list of species being studied by those affiliated with Harvard (Pettit, 2010). Although much of 
Network Analysis of the JCP  26 
 
 
 
Yerkes? early work was on learning, he was interested in a whole range of behavioral patterns. 
He would become renowned for his work in the field of primatology and his championing of the 
chimpanzee as a model organism.  
 The Clark laboratory was headed by Sanford and, although much of the early work was 
done by Small and Kline, other Clark workers were conducting comparative experiments as well. 
A.J. Kinnaman (1902), for instance, conducted a laboratory experiment on rhesus macaques. The 
monkeys were expected to interact with and manipulate a number of devices. Unlike Thorndike, 
who claimed there was no evidence of reasoning or imitation in his studies with monkeys, 
Kinnaman found that the monkeys did exhibit reason and imitation. According to Dewsbury 
(1984), Kinnaman was arguably the first to study monkeys in a laboratory setting. However, 
credit for the first use of monkeys belongs to Thorndike. Another Clark student, James P. Porter, 
conducted comparative learning studies on spiders (1906a), and on English sparrows, vesper 
sparrows, and cowbirds (1904, 1906b). Porter also studied ?instinctual? behaviors such as 
mating, web building, and feeding in spiders. One of Sanford?s doctoral students, Herbert 
Burnham Davis, studied intelligence in raccoons, along with a variety of instinctive patterns. 
Alongside Cole and Walter S. Hunter, Davis was one of three major figures in the history of 
raccoon research (Pettit, 2010). Cole and Davis both began studying learning in captive raccoons 
in 1905, and although conducted separate experiments, both studies had much in common. Both 
utilized the newly developed puzzle boxes on a novel organism, with the intention of assessing 
the raccoons? ?comparative place on the scale of animal intelligence? (Pettit, 2010, p. 399).  
 Meanwhile, John B. Watson received his doctorate in 1903 at Chicago, and remained 
there as an instructor. The majority of Watson?s work was done primarily on white rats: his well-
received dissertation (Watson, 1903) was a study on the behavioral development of white rats. 
Network Analysis of the JCP  27 
 
 
 
This study initiated Watson?s meteoric rise in psychology. However, there were those who were 
critical of Watson?s method of sacrificing rats for brain studies. Watson?s work began with the 
caring of Donaldson?s colony. He was not, however, limited to rats only. In 1906, he solicited 
the university to purchase for him four monkeys. The monkeys were used for a study of imitation 
(1908). Like Kinnaman, Watson believed that imitation existed, and he expressed the importance 
of further studies on the phenomenon. In the years 1905 and 1906, the careers of Watson and 
Yerkes intersected via a correspondence, before diverging sharply in later years (Watson became 
a radical behaviorist while Yerkes called himself a psychobiologist). The importance of this 
interaction is highlighted by the status of both men as future giants in the field of comparative 
psychology. Furthermore, Watson?s early allegiance with Yerkes was contrasted by the shaky 
relationship between the Harvard and the Clark labs. Indeed, Yerkes believed that although 
comparative psychology was alive and well at Clark, it was ?indiscreet or bad form for a Harvard 
psychologist to try to cultivate friendly professional relationships with Hall and his Clark 
associates? (Yerkes, 1943, p. 75). This was due in part to the long-standing rivalry between 
William James and Hall, as well as differences in the publishing habits of the two institutions: 
Harvard workers tended to publish brief papers focused on learning in animals; Clark workers 
published longer articles that included extensive introductions, life histories, and points on 
methodology (Dewsbury, 1984). And although Watson did not engage in many comparative 
studies, his student, C.S. Yoakum (1909), conducted learning studies on squirrels and compared 
them to other species.  
 By the end of the 1890s, comparative psychology laboratories had been established at 
Harvard and Clark and comparative courses offered at Chicago and Clark. By 1910, comparative 
courses were offered at Cornell, Drake, Harvard, Ohio State, Iowa, Johns Hopkins, Michigan, 
Network Analysis of the JCP  28 
 
 
 
Mount Holyoke, Oklahoma, and Texas. Moreover, comparative psychology laboratories were 
established at Chicago, Cornell, Johns Hopkins, Michigan, and Texas (Warden &Warner, 1927). 
Evidently, comparative psychology was growing rapidly in America during this decade. Watson 
proclaimed that ?comparative psychology has completely justified its existence? (1906, p. 155). 
He was wary, however, that many topics had been breached and not enough refined. Coupled 
with this lack of refinement was the inadequacy of the available facilities. Thus, with the support 
of Baldwin, Watson called for an experimental station devoted to the study of animal behavior 
(Dewsbury, 1984): 
The need to the psychologist of an experimental station for the study of the evolution of 
the mind is as great as is the need to the biologist of an experimental station for the study 
of the evolution of the body and its functions (Watson, 1906, p. 156). 
1911-1950 
At the turn of the century, the discipline of psychology was changing. Psychologists were 
concerned with their scientific status, leading to a divide in regards to methodology, subject 
matter, and goals of the discipline (Burnham, 1968; O'Donnell, 1979, 1985; Samelson, 1977). 
Not only was psychology in the process of emancipating itself from philosophy, but it was also 
assessing its distance from biology, and determining the degree to which its utility was able to 
justify its existence. Under the pressure of these circumstances, Robert Yerkes and John Watson, 
among others, defined and developed an experimental science based on the study of animal 
behavior, culminating in the establishment of the Journal of Animal Behavior in 1911; one of the 
first institutionalizations of the study of animal behavior (Burkhardt, Jr., 1987). However, 
although Yerkes and Watson were both advocates for the experimental study of overt animal 
behavior, they both took similar, but different approaches. In 1913, Watson published his 
Network Analysis of the JCP  29 
 
 
 
?Psychology as the Behaviorist Views It? in the Psychological Bulletin. This important 
publication essentially became the behaviorist manifesto. Watson called for psychologists to 
leave behind the attempt to study subjective, conscious mental states by means of introspection, 
replacing it with the objective experimental study of overt behaviors (Cohen, 1979; Dewsbury, 
1984; Benjamin, 2007).Watson envisioned the development of a complete program that would 
emphasize the study of behavior in nonhuman organisms and eventually extend its principles to 
human behavior.11 Behaviorism or late-Watsonian behaviorism soon thereafter came to resemble 
an extreme reductionist12 approach, eliminating any influence of inherited factors. Even though 
Yerkes similarly sought to distance himself from psychology as the study of mental experience, 
he did not subscribe to the behavioristic framework purported by Watson and others. Instead, 
Yerkes moved towards psychobiology ?as an integrative discipline with physiology? (Dewsbury, 
1991, p. 200), and established a program of comparative psychobiology at Harvard (Yerkes, 
1930). This research orientation allowed Yerkes to study overt animal behavior without being 
shackled to the increasingly popular behaviorism. Yerkes considered himself a psychobiologist 
rather than a psychologist. Indeed, his autobiography was titled ?Robert Mearns Yerkes: 
Psychobiologist? (Yerkes, 1930).  
Yerkes was not the first individual to use the term psychobiology. In fact, Dewsbury 
(1991) has traced the earliest use of the word to Willard S. Small (1901) in his paper that began 
research on maze learning. Knight Dunlap also considered himself a psychobiologist in the same 
way that Yerkes did. However, the term psychobiology has had many diverse meanings 
throughout history. Yerkes and Dunlap distinguished between three different clusters of uses for 
                                                 
11 The fourth chapter will discuss behaviorism in more detail. 
12Reductionism is a philosophical position that holds that a phenomenon is nothing more than the sum of their 
parts, and the object of study could be understood by its individual constituents (Jones, 2000; 2013) 
Network Analysis of the JCP  30 
 
 
 
psychobiology: the first one was the way it was used by E.S. Russell; the second cluster was 
Adolf Meyer?s use of the term; and the third their own meaning of the term.  
Edward Stewart Russell was a prominent British biologist whose Form and Function 
(1916) sought to change classic morphology into a functional morphology. For Russell, the 
organism ? that he perceived as purposive ? had to be studied holistically, including both the 
morphological with behavior. He termed this approach ?hormic biology? (Russell, 1923; 1924). 
His use of psychobiology came in his opposition to vitalism. Russell argued that it was 
purposiveness that distinguished between living and non-living things and that purpose was 
studied through a psychobiological (functional) method in biology. 
 The Swiss-born psychiatrist, Adolf Meyer was a long time professor of psychiatry and 
director of the Phipps Clinic at Johns Hopkins University. He used psychobiology to define his 
holistic approach to psychiatry as the integration of social, psychological, and biological factors 
to better treat patients (Meyer, 1915). Psychobiology was a way for Meyer to deal with ?the 
functions of the whole person and not merely as detachable parts? (Meyer, 1915, p. 861). 
Dewsbury (1991) also noted that most definitions of psychobiology define it in the way Meyer 
used it. This is not surprising considering the influence Meyer had on Dunlap, Watson, and many 
others in this era (Dewsbury, 1991; Billings, 1939).  
  In 1914, Knight Dunlap published a textbook entitled, An Outline of Psychobiology. The 
book most closely resembled what would today be called physiological psychology (Dewsbury, 
1991). Dunlap believed that ?[he] raised this term from its grave, and employed it as covering the 
consideration of biological materials and theories from the point of view of the bearings of these 
on the problems of psychobiology? (cited in Dewsbury, 1991, p. 199). Dunlap also founded and 
served as executive editor of Psychobiology, a periodical that published two volumes in 1917 
Network Analysis of the JCP  31 
 
 
 
and 1920. Psychobiology, for Dunlap, was the interconnection between mental and physiological 
functions, and could also be called ?physiological psychology.? Moreover, Dunlap?s 
psychobiology also encompassed investigations in pharmacology, physiology, neurology, 
anatomy, and psychiatry as long as these investigations had bearing for problems in mental life 
(Dunlap, 1917). Although Yerkes accepted Dunlap?s use of psychobiology, his research interests 
were much broader and his work was less physiological and more behavioral. Yerkes also 
applied the term to distance himself from mainstream psychology, in particular, behaviorism.  
 It appeared that Yerkes and Dunlap at least believed they were using the term similarly 
(Yerkes, 1934). However, there appears to be little continuity in the way they used the term 
compared to Meyer?s use. Dunlap, in particular, believed that Meyer used the term in a 
philosophical manner, which he claimed bore no resemblance to his usage of the term. Meyer 
echoed these differences in how he used psychobiology compared to Dunlap and Yerkes. He 
believed Dunlap?s use was too narrow and academic, and indicated the difference between him 
and Yerkes was the latter?s acceptance of mental causality (Dewsbury, 1991). For the purposes 
of this study, I used Dunlap and Yerkes?s integrated definition of psychobiology. That is to say, 
?psychobiology? as an integration between psychology and physiology, and as a way to 
distinguish behavioral research from behaviorism. 
Before beginning the analysis of Dewsbury?s claims on the status of comparative 
psychology in the twentieth century, it is important to unpack some of his arguments. He was not 
convinced by the type of frequency counts employed by Schneirla, Beach, and other writers who 
revisited the ?Snark.? For Dewsbury, the percentage of comparative research studies on the lab 
rat did not matter nearly as much as the quality of comparative research and its impact on the 
wider discipline. He believed that focusing on quantity and percentages alone actually served to 
Network Analysis of the JCP  32 
 
 
 
distort the image on the history of comparative psychology. His main thesis in the book however, 
was that although comparative psychologists were a small part of the wider psychological 
discipline, their achievements were noteworthy. Indeed, he argued that these same comparative 
psychologists developed and maintained the comparative discipline, and provided reason to be 
proud of the history of the discipline rather than apologetic. He asserted that a community of 
comparative psychobiologists maintained ?a consistent thread? of excellence throughout the 
history of the comparative discipline.  
 Although Dewsbury acknowledged the achievements of many prominent comparative 
psychologists, he focused mostly on a handful of prominent psychobiologists that were highly 
impactful in maintaining comparative psychology. According to Dewsbury, during the 1910s, 
three individuals were key contributors to the development and establishment of comparative 
psychology, Yerkes, Watson, and the newly arrived Karl Spencer Lashley. However, although 
early a proponent of the study of animal behavior and comparative psychology, and highly 
influential in the development of the comparative field, Watson moved away from comparative 
psychology in the mid 1910s towards human based research.  
Dewsbury recognized the early 1920s as a transition period for comparative psychology. 
Lashley had just taken up a position at the University of Minnesota where one of his students and 
future significant comparative psychobiologist, Calvin Perry Stone, graduated. But mostly, the 
early 1920s was a time ripe with controversy over instincts and behaviorism, with many (neo) 
variations on behaviorism being offered. However, Dewsbury claimed that the return of Yerkes 
to academia in 1924, coupled with the influence of Lashley and the graduation of Stone, H.C. 
Bingham, and Carl J. Warden provided the boost necessary for comparative psychology to 
prosper in the late 1920s and early 1930s.  
Network Analysis of the JCP  33 
 
 
 
It was Dewsbury?s characterization of the 1930s that was most distinct from other 
historians. Historians like Misiak and Sexton (1966) described the 1930s as a time of decline in 
comparative psychology. Moreover, Beach claimed that the 1930s saw the greatest rise in the 
percentage of research articles on the rat. However, Dewsbury argued that the graduation of a 
?new generation? of prominent comparative psychobiologists made this decade one of the most 
notable in the history of comparative psychology. Including Yerkes, Lashley, and Stone, 
Dewsbury acknowledged the importance of the arrival of Norman Raymond Frederick Maier, 
Harry Friedrich Harlow, Winthrop Niles Kellogg, and Frank Ambrose Beach in the 1930s. These 
comparative psychobiologists were also largely responsible for Dewsbury?s characterization of 
the 1940s as a decade of sustained vigor. 
 Dewsbury?s argument is predicated on the achievements of these prominent comparative 
psychobiologists. It is for this reason, then, that I have chosen to track these individuals 
throughout the period of 1911 to 1950 in the JCP. Although Dewsbury has accurately depicted 
the qualitative prominence of these individuals? achievements, I argue that these comparative 
psychobiologists were also quantitatively prominent. I measured their quantitative prominence 
by assessing how many organisms they published on in the JCP, and the total number of 
publications they contributed to this journal, both at the individual and institutional level. Thus, I 
conclude that Dewsbury was correct in his assessment of comparative psychology as a small, yet 
vigorous discipline. I decided to focus on two generations of comparative psychobiologists over 
two chapters. The first generation, covered in chapter one, included Yerkes, Lashley, and Knight 
Dunlap. The second generation, covered in chapter two, was made up of Stone, Maier, Harlow, 
Kellogg, and Beach. Dewsbury did not consider Dunlap a comparative psychologist because he 
studied mostly humans. However, I argue that his close connection to the JCP as executive 
Network Analysis of the JCP  34 
 
 
 
editor, his self-identification as a psychobiologist (Dewsbury, 1991), and his research on four 
different organisms not only qualified him as a comparative psychobiologist, but made Dunlap 
one of the most influential individuals in comparative psychology?s history. My argument will be 
constructed as follows: I begin with a biographical sketch of the three ?first? generation 
comparative psychobiologists and then assess their individual and institutional influence on 
comparative psychology via the information derived from the networks. The higher their 
influence in the network, the more confident I am in arguing for Dewsbury?s characterization of 
comparative psychology as a small, important discipline maintained by a handful of prominent 
psychobiologists.  
Network Visualizations 
In this section, I introduce visual networks that depict the metadata collected from the 
Journal of Comparative Psychology (JCP) from its inception in 1911 to the year 1950. The 
metadata collected from the JCP was obtained strictly from substantive articles (reviews, notes, 
and theoretical papers were excluded) and included: year, organism studied, first author,13 and 
institutional affiliation. The data was then organized in a spreadsheet and imported in the 
software Gephi. Two different forms of networks were created, one depicting the relationship 
between organism and author, and the other depicting the relationship between organism and the 
institution. For this project, I constructed my argument based on three aspects of the network.  
The first aspect was assessing the authors and institutions connected to the most diverse 
array of organisms. This is measured using degree. A high degree is indicative of many distinct 
connections, and a low degree is indicative of very few distinct connections. In this project, a 
high degree represents the use of a comparative research approach or the use of a wide diversity 
                                                 
13 Including any co-authors distorts the quantitative measures in the network. If a co-author was prominent 
enough, they would eventually appear as a first author. 
Network Analysis of the JCP  35 
 
 
 
of organisms. The second aspect was the total number of connections (not necessarily distinct) 
between an author/institution and the organisms they studied. This is measured using weighted 
degree, which takes into account all instances of a relationship between an author/institution and 
the organisms. The higher the weighted degree, the more articles were published by an author or 
institution. Thus, a high weighted degree indicates the most prolific authors/institutions in terms 
of output. The third and final aspect was the determination of a particular author?s position in the 
network. This is often referred to as the spatial layout of the network. I expect that the most 
comparative authors, connected to the most organisms, would be positioned nearest to the center 
of the network. In contrast, the authors connected to only one organism would be positioned 
more peripherally in the network. I argue that authors positioned near the center of the network 
were more integral to the overall structure of the network, and most likely to have been 
mediators or conduits between different organism clusters.  
Reading the networks from the vantage point of these three aspects allowed me to infer 
certain things about the comparative psychobiologists under study. For instance, a high degree 
indicated a researcher had studied multiple organisms in a particular time frame, and thus, had 
been comparative in their research program. In the context of my argument, studying multiple 
organisms was an important marker of a comparative psychobiologist. Weighted degree 
indicated which researchers were the most prolific or productive contributors (quantity) to this 
journal in a specified time frame. These productive researchers, at least quantitatively, were 
some of the most active in the field, and thus, were influential in the maintenance of the 
comparative discipline. Degree and weighted degree are not only useful measures for assessing 
the specified researchers at the individual level, but they also contribute to the structural 
positioning of a particular researcher in the overall network. Degree dictates how far a researcher 
Network Analysis of the JCP  36 
 
 
 
will be positioned from the center of the network and how many different communities they 
connect, and weighted degree influences the force or strength a particular researcher has over 
nearby nodes. For example, if a researcher node has a higher weighted degree than an organism 
node, the researcher node will have a stronger gravitational pull. In this study, I expected the 
specified comparative psychobiologists to have been highly comparative (high degree) as well as 
having been prolific contributors to the journal (high weighted degree). With these high 
centrality measures, I also expected them to be positioned as mediators, connected to multiple 
communities near the center of the network, with stronger than average gravitational pull. 
The First Generation: Robert Mearns Yerkes, Knight Dunlap, and Karl Spencer Lashley 
 Robert Yerkes was arguably the most important individual in the establishment and 
maintenance of comparative psychology. Not only did he establish the Journal of Animal 
Behavior, but his efforts helped develop an experimental program of comparative psychobiology 
in an era dominated by behavioristic theories. Yerkes was first educated at Ursinus College, 
receiving his A.B. degree in 1897. In the same year, he moved to Harvard where he took his A.B. 
degree in 1898, and his A.M. degree in 1899. Interest in zoology and psychology led Yerkes to 
comparative psychology and, at the suggestion of Josiah Royce, Yerkes transferred over to the 
psychology department to work in animal psychology. He received his PhD in 1902 under Hugo 
M?nsterberg (Yerkes, 1930) and subsequently founded the Harvard laboratory of comparative 
psychology (Dewsbury, 1984). Yerkes remained at Harvard in various roles -- assistant, 
instructor, and professor -- for the next fifteen years. As the Great War broke out, Yerkes 
accepted a position at the University of Minnesota as chair of the psychology department, which 
was newly separated from the philosophy department, but he never physically went there. Yerkes 
was integral in mobilizing psychologists during World War I, and remained as an administrator 
Network Analysis of the JCP  37 
 
 
 
after the war had ended. In 1924, he moved to Yale as Professor of Psychobiology, where he 
remained until his retirement in 1942.  
 Like Yerkes, Knight Dunlap was also a self-proclaimed psychobiologist who was 
extremely influential to comparative psychology and the JCP (Dewsbury, 1991). His education 
began at the University of California where he received his BPhil in 1899. From there, he moved 
to Harvard where he took his PhD in 1903. He encountered many of the same mentors and 
influences as Yerkes did (M?nsterberg, Royce, Dewey, and James) since both were at Harvard 
during the same period. In 1904, he took a faculty position at Berkeley before moving to Johns 
Hopkins University in 1906. He remained there for three decades, leaving in 1936 to establish a 
psychology laboratory and graduate program at the University of California, Los Angeles 
(Dorcus, 1950; Moore, 1949; Dewsbury, 1984). Dunlap was also vehemently against the current 
definitions of instincts;14 the only one of the three psychobiologists with this disposition. 
Coupled with his doctrine that good research resulted from assuming the opposite stance, Dunlap 
was an unpopular iconoclast (Dorcus, 1950).  
 The third comparative psychobiologist, Karl Spencer Lashley, was different from the 
other two in that he never self-identified as a psychobiologist. Rather, the label was applied to 
him by the historian, Donald Dewsbury (2002). Dewsbury?s justification was, first, that his 
initial training was a PhD in zoology that he obtained under Herbert Spencer Jennings at Johns 
Hopkins University in 1914. Thus, much of Lashley?s work was biologically oriented. And 
second, through a series of learning experiments in the 1920s, Lashley dismantled the stimulus 
response theories of the day. Clearly, he was interested in behavior but not sympathetic to the 
behaviorist approach. He was, however, influenced by Watson during his graduate training, 
                                                 
14 The concept of ?instincts? have been an important and controversial debate throughout the entire history of 
the psychological discipline (see Dewsbury, 1984 for a detailed account). 
Network Analysis of the JCP 38 
conducting field studies with Watson on terns on the Dry Tortugas in 1913. After attaining his 
doctorate, he worked with Shepherd Ivory Franz before joining the Minnesota faculty in 1917. 
He remained there until he went to the Institute for Juvenile Research (affiliated with the 
University of Illinois in Chicago) in 1926. His next stop was the University of Chicago in 1929. 
He left for Harvard in 1935, remaining there for the remainder of his career until 1955. While at 
Harvard, from 1942 to 1955, he held the position of director of the Yerkes Laboratories of 
Primate Biology.
Psychobiologists in the Network 
The first network I looked at included the entire period of 1911 to 1950 (Figure 1). The 
network was weighted by using the number of organisms studied (degree). In other words, 
emphasis was placed on the number of organisms one studied rather than the number of studies 
published. Before determining how these three psychobiologists were depicted in the network, it 
is important to describe what one is seeing. This network consists of 760 nodes (authors and 
organisms) and 894 edges. Often, an author might have been studying multiple organisms, 
indicating why there are more edges than nodes in this network. Of the 760 nodes, 57 were 
organisms and 703 were authors. From a ?bird?s eye? perspective, the network appeared as a 
collection of clusters of various sizes. The largest cluster was made up of 348 distinct authors 
studying the rat for a total of 747 published articles on the organism (degree=348, weighted 
degree=747). The next largest cluster consisted of 127 distinct authors studying the human and 
publishing a total of 185 articles (d=127, wd=185). This trend of the rat and human being the two 
most studied organisms was seen throughout all versions of the networks. Table 1 presents the 
fifteen largest organism clusters in terms of degree and weighted degree, and Table 2 shows the 
top fifteen most comparative and productive researchers.
39
Network Analysis of the JCP 40 
The three comparative psychobiologists, Yerkes, Lashley, and Dunlap, boasted not only a 
comparative approach, but were some of the most highly productive researchers in the JCP from 
1911 to 1950. In terms of studying multiple organisms, Yerkes had the most comparative 
approach of any other author in the JCP, studying eight different organisms: rat, human, 
chimpanzee, monkey, dove, worm, pig, and bird. Lashley studied five different organisms: rat, 
bird, cat, monkey, and chicken. And Dunlap studied four different organisms: rat, human, bird, 
and rabbit. All three psychobiologists studied both birds and rats, Yerkes and Lashley examined 
monkeys, and Dunlap and Yerkes ran experiments on humans. (Yerkes? experiments on humans 
came during his time in the war effort).  
Despite the commonalities in species choice, each of the three had their own preferred 
organism: Yerkes favored the chimpanzee; Lashley preferred the rat for his neurological and 
perception research; and Dunlap felt that studying the psychological conditions of humans were 
most fruitful. Some might argue that Dunlap?s preference of the human made him a non-
comparative psychobiologist (see Dewsbury, 1984), but I argue that his studies on the rat, bird, 
and rabbit displayed his comparative breadth. Yerkes and Lashley both began by studying a 
number of different organisms before ?finding? and sticking with their respective favored model. 
Dunlap took a different approach, beginning his studies on the human, moving to the rat, rabbit, 
and bird, before eventually returning to the human. Yerkes believed that anthropoids were the 
closest organism to humans, and thus, chose the chimpanzee as the ideal subject to investigate 
sexual and social behavior for the ?welfare of mankind? (cited in Biehn, 2008, p. 21). Lashley?s 
research revolved around neurological bases of learning, anatomical structures of the brain, 
sensation and perception, and the effects of drugs on learning (Hebb, 1959). The small, 
abundant, and inexpensive rat was the most amenable and logical organism for this type of 
Network Analysis of the JCP 41 
research. Dunlap?s interest in the field of vestibular research ? which he picked up from a brief 
stint in the army ? led to his and his students? choice of human subjects (Dorcus, 1950).  
In terms of the quantity of research published in the JCP, these three psychobiologists 
also were among the top. From 1911-1950 Karl Lashley published 14 articles, Robert Yerkes 
contributed 12 papers, and Knight Dunlap authored 11. The majority of each researcher?s 
repertoire, however, was focused on their preferred standard organism, establishing a close 
connection between the two. Along with degree, this close connection contributed to their 
positioning as close to the node representing their desired organism. For instance, Yerkes? strong 
connection to the chimpanzee positioned the two very nodes close to one another in the network. 
Moreover, since Yerkes employed a highly comparative approach, their representative nodes 
were located closer to the center of the network than the periphery. Similarly, Lashley?s close 
connection with the rat kept him close to that species than any of the other four he studied. His 
connection to five different organisms also kept him close to the center of the network. Finally, 
Dunlap?s affinity to the human brought him close to that species cluster, and his degree of four 
kept him nearer the center. As I mentioned earlier, I argue that the closer a node (in this case a 
researcher) is to the center of the network, the more influential to the overall structure of the 
network and of the discipline itself. When the network is weighted on degree, in order to be near 
the center, a node must have multiple connections throughout the network. Thus, scientists near 
the center of the network are connected to multiple organism clusters, acting as conduits that 
presumably mediate the flow of information between communities of researchers and organisms. 
If we look at the degree and weighted degrees of these psychobiologists, and by consequence, 
their position in the network, we can argue that not only were these researchers some of the most 
comparative and productive in the discipline, but they were also mediating information between 
Network Analysis of the JCP 42 
different ?communities? of researchers and organisms. In this respect, Yerkes, Lashley, and 
Dunlap were integral in maintaining the comparative discipline. However, such a large time 
period (1911-1950) does not allow us to make any claims on smaller time intervals. 
The Early Years (1911-1930) 
The period from 1911 to 1950 provided a general view of the discipline over several 
generations. However, it was difficult to discern any information about the early years when 
viewing the data over such a long time frame. For this reason, I split the time period of 1911-
1950 in half, focusing on the early years from 1911 to 1930, and the later years from 1931-1950. 
The network covering the period of 1911 to 1930 (Figure 2) consisted of 313 nodes and 335 
edges. This new, smaller network, comprised of two dominant clusters, the human (d=71, 
wd=100) and the rat (d=70, wd=119), a number of smaller clusters (cat, monkey, chicken, dog), 
and a few dyadic and triadic clusters (see Table 3 for full degrees and weighted degrees of fifteen 
largest organism clusters). Similar to Figure 1, this network was weighted by degree, and thus, a 
researcher studying diverse organisms would once again be positioned nearer to the center of the 
network.  
In Figure 2, Yerkes, Lashley, and Dunlap were circled to make them easier to spot. The 
majority of Yerkes?s work came within the years of 1911 to 1930 (only three articles were 
published by Yerkes in the JCP after 1930). Even in this smaller network, Yerkes (d=8, wd=9) 
had the highest degree of any author, and thus, he was positioned near the center of the network. 
His high occurrence with the chimpanzee kept him closest to that organism, rather than the other 
organisms he studied, like the human or the rat. The opposite occurred as well: whereas the 
chimpanzee, monkey, pig, bird, dove, and worm influenced where Yerkes was positioned, he 
also influenced where these organisms were positioned in the network. 
43
Network Analysis of the JCP 44 
Indeed, Yerkes had a higher degree and weighted degree than the chimpanzee, worm, pig, bird, 
and dove. In simpler terms, Yerkes, an author, was connected to more species than the number of 
distinct researchers that were studying either one of the previously mentioned organisms. A node 
with a higher degree has a higher gravitational force in the network, drawing closer nodes with 
smaller degrees. Similar to Yerkes, the majority of Lashley?s publication output came in the 
period of 1911 to 1930. With a degree of five and weighted degree of 12, Lashley published 
twelve articles in this period, with only two articles on the rat published in the JCP after 1930. 
The comparative Lashley was also located near the center of the network, however, his nine 
articles on the rat kept him closer to that organism. Lashley was also connected to the relatively 
large cat, monkey, and chicken clusters. Dunlap, in opposition to the other two, was equally 
active before and after 1930, in the JCP. From 1911 to 1930, Dunlap studied three organisms for 
a total of six articles. Of the three authors, he was the only one who did not study the rat in this 
network. Instead, he conducted four studies on the human, and one each on the bird and rabbit. 
His studies on three organisms placed him in the center of the network, but closer to the human 
cluster. In this period, all three psychobiologists were positioned in the network to have 
presumably been mediating the flow of information between multiple organism communities. 
The Later Years (1931-1950) 
Figure 3 depicts the next time period, from 1931 to 1950. This network consisted of 526 
nodes and 591 edges. The rat cluster exponentially eclipsed the human cluster in this time frame. 
The rat (d=293, wd=628) was studied nearly eight times more than the next closest organism, the 
human (d=61, wd=85). (Table 4 depicted the degrees and weighted degrees of the top fifteen 
organism clusters). The rise of the rat could be indicative of the spread of neo-behavioristic 
theory in the 1930s ? even though the rise of the rat as a subject species was a discipline wide
45
Network Analysis of the JCP 46 
phenomenon (see Logan, 2002, 2005) ? or could simply be an artifact of more data in this 
network than the other. The increase in the number of articles published in this period caused 
each cluster to grow as well, but none reached the rat?s growth rate: in the period after 1930, four 
times as many researchers studied the rat, and five times as many articles were published on the 
rat (all figures taken from the JCP) compared to the next closest organism.  
Since the majority of Yerkes?s and Lashley?s work was done prior to 1931, it was no 
surprise to find that they each had a degree of one and a combined weighted degree of 5 (Yerkes 
published three articles and Lashley published two). Indeed, Yerkes retired as director of the 
Yale Laboratories of Primate Biology (YLPB) in 1942, and began writing his magnum opus, 
Chimpanzees: A Laboratory Colony (Biehn, 2008).15 He also resumed his position in the war 
effort during World War II (Dewsbury, 1984). Lashley succeeded Yerkes as the new director of 
the Yale Laboratories of Primate Biology in 1942 and conducted much important primate work 
himself (Carmichael, 1959). However, none of this work on primates was published in the JCP. 
In fact, Lashley stopped publishing in the journal after he moved to Harvard in 1935. Even 
though Lashley and Yerkes did not publish in the JCP in these later years, their respective 
?standard? organisms, the rat and chimpanzee, continued to be studied more often. Knight 
Dunlap was fairly active, studying the human and the rat during this time period, and producing a 
total of five articles. Although he was not one of the more prolific contributors in this network, 
Dunlap?s connection to the rat and human positioned him as one of the few authors who 
mediated the two largest clusters in the network.  
Viewing the network in three different time periods, I was able to determine the extent 
and timing of these psychobiologists? influence in comparative psychology. Robert Yerkes, the 
founder of the Journal of Animal Behavior and the initial driving force of a comparative 
15 For a full account of Yerkes?s retirement, see Biehn, 2008. 
Network Analysis of the JCP 47 
psychobiology, studied the most diverse array of organisms of any other researcher. In terms of 
production, Yerkes conducted twelve studies, which was modest amongst the leaders. By 
breaking the time period in half, it became apparent that the vast majority of Yerkes? work came 
prior to 1930, explaining his modestly high output. Karl Lashley exhibited a similar trend to 
Yerkes insofar as most of his research output came in the period before 1930. Lashley 
contributed a total of fourteen articles on five organisms. Dunlap was less comparative and 
prolific overall than Yerkes and Lashley, publishing eleven articles on four organisms. However, 
unlike Yerkes and Lashley, Dunlap was equally as active before and after 1930. With this 
information in hand, it appeared Dewsbury was astute in characterizing Yerkes, Lashley, and to a 
lesser extent, Dunlap, as the driving force for the development and establishment of a 
comparative discipline in the 1910s and its maintenance in the transitional period of the 1920s. 
Indeed, after the 1930s, Dewsbury placed the success of comparative psychology in the hands of 
the newly graduated generation of psychobiologists. 
Up till now, we have only looked at one type of network depicting the relationship 
between researcher and organism. Thus, we have been able to determine the influence of these 
comparative psychobiologists on an individual basis. In order to determine their influence at the 
institutional level in developing and maintaining the discipline, a different type of network 
needed to be used depicting the association between organisms and institutions. The next section 
tracked trends in organism choice at the institutions these psychobiologists were affiliated with. 
In particular, I sought to determine how much of an institution?s experimental approach to the 
study of animals (comparative or a single model organism) was attributed to the psychobiologist 
they employed and whether or not the prominence of that institution was associated with the 
prominence of their resident psychobiologist. I argue that if the institutions that employed 
Network Analysis of the JCP 48 
Yerkes, Lashley, and Dunlap were prominently contributing to the JCP in a similar manner to 
their in-house comparative psychobiologist (prominence measured by quantity of publications 
and the diversity of organisms studied), then the psychobiologists along with their institutions 
were influential in sustaining the comparative discipline. 
Institutional Affiliation of the Psychobiologists 
There was a large amount of overlap between the institutions at which these three 
psychobiologists researched and taught, and thus, their careers were interconnected. For instance, 
at the same time Yerkes took his doctorate at Harvard, Dunlap began his graduate training at the 
same institution. The connections did not stop there, however. Dunlap held a position as 
professor of psychology at Johns Hopkins when Lashley arrived as a student. When Lashley 
graduated from Hopkins, in 1917, he was hired by Yerkes as an instructor at Minnesota. 
Although Yerkes did not physically go to Minnesota, he still made hiring decisions. Indeed, 1917 
was a busy year for Yerkes, who assumed the presidency of the APA, and chair of the 
Committee on the Psychological Examination of Recruits where he oversaw the administration 
of the Army Alpha and Beta tests (Yerkes, 1930; Benjamin, 2007). Yerkes moved to Yale in 
1924 where he would spend the rest of his career; the latter portion of which was spent as 
director of the YLPB. Lashley went from Minnesota to the Institute for Juvenile Research in 
1926, before taking a position at the University of Chicago in 1929. Later, Lashley went to 
Harvard in 1935 ? making all three psychobiologists affiliated with Harvard at some point in 
their careers ? and stayed until his retirement in 1955 (Hebb, 1959). He also succeeded Yerkes as 
the director of the YLPB. Dunlap was at Johns Hopkins until 1936 when he moved to UCLA to 
establish a graduate program in psychology (Zusne, 1975). 
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Network Analysis of the JCP 50 
In Figure 4, the relationship between institution and organism is depicted for the period 
of 1911 to 1950. The network consists of 278 nodes (225 were institutions and 53 were 
organisms) and 512 edges. Table 5 shows the top six institutions by degree and weighted degree. 
Since I was interested in the institutions that these psychobiologists were stationed at, and 
because the time in which they were there varied in the period from 1911 to 1950, I was unable 
to determine any association between the researcher and his institutional influence in this large 
network. Thus, I viewed the data in the arbitrarily chosen time frames used earlier: 1911 to 1930, 
and 1931 to 1950. This allowed me to examine Harvard when Yerkes was there, John Hopkins 
under Dunlap, and so on. 
Institutions in the Early Years (1911-1930) 
Figure 5 depicts the institution-organism network from 1911 to 1930. This network 
consisted of 178 nodes and 247 edges. During this period, Yerkes was at Harvard and Yale, 
Dunlap was at Johns Hopkins, and Lashley was at Johns Hopkins and Minnesota. Thus, for this 
time period, I was only interested in tracking the trends in these four institutions. Yerkes, 
studying the most diverse array of organisms in the JCP, established the comparative psychology 
laboratory at Harvard and, thus, it is fitting that Harvard researchers boasted the most 
comparative laboratory of any institution. To be sure, Yerkes was executive editor of the JCP 
(then titled Journal of Animal Behavior) from 1911 to 1916, and determined how his home 
institution was to be represented while he was there. Of the institution?s 22 different subject 
species, 20 of them were studied in this period. Furthermore, the Harvard laboratory had not yet 
decided on a ?standard? with which to work: only nine of 29 articles were published on an 
already studied organism. Indeed, Yerkes had not found the chimpanzee until his return to 
academia in 1924, when he had long since left Harvard. Rosalia Abreu, prior to the war, had 
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51
Network Analysis of the JCP 52 
contacted Yerkes about visiting her vast collection of primates in Havana. Abreu had 
successfully managed the conception and birth of a chimpanzee, the first person to do so in the 
Western Hemisphere. Her collection included marmosets, monkeys, baboons, mandrills, apes, 
gibbons, orangutans, and chimpanzees. He began his investigations on apes in the summer of 
1924 (Dewsbury, 1984).  
Yale University was not particularly productive in this period. Of the 70 articles 
published by Yale?s comparative psychology researchers, only 16 appeared in this period across 
six different species. Much of this inactivity was due to the dismantling of the Yale psychology 
department at the turn of the century. Edward W. Scripture, a former doctoral student of Wilhelm 
Wundt?s, founded the Yale psychological laboratory in 1892 (Benjamin, 2007; Garvey, 1929); 
although some credit the founding to George Trumbull Ladd16 (Burnham, 1971). With the arrival 
of a new President, Arthur Twining Hadley, and the subsequent philosophical differences, 
Scripture was forced to resign, Ladd was dismissed, and the psychology department folded until 
James Rowland Angell succeeded Hadley as President of Yale (Kuklick, 2004; Burnham, 1971). 
Angell brought in Yerkes in 1924, and immediately Yerkes began his psychobiological work 
with chimpanzees under the Yale patronage (specifically: Yale Laboratories of Comparative 
Psychobiology). Yerkes and Angell revived the Yale psychology department until Clark L. Hull 
arrived in 1929 and turned it into a hub for neo-behavioristic research (Benjamin, 2007; Sears, 
1982; Rumbaugh, 1997). 
During this entire period, Knight Dunlap was stationed at Johns Hopkins. Hopkins 
researchers, with a degree of 14, were the third most comparative laboratory (behind Harvard 
16Ladd was a psychologist in his writings and philosopher by title, but during a time when most psychological 
programs were still part of philosophy departments, this was not an uncommon occurrence. He was brought to Yale 
in 1881 to teach philosophy and psychology and soon thereafter headed up Yale?s department of Mental Philosophy 
(Burnham, 1971).   
Network Analysis of the JCP 53 
and Chicago). However, Hopkins was the most productive laboratory at the time, publishing 
nearly double the number of articles as their closest competitor: Johns Hopkins researchers 
published 62 studies compared to the 32 by Chicago researchers. Twenty-nine of these studies 
were on the human, the ?standard? organism in Dunlap?s psychobiological research. Much of 
Dewsbury?s research was focused on child, industrial, and abnormal psychology. The rat was 
also commonly studied in this period, albeit by only a few researchers: of the 15 rat studies, four 
were by Lashley and five by the graduate student J.L. Ulrich. Moreover, rabbits, which Dunlap 
studied in 1925, featured in four articles.17 It appeared that Dunlap had greatly influenced the 
?standard? organism of his laboratory, but also influenced the output of his department. By 1921, 
Yerkes and Dunlap co-founded the Journal of Comparative Psychology, and although both men 
were executive editors, Dunlap took on the majority of the editorial duties (Burkhardt, Jr., 1987; 
Moore, 1949). I would argue that Dunlap exerted his influence as executive editor and favored 
the research coming from his own institution in addition to studies on humans. The American 
Journal of Psychology has been similarly criticized as G. Stanley Hall favored the research of 
friends and students, both former and present (O?Donnell, 1985). I believe the JCP served a 
similar purpose for Dunlap, although further research is needed. 
Lashley contributed eight of his 14 articles while at Johns Hopkins. Four of these articles 
were on the rat, and the other four indicated the extent of his comparative approach (monkey, 
chicken, cat, bird). Lashley was at Minnesota in various capacities from 1917 to 1926. Yerkes 
hired Lashley in 1917 as instructor before resigning his post to take up his position on the 
National Research Council. Yerkes replaced himself with his Harvard assistant and colleague in 
the Army Testing Project, Richard M. Elliot (Department History, 2013; Hebb, 1959). Upon his 
arrival, Lashley was surprised to find no Yerkes and a deficient working environment. Although 
17 This might have been due to the convenience of already having a rabbit in captivity. 
Network Analysis of the JCP 54 
Lashley taught at Minnesota in 1917, he did not publish under its affiliation until Elliot had 
appointed him assistant professor in 1920, relieving him of his teaching duties. Lashley was 
never particularly good at teaching, and it was a research position he was after (Hebb, 1959). 
Like Yale, Minnesota was not particularly productive in this period with only 15 articles on two 
species (rat, human). However, the Minnesota Philosophy and Psychology department did not 
split into two separate departments until 1917 (Department History, 2013), and thus, the 
psychology laboratory was just a fledging enterprise. Still, Lashley?s influence early on was 
strong. Quite literally, Lashley or his students were the only individuals publishing on any 
species under the Minnesota affiliation in the JCP from 1920 to 1929. This included Carney 
Landis? important dissertation on human emotional behavior that appeared across four papers 
(1924; 1925; 1926; 1926), Calvin P. Stone?s (1922) dissertation on the copulatory activity in the 
male rat, and the articles of two of his female students, Ruth M. Hubbard (1927) and Mary 
Shirley (1928; 1928; 1928), who published their dissertations on discrimination in learning and 
neural activity of the rat.18 Lashley published three articles on the rat while at Minnesota. He left 
in 1926 to the Institute for Juvenile Research where he published one article on the rat. The next 
section focused on the years from 1931 to 1950. 
Institutions in the Later Years (1931-1950) 
Figure 6 depicts the time period of 1931 to 1950 and consisted of 189 and 322 edges. In 
this time frame, Yerkes had his Orange Park facility in Florida,19 and began distancing himself 
from the other Yale researchers. He now published under the patronage of the Yale Laboratories 
18 A third female student, Dorothea McCarthy, co-authored on Lashley?s 1926 paper dealing with cerebral 
injuries in rats. Since she was second author, however, she was not present in the author-organism dyad. Shirley and 
Hubbard took their PhDs studying experimental psychology with Lashley. McCarthy, along with another female 
student, Esther McGinnis, took their PhDs from the Institute of Child Development run by Anderson and 
Goodenough (About the Institute, 2013). 
19 Yerkes considered this a three-point operation that included a facility in New Haven and fieldwork overseas. 
On June 10, 1930, a day after the facility was built, four chimps moved in from Yale. 
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Network Analysis of the JCP 56 
of Primate Biology until he retired in 1942. Dunlap was at Johns Hopkins until moving to UCLA 
in 1936 to take up a position as Professor and Chairman of the Department of Psychology, 
remaining there until retiring in 1946 (Moore, 1959). Lashley held multiple positions in this 
period: he was at Chicago from 1929 to 1935, Harvard from 1935 to 1955, and at the YLPB from 
1942 to 1955. Thus, this section focused on the YLPB, Chicago, Johns Hopkins, Harvard, and 
UCLA. 
Researchers at the YLPB began to publish under this affiliation in the JCP in 1934. From 
1934 to 1941, while the YLPB was under the control of Yerkes, 35 articles were published. From 
1942 to 1950, under Lashley?s leadership, only 14 articles were published. Also in 1942, the 
YLPB became a joint venture between Yale and Harvard (Dewsbury, 1984); no doubt due to 
Lashley?s incumbency at Harvard. In total, 49 articles came from the YLPB in this journal, 40 of 
which were on the chimpanzee. The YLPB was not only the most prolific primate laboratory of 
the era in terms of articles, but by 1941, the Yale Laboratories of Primate Biology (later the 
Yerkes Laboratory of Primate Biology in 1942) would boast the largest collection of 
chimpanzees anywhere at forty-five (Gray, 1955; Hahn, 1971). The other nine articles were 
written across six different species (humans, rats, minnows, octopus, guinea pigs, and pigeons).  
While at Johns Hopkins in this time period, Dunlap only studied the rat. Upon his move 
to UCLA, he returned to studying the human once again. During this time in the JCP, it was rare 
for a researcher to distinguish between the Berkeley and Los Angeles campuses of the University 
of California: the majority of researchers characterized their affiliation as being with the 
?University of California.? To avoid misattributing a researcher to the wrong campus, I decided 
to record all instances as the University of California. Thus, it is impossible to determine 
Dunlap?s influence in the overall publishing trends of the institute. However, considering the 
Network Analysis of the JCP 57 
goal of his move was to establish a psychology laboratory and graduate program, I would 
presume that Dunlap was tied up with more administrative tasks. It is interesting to note the 
sudden drop off in productivity from Johns Hopkins. In this time period, Hopkins researchers 
published 33 articles on six species; the seventh most productive laboratory in terms of number 
of articles. Compared to the 62 published in the previous time period, the Hopkins laboratory 
productivity dropped by half in a time when the total number of articles being published in the 
JCP was increasing. This might have been due to Dunlap?s departure in 1936 (who remained 
editor until 1943), or by the growing influence of the more behavioristically inclined institutions 
(this will be discussed in more detail in the fourth chapter).  
Although Lashley only published two articles on the rat while at Chicago, he appeared to 
have left his mark. Throughout the period of 1911 to 1950, Chicago had always been near the top 
in both degree and weighted degree. This was mostly due to the organizational skill of Harvey 
Carr. Under his guidance, Chicago served as one of the most prolific psychology departments of 
any university, which took a functionalist and comparative approach in their research (Carr, 
1927; Pillsbury, 1955). However, Lashley?s research in the 1930s revolved around pattern 
perception and his mixture of behavioral and anatomical methods subsequently resulted in the 
increase of papers dealing with the rat?s brain mechanisms coming out of the Chicago laboratory. 
His lasting contribution to the institution, however, came from his influence on future Chicago 
research, and his specific impact on two individuals, David Krech and Yu-Chuan Tsang. Upon 
receiving his doctorate from Berkeley in 1933, Krech went to Chicago with a National Research 
Council Fellowship to work alongside Lashley, and stayed until 1937. In the years Krech was at 
Chicago, he served as Lashley?s assistant and published six articles on the rat; the most any 
Network Analysis of the JCP 58 
researcher had at Chicago from 1911 to 1950 in the JCP.20 Yu-Chuan Tsang was much less 
prolific than Krech, publishing only three papers on the rat; two in 1937, and one in 1938. 
However, in each of his articles, in a footnote, Tsang acknowledged that he ?is indebted to 
Professor K. S. Lashley for suggestions and encouragement? (Tsang, 1938, p. 1). Lashley?s 
influence remained for years after he had left in 1935.  
Most interestingly, however, was the pattern Harvard research took in this period. After 
Yerkes had left Harvard, in 1917, the department began to fade in terms of its productivity in the 
JCP. Indeed, only five of the institutions 29 articles came between 1918 and 1930. Furthermore, 
the institution did not publish a single article from 1931 to 1936. With the arrival of Lashley to 
Harvard in 1935, the psychology department was revived. Lashley, himself, did not publish an 
article while affiliated with Harvard. However, two patterns suggest that the Harvard laboratory 
was influenced considerably by Lashley. First, an institution that had long been established as 
comparative became suddenly invested in a single organism: the rat. Harvard?s degree of three in 
this period was a far cry from its degree of 20 in the previous period. Moreover, of the 
institutions 26 articles, 23 were on the rat, the organism that Lashley had long determined as his 
?standard.? Second, Harvard researchers began publishing in the JCP again in 1937, the year 
Lashley obtained his coveted role of research professor in neuropsychology. Furthermore, these 
researchers publishing in 1937 were former students of Lashley?s, Frank Beach and Donald O. 
Hebb, who followed Lashley to Harvard (Dewsbury, 2002).  
This chapter sought to test Dewsbury?s claim that comparative psychology did not just 
fade into behaviorism, but maintained a consistent thread of excellence throughout its history. In 
particular, this chapter focused on the first generation21 of comparative psychologists, Robert 
20 Krech published under his birth name, Ivan Krechevksy. 
21 By no means is this a suggestion that comparative work did not begin until these three arrived. 
Network Analysis of the JCP 59 
Yerkes, Karl Lashley, and Knight Dunlap, that Dewsbury credits with institutionalizing 
comparative psychology and sustaining it through a period of transition (in the 1920s). To 
determine this, I analyzed the data collected from the JCP that was displayed in a network 
visualization, looking specifically at the degree, weighted degree, and positioning of Yerkes, 
Lashley, and Dunlap. I determined that all three of these comparative psychologists were among 
the most comparative and prolific contributors to the JCP, and were each positioned as conduits 
near the center of the network, connecting and mediating the flow of information between 
multiple communities of researchers and organisms. I also analyzed these three individuals at the 
level of their institutional affiliation. Here, I found that the institutions employing their 
respective psychobiologist adopted their distinct approach and standard laboratory organism. 
Moreover, these institutions were amongst the most active contributors to the JCP. Another 
finding came from the overlap and intertwining of these institutions. The leading 
psychobiologists were affiliated with a small handful of institutions in which they moved around 
and replaced each other. That Lashley replaced Yerkes at Minnesota and Orange Park was not 
accidental, but instead part of a larger initiative to continue the psychobiological tradition. 
Thus, Dewsbury?s assertion that a thread of excellence was maintained in comparative 
psychology due to a handful of individuals was quantified through the networks. A further 
influence of Yerkes and Dunlap that cannot be explicitly seen in the network (can only be 
inferred) were their positions as editors of the journal: Yerkes from 1911 to 1916, and Dunlap 
from 1917 to 1943. The next chapter assesses the second part of Dewsbury?s claim that 
comparative psychology prospered in the 1930s and 1940s off the achievements of a newly 
graduated crop of comparative psychologists. 
Network Analysis of the JCP 60 
Chapter Two: New Generation of Comparative Psychobiology 
The argument in this chapter that comparative psychology prospered on the backs of a 
?new generation? of comparative psychobiologists rests on the premise that the comparative 
psychobiologists discussed here were indeed psychobiologists. Although some of the new crop 
of comparative psychologists were characterized by Dewsbury (2002) as psychobiologists 
(Beach and Maier), the majority have rarely been titled as such. Thus, to show that these 
individuals could be constituted as psychobiologists, I used Yerkes? and Dunlap?s integrative 
definition as the determining criteria: that the researcher employed some intersection between 
psychology and biology in their study of behavior, and that they did not subscribe to the 
prevailing behavioristic framework of the day. 
Some of the individuals that made up Dewsbury?s (1984) ?new generation? of 
comparative psychobiologists were, in chronological order, Calvin P. Stone, Norman R. F. 
Maier, Harry F. Harlow, Winthrop N. Kellogg, and Frank A. Beach. My criteria for inclusion 
were as follows: the scientists had to have been identified by Dewsbury as important 
comparative researchers; and each scientist must have contributed at least ten first-author 
publications to the JCP from 1911-1950. Similar to the previous chapter, my argument will be 
constructed as follows: it begins with a brief biographical sketch of these researchers, illustrating 
how these individuals were indeed psychobiologists. Next I assess their influence at the 
individual and institutional level in the JCP using the measures of degree, weighted degree, and 
overall positioning in the network. The more active a researcher in the JCP, the more influence 
that individual was likely to have been in contributing to the growth of the comparative 
discipline. This belief was integral to the interpretation of the data.  
Biographical Sketch of the ?New Generation? 
Network Analysis of the JCP 61 
Calvin Perry Stone entered the comparative sphere the earliest amongst the five ?new? 
comparative psychobiologists. After receiving his BS in 1910 and BA in 1913 in different 
departments at Valparaiso University, and a brief stint as a high school teacher, Stone moved to 
Indiana where he received his MA under Melvin E. Haggerty in 1916. Stone followed Haggerty 
to Minnesota, but his graduate career was interrupted by The Great War. After the war, he 
returned to Minnesota where he was primarily influenced by Lashley, taking his PhD under 
Lashley?s supervision in 1921 (Rosvold, 1955; Dewsbury, 1984; Hilgard, 1994). Stone?s 
dissertation was titled, ?An experimental analysis of the congenital sexual behavior of the male 
Albino rat.? By this time, Lashley was a seasoned rat researcher, so it is no surprise that Stone 
moved towards rat research. In fact, Lashley suggested the problem to Stone that materialized 
into his dissertation on the copulatory behavior of male rats (Hebb, 1959).  
The next comparative psychobiologist to earn his doctorate was Norman Raymond 
Frederick Maier. Maier began his studies in Michigan where he received his BA at the 
University of Michigan in 1923. After, he travelled abroad for a year of graduate work in 1925 
and 1926 to the University of Berlin where he studied under Wolfgang K?hler, Max Wertheimer, 
and Kurt Lewin. Upon his return to Michigan, he completed his doctorate under the supervision 
of John F. Shepard, before moving to join the faculty at Long Island University in 1928 and 
1929. From there, he became a National Research Council Fellow at the University of Chicago 
between the years 1929-1931, where he was afforded the opportunity to work with Karl Lashley 
and Heinrich Kl?ver. At Chicago, Maier began his research studying reasoning in humans 
(Maier, 1930) and guinea pigs (although not in the JCP), before moving to problem solving in 
rats. In 1931, Maier returned to Michigan, where he held a faculty position for the majority of his 
career (Dewsbury, 1984; Solem & McKeachie, 1979). 
Network Analysis of the JCP 62 
Winthrop Niles Kellogg was next to enter the discipline. He first attended Cornell 
University in 1916 and 1917, but like many of his compatriots, he left to serve in the war. At the 
war?s end, he enrolled in Indiana University where he obtained his degree in philosophy and 
psychology in 1922. Kellogg subsequently went to Columbia, receiving his MA in 1927, and 
doctorate in 1929 under the supervision of Robert S. Woodworth. His dissertation, which 
compared psychophysics methods, characterized his early research (Deese, 1973). Kellogg 
joined the Indiana faculty in 1929, and first began publishing in the JCP in 1931; a study on fear 
behavior in rats, birds, and mice. He spent the majority of the 1931-32 academic year at the 
Orange Park facility, where using a research leave funded by the Social Science Research 
Council, he conducted his most (in)famous study, The Ape and the Child (1933). In this 
controversial developmental study, Winthrop raised his son, Donald, alongside a chimpanzee 
named Gua. Gua was obtained from the YLPB on June 26, 1931 when Donald was nearly one 
year old, the experiment lasting until March 28, 1932 (Dewsbury, 1984; Benjamin & Bruce, 
1982). He returned to Indiana in 1933, and published learning studies on humans (1935) and 
water snakes (1936) in the JCP, before choosing the dog as a subject. This coincided with 
Kellogg?s establishment of a special dog conditioning laboratory in 1936 (Kellogg, 1938; 
Benjamin & Bruce, 1982). The remainder of Kellogg?s work at Indiana revolved around 
conditioning and learning in dogs.  
 Harry Friedrich Harlow22 was directly connected to both Lashley and Stone. Stone, who 
took his doctorate under Lashley, supervised Harlow during his PhD. Harlow spent his entire 
graduate education at Stanford, obtained his BA in 1927, and PhD in 1930. Although Stone was 
Harlow?s supervisor, Harlow was also influenced by Lewis M. Terman and Walter R. Miles who 
22 Harry Harlow was born Harry Israel but was encouraged by Terman to change his name to improve his job 
prospects. Although he was not of Jewish descent, his last name would cause people to assume he was (Rumbaugh, 
1997). 
Network Analysis of the JCP 63 
were both at Stanford at the time (Sears, 1982; Rumbaugh, 1997; Dewsbury, 1984). Like his 
supervisor had done to him, Stone attempted to direct Harlow toward rat research early on, 
assigning him a ?pedestrian rat problem [that] soured [Harlow] forever on both rats and 
parametric research? (Sears, 1982, p. 1280).23 Harlow was brought in to the University of 
Wisconsin in 1930 to take up a position as comparative psychologist and director of the animal 
laboratory. Upon his arrival, Harlow discovered there was no such laboratory (Sears, 1982; 
Rumbaugh, 1997), and instead, began studying primates, including the monkey, at the Madison 
Zoo. There are two different accounts describing this event (Rumbaugh, 1997). The first recounts 
that Harlow, an accomplished bridge player, was given the suggestion of studying primates at the 
Madison Zoo by his department chair?s wife during an evening of cards (Rumbaugh, 1997). The 
second account credited the suggestion to Clara Mears, a teaching assistant in educational 
psychology, and Harlow?s future wife in 1932 (Sears, 1982; Rumbaugh, 1997). In any case, to 
avoid working with rats, Harlow began research on primates at the Madison Zoo; he began with 
apes, baboons, lemurs and orangutans, before choosing the monkey (Sears, 1982; Rumbaugh, 
1997). 
The last of the new generation of comparative psychobiologists discussed here was Frank 
Ambrose Beach. Beach took his undergraduate training in English in 1932, and then took his 
Master?s in clinical psychology at the Kansas State Teachers College. His MA thesis was on 
color vision in rats, and was developed from his own ideas. He moved to Chicago for a year of 
graduate school on the promise of a $400 stipend from functionalist Harvey Carr. At Chicago, he 
came under the influence of Carr, L.L. Thurstone, and Lashley. With his fellowship at Chicago 
complete, he taught at a high school in Kansas, before returning back to Chicago in 1935 to 
23 Harlow did not start publishing in the JCP until 1932, and thus, none of his work at Stanford appeared in the 
journal. 
Network Analysis of the JCP 64 
finish his studies. By that time, Lashley had left for Harvard and Beach would eventually follow 
him there after the completion of his doctoral dissertation in 1936. Although Beach completed 
his doctoral dissertation on the cortical control of maternal behavior in rats while at Chicago in 
1936, he did not actually take his doctorate until 1940 when he was stationed at the American 
Museum of Natural History. Beach spent the academic year of 1936/37 working in Lashley?s 
laboratory at Harvard and, in 1938, he took a position at the American Museum of Natural 
History (AMNH) in the Department of Experimental Biology. Beach remained there until 1946 
before leaving to Yale, and eventually Berkeley (Dewsbury, 1989; Dewsbury, 1984). His time at 
the AMNH exposed him to the comparative study of organisms other than the rat, which perhaps 
led to his critique of psychology?s overuse of the rat (Pettit et al., forthcoming/2015). 
In the previous chapter, we saw several commonalities between Yerkes, Lashley, and 
Dunlap. The most important of which were the similarities in laboratory organisms studied and 
the comparative approach each employed. The five psychobiologists in this chapter also shared 
many of the same laboratory organisms: Stone, Maier, Kellogg, and Harlow studied the human 
subject; Stone, Maier, Kellogg, and Beach experimented on the rat; and Stone and Kellogg both 
conducted research on the dog and the house mouse. However, three distinct experimental 
approaches emerged from these five researchers. Stone, Kellogg, and Harlow took a more 
comparative approach, studying multiple organisms early in their careers before settling on a 
model organism. Maier took a more narrow approach in terms of the diversity of his study 
species. And Beach began his career focused solely on one species before employing a more 
comparative approach later on in his career (beyond the time period of this thesis). Indeed, the 
comparative tag attributed to Maier and Beach by Dewsbury (1984) referred more to their 
influence on the comparative discipline and less to the diversity of organism used in their own 
Network Analysis of the JCP 65 
research. Nonetheless, the two were still amongst the most active contributors to the JCP and 
influential in sustaining the discipline. In fact, Maier was the most active of all researchers, 
conducting 25 studies from 1930 to 1950. See Table 2 for the fifteen most comparative and 
productive authors. 
All five of these psychobiologists were highly active in the JCP from 1930 to 1950, 
publishing at least ten articles each. However, only Stone was publishing prior to 1930. Stone, 
Kellogg, and Harlow featured as the most comparative researchers (studying the most diverse 
organisms) behind only Yerkes. Harlow was the second most comparative studying seven 
organisms (human, cat, monkey, ape, lemur, orangutan, and baboon), while Stone (human, rat, 
dog, mouse, horse, rabbit) and Kellogg (human, dog, rat, mouse, bird, and snake) tied for the 
third most comparative at six. Maier (rat and human) and Beach (rat) studied two and one 
organism, respectively. Like their predecessors, all five psychobiologists had their preferred 
model organism. Stone, a student of Lashley, predictably favored the rat, publishing fifteen 
articles with it as subject. Maier, who also worked under Lashley, chose the rat for his studies on 
reasoning ? which Maier believed was distinct from learning ? publishing 22 of his 25 articles on 
the rat. Kellogg, who conducted much work on conditioning (Benjamin & Bruce, 1982), 
published six of his ten articles on the dog. Harlow preferred the rhesus macaque amid his 
primate subjects, conducting nine of his twelve studies on the animal. And finally, Beach, 
inspired by Carr and Lashley, experimented on the rat in all eleven of his studies. Moreover, 
each of these five ?found? their standard organisms in different ways. Stone (1921) conducted 
his MA thesis on light discriminations in dogs, but quickly moved to the rat. He studied the other 
organisms intermittently throughout his career. Maier began his career alternating between the 
human and the rat before settling solely on the rodent. Harlow and Kellogg took a similar pattern 
Network Analysis of the JCP 66 
in finding their model organism: both started with a comparative approach before choosing the 
monkey and dog, respectively. Beach, a product of Carr and Lashley at Chicago, chose the rat 
from the start. Ironically, Beach, who favored the rat, was perhaps best known for his critique 
that the discipline had become over-reliant on the animal, criticizing his own research in the 
process. Later on in his career, Beach employed a more comparative approach. 
Determining a Psychobiologist 
As mentioned above, the argument in this thesis is contingent on the characterization of 
these five individuals as psychobiologists. Otherwise, it would be impossible to distinguish 
between a rat researcher operating under a behavioristic framework and one operating outside 
the behavioristic paradigm. Moreover, it is important that this characterization be spelled out 
prior to the network analysis. To determine whether or not these individuals were 
psychobiologists, I employed Yerkes? and Dunlap?s definition of the term which states that 1) 
behavior must be studied at the biological and psychological level and 2) the research problems 
be approached from non-behaviorist theoretical viewpoint. To be characterized as a 
psychobiologist, the researcher must have adhered to both aspects of the definition. This 
appeared to be the case. The first individual I assessed was Calvin P. Stone. 
Stone was the most blatant advocate for the biological aspects of behavior of the five. For 
Stone, understanding behavior included studying its genetic basis, development, and control at 
the endocrine level. Such a strong predisposition to the biology of the organism was expected 
considering Stone?s background in physiology and anatomy. For certain, having Lashley as a 
supervisor,24 whom many considered a physiological psychologist (Hebb, 1959), ensured Stone?s 
24 In the past, many considered Lashley only a ?physiologist.? Although he trained primarily in biology and  his 
work entailed neurology and neurophysiology, Lashley considered himself a psychologist foremost and was most 
interested in the study of behavior (Hebb, 1959).  Some historians now recognize him as a psychobiologist 
(Dewsbury, 2002). 
Network Analysis of the JCP 67 
training in the physiological mechanisms of behavior. Additionally, while at Minnesota, he was 
also influenced by the anatomy professor, A.T. Rasmussen (Rosvold, 1955; Hilgard, 1994; 
Dewsbury, 1984). Stone?s early work highlighted instinctive behavior and the relationship 
between physiological mechanisms and reproductive behavior; work he was considered the 
pioneer of (Dewsbury, 1984). Later in his career, Stone moved more towards the study of maze 
learning, and drew attention to the importance of studying abnormal behavior. Stone, like 
Lashley, could have always been considered a physiological psychologist, but with his later work 
on the effects of electroconvulsive shock on learning, he moved closer to the physiological side. 
Perhaps it is coincidental, but he also took on executive editorship of the JCP when its name was 
changed to include ?Physiological Psychology.?  
Although Stone ventured into studies on learning behavior, he was far from a behaviorist 
and never wavered from his physiological psychological research program. In fact, Stone is 
remembered for his uncompromising stance that psychologists needed to stick to the ?well-
grounded fundamentals,? and his ability to remain undeterred by the pedagogical trends 
associated with behavioristic theory (Rosvold, 1955, p. 328; Dewsbury, 1984) Further separating 
him from the behaviorisms of Hull and Skinner was his visible promotion of the study of 
instincts, culminating in the ?Symposium on Heredity and Environment? held on April 10, 1947 
in conjunction with the meetings of the Society of Experimental Psychologists at Princeton. 
Stone joined the likes of Beach, Leonard Carmichael, Lashley, and Clifford T. Morgan as 
speakers, while Walter S. Hunter served as discussant. All the papers, published in the 
Psychological Review, argued for the existence of instincts. Stone?s participation in this 
symposium, coupled with his APA presidential address in 1942 entitled, ?Multiply, Vary, Let the 
Strongest Live and the Weakest Die ? Charles Darwin,? and his studying of maternal behavior 
Network Analysis of the JCP 68 
and other instinctual behavioral processes, led to the characterization of Stone as a 
psychobiologist and his research program as comparative psychobiological. 
Norman Maier had already been characterized by Dewsbury (2002) as a psychobiologist, 
and his research program supported this assertion. Like Stone, he was also highly influenced by 
Karl Lashley, their careers intersecting during Maier?s fellowship at Chicago from 1929-1931. 
Lashley?s influence surfaced in Maier?s use of the Lashley Jumping Stand and his study of 
behavior at the neural level. Using the Lashley Jumping Stand, a device that required rats to 
jump from a small platform to the target area, Maier (1939) claimed to have discovered two 
forms of neurotic behavior in rats. After the rats learned a simple discrimination, they were 
presented with an unsolvable problem and displayed two different behaviors: some became 
fixated with a particular choice that when presented with a solvable problem, they continued to 
make that same choice; and others experienced full-fledged seizures that sometimes lasted 
several minutes. Maier believed both behaviors were similar to the types of neuroses prevalent in 
humans, but later conceded that only the fixations were indicative of neurotic behavior (Maier, 
1939; Dewsbury, 2010; Dewsbury, 1993). Maier, who was already considered a Maverick in 
psychological circles, drew the ire of the behaviorists with this research, especially with the 
public support it was given being awarded the $1000 Newcomb Cleveland Prize; the first 
psychologist to be given this award by the American Association for the Advancement of 
Science (for a full account, see Dewsbury, 2010). His research ran counter to the dominant 
behavioristic trends of the day and, for this reason, it was attacked by mainstream psychologists. 
Although Maier successfully defended his theories, his research was not accepted and he was 
later forced out of academia. He became a successful industrial psychologist (Dewsbury, 1993). 
Network Analysis of the JCP 69 
Kellogg?s approach to his research might be described as ?Natural Curiosity.? Of the 
five, Kellogg was the most likely to have been a behaviorist, considering his work on 
conditioning and learning in multiple organisms. However, Kellogg never adopted such a 
framework. In fact, it was this atheoretical position, along with his personality, that put him in 
such a precarious situation at Indiana. Kellogg spurned theory, arguing that it blinded researchers 
from seeing important findings or misinterpreting results. For him, science belonged to natural 
curiosity. At a time when researchers adhered to one learning theory or another, Kellogg?s 
position was unpopular; not only at Indiana, but at many institutions in the 1930s and ?40s. 
Moreover, with behaviorism looming large in learning studies, Kellogg?s curiosity was akin to 
Titchener?s science for science?s sake; perhaps something he learned while at Cornell in 1916. 
Kellogg, opposed to behavioristic theory, was also actively involved in researching the biological 
aspects of his organisms. His famous study with Gua the chimpanzee focused on the 
development of the primate, and his later work on echo localization in the dolphin?s sonar system 
was inherently biologically based. Thus, like Stone and Maier, Kellogg was characterized as a 
psychobiologist. 
Harlow, a product of Stone and Stanford, also benefitted from a strong background in 
physiology and neuroanatomy. As such, his early interests were in the cortical localization of 
higher intellectual functioning (Sears, 1982). It was this focus on ?higher? intelligence that 
contributed to his choice of monkeys as subjects since they evidently showed high cognitive 
capacity. This early focus on the biological aspects interested him, but not nearly as much as his 
serendipitous finding of ?learning sets,?25 the process by which an organism learns to learn 
(Sears, 1982, p. 1280; Dewsbury, 1984; Rumbaugh, 1997). In the process of constructing his 
Wisconsin General Test Apparatus standard battery ? the standardized set of measures he needed 
25 Wolfgang K?hler and Robert Yerkes similarly found that their primates learned to learn (Rumbaugh, 1997). 
Network Analysis of the JCP 70 
to examine higher intelligence at the central nervous system level ? he witnessed his monkeys 
displaying one-trial learning on simple discrimination problems. First, they responded through 
trial-and-error fashion, much the way conventional learning theory indicated, but eventually, the 
monkeys ?caught? on to a shortcut in the process, using insight to display one-trial learning. This 
finding sent shockwaves throughout the discipline, forcing behaviorists to develop more 
cognitive theories. Indeed, Sears (1982) considered it his ?first victory in his battle with the Yale 
[Hull] brand of behavior theory? (p. 1280). Interestingly enough, Harlow only discovered the 
monkey?s ability to learn to learn because the depression of the 1930s meant he only had access 
to a few monkeys and had to use the same ones in successive trials. 
A second finding of Harlow?s threatened to dismantle the idea of primary drive reduction 
as a reinforcer that was at the center of Hull?s behaviorism. In a study in which monkeys were 
well-fed, Harlow found that curiosity was a stronger motivator than hunger, a finding that was 
earlier purported by Lawrence Cole, an MA student of Yerkes, with his work on raccoons (Pettit, 
2010). Harlow set up a chamber in which monkeys were given an opportunity to work a gadget 
in order to open up a peephole to see a toy electric train on a track. He found that the monkeys 
worked for hours on difficult discrimination problems to witness this real life toy in action. Yet, 
Harlow was perhaps best known for his work on the development of affectional systems in 
monkeys. This research ?included the development of ?surrogate mothers? and studies of mother-
infant relationships, sibling relationships, abnormal behavior, and therapy? (Dewsbury, 1984, p. 
302). This brought Harlow back to his biological roots, but also came from his on-going effort at 
dismantling primary-drive theory. Again, this finding was serendipitous and came from his 
attempt to start his own breeding colony of rhesus macaques. Harlow separated the infants from 
their mothers for fear of spreading any pervasive diseases that the mothers brought with them 
Network Analysis of the JCP 71 
from India. He found that the infants thrived physically, but were deprived emotionally and 
refused to mate as adults. This led to his ?surrogates,? the wire and cloth mothers (Sears, 1982). 
Harlow?s commitment to the biological processes, and his obvious disbelief in 
behaviorism, not only made him a psychobiologist, but led Rumbaugh (1997) to characterize his 
theoretical approach as ?rational behaviorism? because his theory was ?one that was to tumble 
the Jerichonian walls of Thorndike's bondage?[and] the habit strength of Hull and his drive-
reduction framework? (p. 202, 204). 
Similar to Maier, Dewsbury (2002) had already characterized Frank Beach as a 
psychobiologist. And like Stone and Maier before him, Lashley?s mentorship was pervasive in 
Beach?s career, influencing his organism choice and his research program. Beach first studied 
under Lashley when he was brought to Chicago by Harvey Carr, and like many of Lashley?s 
students, he eventually followed his mentor to Harvard in the late 1930s. Carr and Lashley put 
Beach onto the rat as a research subject early on in his career. However, Beach?s rat research was 
of the psychobiological variety, dealing with reproductive behavior at the endocrine and neural 
level (Dewsbury, 1984; Dewsbury, 1989; Pettit, 2012). Further purporting the importance of 
biology in his research program, Beach is credited as a major contributor to the establishment of 
behavioral endocrinology as an important field of inquiry. 
Beach?s opposition to behaviorism was highlighted by his paper entitled, ?The Snark was 
a Boojum? in 1950. He did not so much oppose the behavioristic framework for its inherent 
defects, like Harlow did, but rather opposed its displacement of comparative psychology. Beach 
feared that behaviorism had turned comparative psychology into the study of maze learning in 
rats, and argued that if change was not enacted, the comparative discipline would soon disappear. 
Thus, based on Yerkes? and Dunlap?s definition of psychobiology, it is safe to characterize these 
Network Analysis of the JCP 72 
five researchers as psychobiologists. The establishment of this characterization was an integral 
part of the overall argument, and provided the necessary foundation to make any claim about the 
influence of these researchers within network and by extension, the overall discipline. The next 
section investigates the influence of these individual comparative psychologists in the network. 
The New Generation in the Network 
It is clear from the biographical sketches that all five of these authors were highly active 
contributors to the flagship journal of the discipline. And with the exception of Beach and Maier, 
these psychobiologists were some of the most comparative researchers around. Thus, strictly in 
terms of quantity, it would appear that these five researchers were highly influential in helping 
comparative psychology ?prosper? in the 1930s, and maintain its ?vigor? in the 1940s. This next 
section sought to assess their influence in the structure of the network through their positioning. 
As was seen in the previous chapter, a researcher?s position in the network is highly influenced 
by their degree and weighted degree. The higher one?s degree, the more connected the researcher 
will be, and will likely position them closer to the center of the network. The closer one is to the 
center indicated that that researcher was likely to have been mediating the flow of information 
between multiple organism communities. Moreover, a high instance between a researcher and 
organism (multiple studies on the same animal) determines the spatial closeness of those two 
representative nodes in the network.  
Figure 7 depicts the same time period from 1911 to 1950 with these five psychobiologists 
circled. Stone (d=6, wd=21), Maier (d=2, wd=25), and Beach (d=1, wd=11) were all predictably 
closest to the rat. Stone, being the most comparative of the three, was positioned closest to the 
center (on the right side of the rat). Beach, who only conducted studies on the rat, was furthest 
from the center (left side of the rat), and positioned more on the periphery. However, Beach?s  
73
Network Analysis of the JCP 74 
eleven studies on the rat made him one of the spatially closest researchers to the rodent. Maier, 
who also studied the human, was positioned at the bottom of the rat node, and like Dunlap, acted 
as a conduit between the two largest communities of researchers. Harlow (d=7, wd=15), to no 
surprise, was closest to the monkey. Kellogg (d=6, wd=11), however, was noticeably positioned 
closer to the mouse? in which he conducted only one study ? than the dog. This appeared to be 
caused by his connection to the bird, located at the bottom of the network. In contrast to Stone, 
who was positioned closer to the center, Harlow and Kellogg were positioned closer to the edge 
of the network. This was no doubt due to their minimal engagement with the rat and human 
subjects. The fact that the rat was located at one end of the network, and the monkey and dog at 
the other end, reflects that very few researchers who studied rats were also studying the other 
two organisms. Indeed, Beach (1950) argued that most researchers studying the rat were not 
studying other organisms at all. Again, I looked at the network diachronically, splitting the time 
period from 1911 to 1930 and from 1931 to 1950.  
The Early Years (1911-1930) 
Since this chapter focuses on the new generation of comparative psychobiologists, it is 
unsurprising that only two of the five psychobiologists were publishing in this time period. 
Figure 8 displayed the network from 1911 to 1930 with Stone and Maier circled. Stone published 
eight articles in this period, six on the rat, and one each on the dog and rabbit. Maier only 
published one article on the human, and thus, was positioned on the far left side of the network. 
Stone?s first publication on light discrimination in dogs came in 1921, and thus, his eight articles 
came over a span of ten years. Since the majority of his work was on the rat, he was closest to its 
cluster. Notice how Stone appeared on the left side of the rat cluster rather than the right. The 
researchers on the rat side were those only studying the rat. However, since Stone was also  
75
Network Analysis of the JCP 76 
studying the dog and rabbit, he was positioned on the left side and acted as a liaison to the dog 
and rabbit nodes. He was also located in the main part of the network (in between the rat and 
human clusters), asserting his influence in the network?s structure. 
The Later Years (1931-1950) 
The second network, from 1931 to 1950, with all five authors circled, was depicted in 
Figure 9. Stone, who was prominent in the earlier network, was even more productive and 
influential in this time period: he conducted thirteen studies, nine on the rat, two on the human, 
and one each on mice and horses. Whereas in the last period Stone?s close connection to the rat 
brought him closer to the center, in this period, his close connection to the rat pulled him further 
from the center. The network, in this period, was partitioning into two parts, the rat researchers, 
and a collection of other clusters of various sizes. However, Stone, like Dunlap, was one of the 
few individuals connecting the rat and human cluster, so he did not fall too far from the center. 
Stone was also one of three researchers studying both rats and mice ? the others being R. 
Heimburger and I.A. Mirsky. Stone?s structural prominence in the network was also attested to 
by his connection to the horse. The horse was being studied by two individuals in this period: 
Stone and L.P. Gardner. Gardner, who also studied cows and sheep, was not connected to the 
main network. Thus, Stone was the sole reason for the direct connection of the horse to the main 
network.  
Norman Maier conducted 24 studies in this time frame: two on the human and 22 on the 
rat. Maier was the most productive of any of the researchers, and his many studies on the rat 
made him one of the closest to the cluster. However, his two studies on the human kept him 
firmly positioned on the right side of the rat cluster, and once again, positioned him as one of the 
77
Network Analysis of the JCP 78 
handful of researchers that mediated the two largest communities of researchers. Maier?s 
influence was mostly seen in how productive he was in this period. 
Harlow?s comparative work on multiple primates, coupled with no connection to the rat, 
led to his location on the far right side of the network, and separation from the main of the 
network. In terms of statistics, Harlow was the most comparative psychologist in this period, 
studying seven organisms; closely followed by his student, Abraham Maslow (who studied at the 
Madison Zoo with Harlow), and Kellogg, who each studied six species. Harlow was also tied as 
the second most eminent psychologist with a weighted degree of 15 ? behind only Norman 
Maier?s staggering 24. Marion Bunch also had a weighted degree of fifteen. Harlow?s location 
near the edge of the network seemed to dismantle the argument that a high degree positions a 
researcher near the center; however, this was not the case. With no connection to the rat ? the 
main part of the network ? and the fact that he was studying nearly all the primates that appeared 
in this journal, he created and centered his own primate community within the network. 
Moreover, the majority of monkey researchers were studying only the monkey and were, 
accordingly, positioned on the right side of the organism. Harlow, who was studying humans, 
lemurs, orangutans, apes, baboons, cats and monkeys, was located on the left side of the monkey, 
or what can be termed the ?comparative side.? Harlow?s nine publications on the monkey also 
made him the foremost monkey researcher in the network. Yet, he was closest to the baboon and 
ape. This was easily explained: since the baboon and ape had low degrees, three and two 
respectively, they were more likely to be influenced by the much more prominent Harlow 
(degree of 7), and thus, be drawn closer to his representative node. Further purporting Harlow?s 
importance in the network, he was the only researcher in the entire network that conducted 
studies on orangutans and lemurs, and was the reason the two primates appeared in the network. 
Network Analysis of the JCP 79 
He was also one of two individuals, the other being B. Weinstein, who connected both the 
monkey and human clusters, and the only primate researcher connected to the cat cluster. 
All of Kellogg?s work came in this period. His ten articles on six species were broken 
down as follows: six on dogs, and one each on the rat, human, mouse, bird, and snake. Kellogg?s 
location in the lower middle part of the network was due in most part to his high occurrence with 
the dog; the dog cluster was located at the very bottom of the network. Indeed, alongside W.T. 
James, Kellogg conducted the most studies on dogs of any other researcher. Similar to Dunlap, 
Stone, and Maier, Kellogg was also a mediator between the rat and human cluster. However, 
with only one article on each organism, he was not similarly positioned in between the two 
clusters. The closest species to Kellogg was the bird. As was seen in the case with Harlow, the 
bird, with a smaller degree of five, was drawn closer to the larger degree of Kellogg?s (6). The 
Indiana psychologist was also connected to the mouse and the snake. Kellogg?s prominence in 
the network was also seen in the idiosyncratic connections he made: he was the only researcher 
studying dogs and mice; and one of only three researchers connecting the rat and dog clusters 
(the other two being E.L. Walker, C.B. Woodbury).  
Of all the psychobiologists, Frank Beach probably exerted the least influence on the 
overall structure of the network. However, his eleven studies of the rat did make him one of the 
foremost rat researchers of the day. There is a caveat when assessing Beach?s influence in 
comparative psychology during this period. Beach was the youngest of all the psychobiologists 
discussed in this thesis, and thus, did not start publishing in the JCP until 1937. Moreover, most 
of his comparative research did not begin until after 1950 when he had left the American 
Museum of Natural History. During his time at the Museum, he became interested in European 
Network Analysis of the JCP 80 
ethology and served as a conduit between it and American comparative psychology after the 
Second World War.  
Dewsbury?s argument appeared to have been supported not only by the quantitative 
measures of the new generation of psychobiologists, but also by their positioning in the network. 
Even though Maier and Beach were not as comparative as Stone, Kellogg, and Harlow, their 
productivity made them two of the most eminent rat researchers in the entire discipline that 
adhered to a psychobiological framework instead of the dominant behavioristic paradigm. Stone, 
Kellogg, and Harlow represented the new generation of truly comparative psychobiologists that 
maintained the tradition of studying a diversity of organisms in an era when the rat was the 
preferred model organism in many scientific disciplines. These three were also amongst the most 
active contributors to the journal. Thus, these five individuals did indeed help comparative 
psychology prosper in the 1930s, and prosper the discipline did: from 1911 to 1929, 366 articles 
were published in the JCP compared to the 1040 published from 1930 to 1950; an increase of 
nearly threefold. The next section investigated the influence of these individuals from the 
institutional level. 
Institutional Affiliation of the New Generation 
There were several commonalities among these five authors. Both Stone and Kellogg 
began their graduate careers at Indiana. After taking his MA, Stone moved to Minnesota for his 
PhD, before joining the faculty at Stanford where he would spend the rest of his career. Kellogg 
completed his master?s and doctorate at Indiana, and then took a faculty position there that he 
held until 1950 when he moved to Florida State University. Maier and Beach both spent time 
early on in Lashley?s laboratory at the University of Chicago, before moving to the University of 
Michigan and the American Museum of Natural History (AMNH), respectively (Beach followed 
Network Analysis of the JCP 81 
Lashley to Harvard to complete his graduate training). A student of Stone?s, Harlow spent his 
entire graduate career at Stanford, before moving to Wisconsin in 1930, where he remained until 
retiring as George Cary Comstock Research Professor of Psychology in 1974. Thus, only five 
institutions were examined in this section: Stanford, Michigan, Indiana, Wisconsin, and the 
American Museum of Natural History. 
Referring to Figure 4 and Table 4, one can see that Wisconsin (d=21, wd-63) was the 
only institution that was top six in both degree and weighted degree. Stanford (d=10, wd=53) 
was just left off the list, but remained one of the most productive institutions on the list. 
Michigan (d=8, wd=35), Indiana (d=8, wd=17) and the Museum (d=5, wd=14) were less 
productive than Wisconsin and Stanford, but were still above the 80th percentile of institutions in 
terms of output in the JCP. All five of these institutions were located closest to the model 
organism of their incumbent psychologists: Stanford, Michigan, and the Museum were closest to 
the rat, Wisconsin was right beside the monkey, and Indiana was located nearby the dog. Maier, 
Kellogg, Harlow, and Beach did not join their respective institutions until after 1930. Thus, I 
once again viewed the network in two separate time periods. 
Institutions in the Early Years (1911-1930) 
The institution network from 1911 to 1930 (Figure 5) was consulted to determine Stone?s 
influence in this period. Stone joined the Stanford faculty in the autumn of 1922 and immediately 
made his mark. The Stanford psychology department had been founded in 1892, when Frank 
Angell, a product of Wundt?s lab in Leipzig, established the laboratory and assumed the position 
of Professor and Director of the Philosophy Department. From 1892 until he retired in 1921, 
only one article was published in the JCP from Stanford; an article by James Rollin Slonaker 
(1912) on the development of an albino rat. Angell, who was a year removed from establishing 
Network Analysis of the JCP 82 
the psychology laboratory at Cornell University, only trained one PhD student during his tenure 
at Stanford: John Edgar Coover. Succeeding Angell in 1922 was Lewis M. Terman, a graduate of 
G. Stanley Hall?s Clark University. He was moved from a professorship in education to head the 
newly formed psychology department (Hastorf, 2004). Terman brought Stone in to serve as the 
resident comparative psychologist, joining a small but prominent faculty of Truman Kelley, 
prominent statistician influential in the development of factor analysis; Walter R. Miles, an 
experimental psychologist with many interests; Edward K. Strong Jr., the well known vocational 
psychologist; and Paul R. Farnsworth, who later became a social psychologist. The arrival of 
Stone invigorated the comparative program at Stanford, as it published sixteen articles on five 
species from 1923 to 1930. Of these sixteen articles, fourteen can be in some way connected to 
Stone either by first authorship, second authorship, or as an acknowledgment by the writer in a 
footnote. The Stanford comparative research program became even more productive post 1930. 
Stone?s research acumen was assured by his supervisor, Lashley, to Terman in 1922: ?In 
research he has shown a good bit of originality, and a very great perseverance showing unusual 
independence. His interest is chiefly in nervous and glandular mechanisms. He gives every 
indication that he will continue to be active in research? (cited in Rosvold, 1955, pp. 326-327). 
Lashley did not falsely advertise his pupil. 
Maier, Kellogg, Harlow, and Beach did not publish under the affiliation of their home 
institution until after 1930, and thus, their influence could not be gauged in this network. 
However, looking at the degrees and weighted degrees of Michigan (d=5, wd=3), Wisconsin 
(d=11, wd=11), Indiana (d=2, wd=3), and the AMNH (d=0, wd=0) in this period allowed us to 
determine the institution?s level of productivity prior to their incumbents arrival. Michigan and 
Indiana researchers were barely active in this period, publishing only three articles each on five 
Network Analysis of the JCP 83 
and two species, respectively. The Wisconsin laboratory, although only publishing eleven 
articles, was highly comparative studying eleven distinct organisms. And the AMNH did not 
publish in this time period. 
Institutions in the Later Years (1931-1950) 
Figure 6 shows the network from 1931 to 1950. Stanford?s comparative research program 
continued to thrive in this period, publishing 36 articles on eight subjects. Stanford?s model 
organism was, like many other institutions, the rat: 36 of the institution?s 53 articles were on the 
rat. Stone was once again the dominant influence in Stanford?s participation in the JCP, directly 
involved in 31 of the 36 articles (thirteen as first author, eleven as second author, and seven 
times acknowledged in a footnote). Stone dominated the comparative psychology program at 
Stanford in a way that no other laboratory head did.26 Of course, much of the success of Stone?s 
program was in large part due to the National Research Council?s establishment of the 
Committee for the Research on Problems of Sex (CRPS), and the Rockefeller funding that 
sustained it. Stone, along with many of his students and collaborators, funded their research with 
CRPS grant money. Stone also became editor of the JCP in 1947 (when the name changed to 
Journal of Comparative and Physiological Psychology), but this did not seem to change his or 
Stanford?s publication patterns. 
Prior to the 1930s, the Michigan laboratory was barely active, publishing only three 
articles on five organisms. In fact, there was no publication in the JCP under the Michigan 
affiliation from 1914 to 1928. This period of inactivity ended in the 1930s with the arrival of 
Norman Maier. During this period, the department was under the headship of John F. Shepard 
(Thurma, 1932). However, the most active Michigan researcher contributing to the JCP was 
Maier, publishing 24 of the institution?s 30 articles. Maier, who took his BA and doctorate at 
26 This, of course, refers only to the research output in the JCP. 
Network Analysis of the JCP 84 
Michigan under Shepard?s supervision, returned to the university in 1931 and immediately 
boosted the department?s research output. Indeed, Maier was singly responsible for 80 percent of 
Michigan?s appearance in the journal, and without him, the department would have been 
stagnant. Further purporting Maier?s influence at the institutional level, Michigan researchers 
were conducting studies on only the human and the rat, the same two organisms that Maier 
favored. The pattern of how often these organisms were studied also mimicked Maier?s research 
program, with 26 studies on the rat and four on the human.    
Similar to Michigan, Indiana was essentially inactive before the arrival of Kellogg in 
1929. The institution?s twelve publications in this later period on seven organisms were, in 
effect, a reflection of Kellogg?s individual research. An article by Alfred F. Lindesmith (1946) 
on chimpanzees was the only Indiana affiliated paper that was not connected to Kellogg. Outside 
of his ten first-authored publications, he co-authored an article on the dog with E.L. Walker. 
With this information in hand, it goes without saying that the dog was the model organism for 
the Indiana laboratory. This was due in large part to Kellogg, but also due to the dog 
conditioning laboratory that was established in 1936. The relationship between Kellogg and 
Indiana provided an interesting scenario that was distinct from the others. Indiana?s research 
output depended on Kellogg?s research and without Kellogg on the faculty at Indiana, the 
institution?s appearance in the network would have been meager. Although this can be seen as 
the dominant influence of Kellogg, it is more a byproduct of his role at Indiana. Benjamin and 
Bruce (1982) have argued that Kellogg was a ?loner? at Indiana, and was not afforded the 
autonomous role as leader of the laboratory he desired. This led to him having only a few 
doctoral students at Indiana, and a rather paltry research program; especially when compared to 
the programs at Wisconsin and Stanford during the same period. The unappealing position he 
Network Analysis of the JCP 85 
found himself in was the reason he took less money to go to Florida State University in 1950. 
There, he abandoned the dog for the porpoise, and was given the leadership role he long desired. 
Wisconsin before Harlow was highly comparative, studying insects such as mosquitoes, 
flies, butterflies, crickets, and beetles, the amphibian salamander, the arachnid scorpion, and 
water creatures such as fish, minnows, plankton, and sea urchin. This pre-Harlow comparative 
laboratory, under the purview of Joseph Jastrow (Cadwallader, 1987) was destroyed by the time 
Harlow arrived in 1930 (Rumbaugh, 1997). Upon his arrival, Harlow began to reshape the 
Wisconsin comparative research program into predominantly a primate research center. Indeed, 
in 1932, Harlow, with his own money and the assistance of his students, converted a house into a 
primate laboratory. Another account claimed that he had a primate laboratory put up on campus 
without the permission of the university; a move that almost cost him his job. But it was in 1953, 
with the support of the university, that he established his primate facility in a former cheese 
factory (Rumbaugh, 1997). This primate facility held important implications in the history of 
psychology. In this period, Wisconsin conducted 37 articles on ten species. None of the earlier 
species studied at Wisconsin were studied under Harlow?s headship. Wisconsin undeniably 
became a center for primate research, conducting experiments on lemurs, orangutans, baboons, 
apes, gorillas, chimpanzees, humans, cats, dogs, and of course, monkeys. The only organisms of 
these ten that Harlow did not study were gorillas, chimpanzees, and dogs. The Wisconsin model 
organism was the monkey by a wide margin (26 of 37 articles published used monkeys). 
Harlow?s influence went beyond this focus on primates, especially the monkey; like Stone, he 
contributed to 32 of the 37 articles published either through first authorship, second authorship, 
or in a supervisory role. An interesting finding was that Wisconsin did not, at any time, study the 
rat; one of the few institutions who could make such a claim. 
Network Analysis of the JCP 86 
The AMNH (d=5, wd=14) in this period was the least active of the five institutions. 
However, this characterization is misleading, as it takes into account only the publications in the 
JCP. The Museum was actually one of the most comparative institutions studying a diversity of 
organisms and a wide range of behaviors (Pettit et al., forthcoming/2015). This was due in large 
part to the intersection of two distinct disciplinary communities: G. Kingsley Noble?s zoology 
and Frank Beach?s neuropsychology which focused on sexual behavior during his time at the 
Museum. Noble?s zoological program centered mostly on courtship behavior in a diversity of 
organisms. Pettit et al. (forthcoming/2015) argued that this exposure to the multispecies biology 
of the Museum influenced a change in Beach, ultimately leading to his condemnation of 
comparative psychology as the study of rat learning. This influence was not unidirectional, 
however, as Beach brought with him to the AMNH a greater emphasis on experimental control 
and quantification (Pettit et al., forthcoming/2015). Beach?s first place of permanent employment 
was the Department of Biology at the AMNH in 1938. In terms of the Museum?s participation in 
the JCP, Beach was the most active, contributing eleven of the total fourteen articles published 
in this journal. Moreover, Beach was the only researcher at the AMNH experimenting and 
publishing on the rat in the JCP. The other three articles focused on the cat, snake, turtle, and 
hamster. Upon the death of G. Kinsley Noble, the department chairman, lobbying by Beach, 
Yerkes, and Lashley saved the department from extinction, turning it into the Department of 
Animal Behavior ? a place many prominent comparative psychologists would make their home. 
The AMNH, thus, developed a distinct culture of comparative psychology (Pettit et al., 
forthcoming/2015). 
It is clear that all five of these authors were highly visible and influential in their 
respective institutions. Although each laboratory had their own distinct characteristics, the five 
Network Analysis of the JCP 87 
comparative psychobiologists shared two similarities: each author?s program of research was the 
reason for the majority of their institution?s publications; and the model organisms of Stone, 
Maier, Kellogg, Harlow, and Beach became the model organism of their institutional home. This 
institutional influence, coupled with their prolific individual contributions to the JCP, articulates 
Dewsbury?s claim that a handful of ?new generation? prominent psychologists helped the 
comparative discipline prosper in the 1930s and 1940s. In this case, these prominent 
psychologists conducted their research in the psychobiology outlined by Yerkes and Dunlap, and 
were integral in continuing in the comparative tradition. 
Network Analysis of the JCP 88 
Chapter Three (1920-1950): Neo-behaviorism and the Journal of Comparative Psychology 
By the time of the controversial affair with Rosalie Rayner that led to his dismissal from 
Johns Hopkins in 1920, Watson found himself on the outside of academic circles, with his 
version of behaviorism being dropped by some and reformulated by others. Indeed, the period of 
1920 to 1950 was dominated by the number of competing learning theories on the ?lawfulness of 
behavior,? that have collectively been termed neo-behaviorism. Like the psychobiologists, neo-
behaviorists were interested in the study of behavior. However, rather than looking at the 
biological processes involved, the neo-behaviorists ? like their predecessors Thorndike, Pavlov, 
and Watson ?believed that the key to a scientific psychology was the study of learning and 
motivation through rigorously objective observational methods. Unlike their predecessors, the 
neo-behaviorists were much more interested in theory, and focused their efforts in trying to 
formalize laws of behavior (Amsel, 1989; O?Donnell, 1985). They were also influenced by 
philosophers Rudolph Carnap (1891?1970), Otto Neurath (1882?1945), and Herbert Feigl 
(1902?1988), who were leaders in the Vienna Circle of logical positivists. The logical positivists 
argued that science and meaningful knowledge can only be produced by physical observations of 
the world; anything else was either analytic or metaphysical nonsense. Thus, any statement made 
about a phenomenon under study must be constructed as a statement derived from physical 
observations (Smith, 1986). This philosophy further separated behaviorism from psychobiology 
because it removed speculations on ?internal? mental operations from their repertoire. Whereas 
psychobiologists viewed behavior in organisms in its entirety (biological, environmental, 
physical, and even mental), neo-behaviorists confined themselves centrally to maze learning in 
white rats (later, conditioning in pigeons), and refused to accept concepts such as thinking, 
reasoning, and unobservable emotions in their vocabulary.  
Network Analysis of the JCP 89 
As the previous chapter assessed Dewsbury?s claims on the comparative discipline, this 
chapter assesses those made by Schneirla and Beach. Schneirla first drew the attention of the 
disciplines practitioners to this overreliance on the rat, but Beach elaborated on it, boldly 
claiming that comparative psychology had disappeared and become behaviorism or the study of 
?rat learning.? To investigate this claim using the network visualization, I shifted the focus 
toward the rat, the de facto model organism of the early neo-behaviorists (Benjamin, 2007; 
Dewsbury, 1984; Benjafield, 2005). In particular, I sought to examine the pattern in which the rat 
rose to become the most widely used species in the entire discipline. Moreover, since neo-
behaviorism benefits from a rich historiography ? many history of psychology textbooks 
dedicate significant portions to this part of the discipline?s history (see Benjamin, 2007; 
Benjafield, 2005) ? determining other hallmarks of the movement was simple. Like Yerkes, 
Dunlap, and Lashley were the ?giants? in their psychobiology, Edward C. Tolman, Clark L. Hull, 
B.F. Skinner, and Edwin R. Guthrie were the four commonly recognized ?giants? in neo-
behaviorism (see Benjamin, 2007; O?Donnell, 1985; DeGrandpr? & Buskist, 2000; Benjafield, 
2005). Thus, I sought to determine their appearance in the network, looking specifically at their 
weighted degree and overall position (degree was not as important since I did not expect these 
predominately rat researchers to have been studying multiple organisms).  
Unlike the psychobiologists, who published frequently in the JCP, these neo-behaviorists 
published more in general periodicals like the Journal of Experimental Psychology, 
Psychological Review, Psychological Bulletin, and The American Journal of Psychology. Thus, 
only Tolman and Hull appeared in the network (Skinner only published articles on laboratory 
equipment in this period). Since the most prominent neo-behaviorists were not the most prolific 
rat researchers in the network, I sought to determine the individuals who were the most closely 
Network Analysis of the JCP 90 
connected to the rodent. To accomplish this, I removed from the network any author who did not 
publish at least ten articles on a single species in order to elucidate the most prominent rat 
researchers. I paid no attention to the number of organisms studied (degree) in this step as the 
majority of neo-behaviorists studied only the rat and unlike their psychobiological counterparts, 
did not employ a comparative approach to ?find? their model organism. Instead, the mounting 
studies conducted on the rat only further cemented its place in learning theory (Logan, 2005), 
and young researchers inherited the animal when entering a behaviorist laboratory.  
Only eight authors remained after the previous step: Maier, Stone, Beach, Karl F. 
Muenzinger, Marion E. Bunch, Robert C. Tryon, Paul T. Young, and Paul S. Siegel. All eight 
researched the rat more than ten times. Maier, Stone, and Beach, characterized as 
psychobiologists and discussed in the previous chapter, were omitted from the list. With the 
remaining five authors, I wrote a brief biography of their academic careers, and examined their 
weighted degree and position within the network. Of course, with such a close connection to the 
rat, I expected that they would be positioned next to its cluster within the network. I argue that if 
these prominent rat researchers submitted to a behavioristic framework, then neo-behaviorism, 
through its connection to the rat, was influential in the journal. This would justify the part of 
Beach?s claim that behaviorism was a rising force within comparative psychology. 
The third and final part examines the institutions most closely connected to the rat. To 
uncover these institutions, I removed all institutions that studied a single organism less than 
thirty times. Thus, only the institutions that produced thirty articles on one organism were 
included. Only six institutions remained: the Yale Laboratories of Primate Biology, the 
University of California, the University of Chicago, Yale University, the University of 
Minnesota, and Stanford University. The YLPB was eliminated from the list because the favored 
Network Analysis of the JCP 91 
organism was the chimpanzee, and also because it featured in a previous chapter. Stanford?s 
connection to the rat, discussed in the previous chapter, was directly linked to Calvin Stone?s 
leadership of the comparative laboratory, and was thus omitted from the list. The four institutions 
that remained all favored the rat by conducting more than thirty articles on the species. This 
close connection indicated the possible presence of behavioristic theory; however, to determine 
if it was indeed present, I further examined the institution?s participation (degree, weighted 
degree) in the journal, and members of the department?s faculty. I argue that the institutions that 
employed the least comparative approach (lowest degree) of these prolific rat research centers 
were most likely to have submitted to a behavioristic approach.  I also purport that the 
institutions that housed the most prominent behaviorists utilized the JCP as an outlet for their 
students? dissertations, and that these dissertations were behavioristically oriented (mostly on 
learning in the rat). This would further prove that Beach was partially correct in pointing out 
behaviorism?s (in the form of rat learning) impact on the comparative discipline.  
In the previous chapters, I looked at the period diachronically since there were two 
generations of psychobiologists. In this chapter, I looked at the period of 1920 to 1950 
synchronically since all the main learning theorists proposed some form of their theoretical 
framework by the 1930s. Like previous chapters, I looked at two different network structures: an 
author-organism dyad; and an institution-organism dyad. With the current construction of my 
argument, I intend to make the case that Beach was correct in claiming that the influence of neo-
behaviorism was vast in the JCP (although not to the extreme point of replacing the discipline), 
and was mostly witnessed through the rise of rat research. I argue that although many 
psychobiologists were studying the rat in equal or greater numbers, the rise of the rat?s usage in 
the 1930s was directly connected to the number of neo-behavioristic theories that surfaced in the 
Network Analysis of the JCP 92 
decade. Furthermore, I purport that many of the most prolific rat researchers in this journal were 
affiliated with the neo-behavioristic scaffold. Finally, I illustrate that although the key neo-
behaviorists were not the most active participants in the JCP, their institutions were among the 
most prolific rat research centers in the period. I contend that the ?factory? approach of these 
institutions ? that is to say, many ?one-and-done? publications and less prolific authors ? were 
indicative of the strong behavioristic research programs built there, and the reality that many 
young scholars inherited the rat as a research subject instead of ?finding? their own model.  
The Rat and the Neo-Behaviorist ?Giants? 
The first network I looked at displayed the relationship between author and organism 
from 1920 to 1950 (Figure 10) and was oriented based on weighted degree. In other words, the 
emphasis was placed on the number of studies conducted. This network consisted of 654 nodes 
and 744 edges. The second network displayed the connections between institutions and 
organisms for the same period, effectively replacing the authors from the dyad (Figure 11). Since 
there were more researchers than institutions, there was less data in this network: 238 nodes and 
403 edges. The nodes in this case represented organisms and institutions. In many ways, the most 
salient aspect of these networks, the rat, was perhaps the most unsurprising. Many historians 
have written about the neo-behaviorists? (and non neo-behaviorists, for that matter) preference of 
the rat as an object to study learning (Dewsbury, 1984; Beach, 1950; Benjamin, Jr., 2007; Logan, 
2005). Thus, the fact that the rat featured so prominently in both networks was not a revelation. 
However, the rat represented a gateway into the influence of neo-behaviorism in the JCP, and 
was therefore analyzed further. 
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94
Network Analysis of the JCP 95 
Rattus Norvegicus 
Viewing Figure 10, one can see that rats were the subject of more studies than any other 
organism in the JCP at the time. The rat (344) was studied by nearly three times as many 
researchers than its nearest counterpart, the human (121). Since two organisms cannot be 
connected, we know that 344 authors had published at least one study using the rat as the subject. 
Moving to Figure 11, it was apparent that more institutions were connected to the rat (99) than 
any other organism, including the human (74). Thus, in both networks, the rat possessed the 
highest degree, meaning more authors and institutions were studying the rat in the JCP than any 
other species. Moreover, the rat, with a weighted degree of 718, was studied more than four 
times as much as the human (175).  
The visual and quantitative domination of the rat aligns historically with neo-behaviorism 
and learning theory. Some have argued that the use of the rat for research purposes was an 
accidental event (for example, Beach, 1950; Lockard, 1968). However, Dewsbury (1984) argued 
many of the earliest learning theorists emphasized selecting an organism in which studying 
learning would be appropriate (for example, Small, 1901; Miles, 1930). Thus, the rat was chosen 
specifically for its natural propensities and capacity with which to study learning. Furthermore, 
the relatively low cost and easy maintenance of colonies of rats contributed to the spread of the 
species as animal subjects. Thus, less prolific and smaller institutions were more likely to use the 
rat as a test subject due to cost effectiveness. As more researchers studied the rat, the bank of 
available knowledge on the animal grew, further cementing the use of the organism in studies on 
learning.27 But the use of the rat was not confined to learning studies; the rat became a ?standard 
organism? in related fields such as physiology and neurology, and also was a popular choice 
amongst psychologists studying development (Logan, 2005; Pettit et al., forthcoming/2015). The 
27 Skinner?s pigeons also became a popular subject choice, but this did not occur until much later. 
Network Analysis of the JCP 96 
rat?s atricial pattern of growth (slow and gradual development) made them amenable subjects to 
learning and developmental studies; psychologists were able to witness development unfold 
under controlled conditions (Logan, 2001). In 1906, Henry H. Donaldson began a very 
successful breeding program at the Wistar Institute which populated psychology and medical 
laboratories across North America (Pettit et al., forthcoming/2015). The problems many have 
identified with the spread of rats as an object of study generally stemmed from the researchers 
disregard for the natural propensities and limitations of the rat as a subject, leading to 
inappropriate generalizations. As Dewsbury (1984) explained, rats should not be classified as a 
good or bad research subject, but instead should be classified as suitable for some kinds of 
research, and unsuitable for other kinds. 
The rat?s prominence as depicted in the networks and historically is undisputed. 
However, this synchronic view of the journal did not account for the exponential growth of the 
rat after 1930 that was seen in the previous chapter. To help understand this growth and when it 
was greatest, I broke the network down into three periods covering three separate decades: 1920 
to 1929; 1930 to 1939; and 1940 to 1949.  
Figure 12 shows the network from 1920 to 1929. In this network, two large clusters 
formed; the largest cluster around the human, and the slightly smaller one around the rat. 
According to the network, the rat was only studied 69 times by 42 different researchers, whereas 
the human was studied 80 times by 57 distinct researchers. The network from 1930 to 1939 was 
depicted in Figure 13. A transformation occurred in this network: the rat cluster dramatically 
increased in size, dominating the network, while the human cluster decreased slightly. The rat 
was studied nearly 4.5 times more in this decade than the last, with 306 articles published. 
Moreover, 153 researchers conducted experiments on the rat in this decade, 3.5 times more than  
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Network Analysis of the JCP 100 
the 1920s. Interestingly, the human could not sustain its growth from the previous decade, falling 
to only 64 studies by 48 researchers. Figure 14 displayed the final network covering the decade 
from 1940 to 1949. This decade resembled the previous decade in terms of the rat?s use as a test 
subject. A total of 307 articles by 162 researchers essentially demonstrated that although the rat 
did not grow much, it maintained its popularity throughout this decade. The human, on the other 
hand, continued to drop, with only 26 studies by 23 researchers. The chimpanzee had even 
eclipsed the human in this decade in terms of output with 29 articles by 17 authors. Thus, it was 
apparent that from the 1930s on, the rat was the most popular test subject by a large margin. 
However, although the rat was studied more often and by more researchers in the 1940s, the 
species experienced its major growth in the 1930s. A plausible explanation for this growth might 
have been the emergence of the theoretical frameworks of the major neo-behaviorists in the 
1930s. 
Tolman, Guthrie, Hull, and Skinner 
All four of these behaviorists published some form of their theories in the 1930s: Tolman 
was the first, publishing his textbook Purposive Behavior in Animals and Men in 1932; Guthrie 
and Hull both published on their theories in 1935, Guthrie with his book entitled The Psychology 
of Learning and Hull?s article in Psychological Review ?The Conflicting Psychologies of 
Learning: A Way Out?; and Skinner was the last of the bunch, his textbook, The behavior of 
organisms: An experimental analysis, printed in 1938. Each one of these theorists or ?system-
builders? (Krech, 1959) also favored the rat as their test subjects; however, Skinner eventually 
moved from the rat to the pigeon (Rutherford, 2009; Benjamin, 2007). Although all were 
historically prolific, only Tolman and Hull appeared in the network;28 albeit not as often as one 
might expect. This was an expected finding. Guthrie, although publishing extensively in his early 
28 Skinner published articles describing apparatus, and thus, did not qualify as a substantive article. 
Network Analysis of the JCP 101 
years as a philosopher, was much less prolific as a behaviorist where he only published three 
texts on human behavior (Clarke, 2005). Skinner did not attain his level of publication 
prominence until the 1960s (Benjamin, 2007). Tolman and Hull were much more active 
individually, and at the laboratory level in this era. 
Figure 15 depicts the author-organism network from 1920 to 1950 with Tolman and Hull 
circled. Both authors were located close to the rat node, but unlike their psychobiologist 
counterparts ? whose comparative work closely matched the original goals of the JCP ? the neo-
behaviorists were inconspicuously nestled within a large group of rat researchers. Tolman was 
the more active of the two by a slight margin: Tolman published five first-author articles on the 
rat and Hull contributed four rat experiments. Their weighted degrees made them moderately 
active in this journal and their degrees of one aligned with what was to be expected. Alone, the 
paucity of this output might suggest that these individuals were not active contributors to the 
JCP. However, Tolman and Hull were actively publishing in a number of journals at the time ? 
Journal of Experimental Psychology, Psychological Review, Psychological Bulletin, The 
American Journal of Psychology, the Journal of Abnormal and Social Psychology, the Journal of 
Educational Psychology, and the Journal of Philosophy ? and the JCP was among the most 
frequent of their chosen outlets. In terms of influence to the comparative discipline, Tolman and 
Hull exerted most of their influence through their theoretical frameworks and the output of their 
psychological laboratories (discussed in a later section). 
102
Network Analysis of the JCP 103 
Purposive Behaviorism and the Hypothetico-deductive Method 
The purposive behaviorism of Tolman and hypothetico-deductive method of Hull shared 
some similarities. Both frameworks utilized the white rat as a test subject, emphasized the 
importance of the objective study of overt behaviors, and adhered to some form of a stimulus-
response relationship. However, the similarities stopped there, as both men advocated opposing 
theories on behavior. 
Edward Chace Tolman (1886-1959) received his doctorate at Harvard under Hugo 
M?nsterberg and Robert Yerkes before moving to the University of California, Berkeley in 1918, 
to spend the rest of his career. Tolman argued for a molar or holistic approach towards the study 
of learning and behavior. For him, behavior was purposive; indeed, his most important textbook, 
published in 1932, was titled Purposive Behavior in Animals and Men. He believed that behavior 
did not just occur spontaneously, but rather, was directed towards a particular goal.  
Further separating him from his many behaviorist brethren, Tolman believed that he had 
reduced cognitive concepts (purpose, mental maps, etc.) to behaviorial terms, and thus retained 
cognitive processes as the underlying mechanisms for this purposive behavior. Tolman could not 
understand how anyone who had witnessed rats in a maze could argue against the purposive 
nature of the rat?s behavior. Tolman believed that rats had cognitive maps or spatial 
representations of their environment that led to effective functioning. He argued that as an 
animal (rat) attained experience of their environment, they built up expectancies, which in turn, 
acted as a determinant in how the animal would respond in the future. Tolman (1951) 
demonstrated his theory of cognitive maps by testing two groups of rats in a plus shaped maze. 
For the one group (response learners), the rats had to always turn right to receive food no matter 
which arm they started off in. The other group (place learners), were always fed in the same 
Network Analysis of the JCP 104 
place regardless of which arm they started off in. Thus, the response learners had to learn to turn 
right to be fed, and the place learners had to learn to go to the same part of the maze on each 
trial. Tolman found that the place learners learned the maze more quickly than the response 
learners, indicating the use of cognitive maps as a tool to guide the rats learning.  
Tolman also objected to Watson?s approach of a strict stimulus-response in 
understanding behavior. The Berkeley professor did not believe that psychology should be 
limited to such a simplistic framework, and called for the recognition of intervening variables 
that ?intervened? between the stimulus and the response. Cognitive processes were Tolman?s 
examples of an intervening variable, and so long as they were supported by observations, they 
could be scientifically respectable.  
Tolman also questioned the role of reinforcement in learning. Hull and B.F. Skinner both 
believed that reinforcement was necessary for learning to occur. Tolman disagreed, citing his 
studies on latent learning as an example of a contradiction. In one particular study, Tolman 
(1948) placed a rat in a maze and did not present any food. Even without a reinforcer, Tolman 
argued that the rat still began to construct a cognitive map of the maze so much so that when 
placed in the maze with food present, the rat did better than an entirely na?ve rat. 
Clark Leonard Hull (1884-1952) earned his doctorate in 1913 under the mentorship of 
Joseph Jastrow, Daniel Starch, and V.A.C. Henmon at the University of Wisconsin. He remained 
at Wisconsin until 1929, when he left his teaching post to join the prestigious Rockefeller funded 
Institute of Human Relations at Yale University. He held this new position for the remainder of 
life. Much of Hull?s early work focused on aptitude testing and hypnosis, but it was his theory of 
behavior on which he became the most cited psychologist of his time (Benjamin, Jr., 2007).  
Network Analysis of the JCP 105 
Of all the neo-behaviorists, Hull was the most ambitious in formalizing laws of behavior, 
and he believed he had determined the fundamental laws of learning and habit formation that 
underlay the behavior of all humans and animals. Hull (1952) conceptualized his theory as 
follows: 
I came to the definite conclusion around 1930 that psychology is a true natural science; 
that its primary laws are expressible quantitatively by means of a moderate number of 
ordinary equations; that all the complex behavior of single individuals will ultimately be 
derivable as secondary laws from (1) these primary laws together with (2) the conditions 
under which the behavior occurs; and that all the behavior of groups as a whole, i.e., 
strictly social behavior as such, may similarly be derived as quantitative laws from the 
same primary equations (Hull, 1952, p. 155). 
Hull?s faith in the lawfulness of human behavior would eventually lead to the demise of his 
theory. 
According to the fundamental law Hull believed guided behavior, an unconventional 
stimulus could bring about a response as long as it was associated, either temporally or in nature, 
with the stimulus that usually elicits the response. This effect had previously been noted by 
Pavlov when his dogs salivated at the unconventional stimulus (ringing bell) after it had been 
paired with a natural stimulus that elicits salivating (food). Similar to Pavlov?s classical 
conditioning, Hull also theorized that learning was not all or nothing, but instead occurred 
incrementally. The animal gradually learned to respond to all the aspects of a positive stimulus or 
to avoid a negative stimulus, and thus, stimuli could be engineered to precisely control the 
forming of particular habits. Unlike Tolman, Hull?s theory of behavior was mechanistic, and 
thus, removed any talk of consciousness, the soul, or free will. Hull, who at one point hoped to 
Network Analysis of the JCP 106 
be an engineer, designed working machines that demonstrated the principles of conditioning 
reflexes, further purporting the mechanistic functioning of human behavior. Moreover, as his 
own conceptualization of his theory suggests, Hull reduced behavior down to a series of complex 
mathematical equations, and his 1943 book Principles of Behavior: An Introduction to Behavior 
Theory was filled with them (Hull, 1943; Amsel, 1989; Amsel & Rashotte, 1984; Benjamin, Jr., 
2007; O?Donnell, 1985).  
To test the validity of his grand theory, Hull used what he called the hypothetico-
deductive method. Inspired by the natural philosopher, Isaac Newton, and his scientific certainty 
of knowledge, Hull sought to establish his laws of behavior strictly on firm observational and 
experimental techniques. His method began by stating a postulate or series of postulates from 
which testable hypotheses could be deduced and tested experimentally, which in turn lead to 
either a confirmation of the hypothesis or a disconfirmation. Upon a disconfirmation, the 
postulate would be modified so that a new hypothesis is deduced from the revised postulate. This 
process continued until the hypothesis is experimentally and observationally proven.  
Hull also differed from Tolman on his views of the importance of reinforcement in 
learning. Without reinforcement, Hull believed learning could not occur. At the crux of his 
theory of reinforcement was the idea of drive reduction. That is to say, certain bodily needs such 
as hunger, sex, thirst, oxygen, etc., would govern how an organism behaves; if the hunger drive 
is strong enough, the organism will seek out food to engage in feeding behavior to reduce that 
drive (Hull, 1943). This reduction in drive served as reinforcement, ensuring that the behavior is 
repeated in similar situations. Moreover, reinforcement was the key to the development of habit 
strength, a concept that Hull used to describe the association between a stimulus and a response. 
The higher the number of reinforcements of a particular association, the more the habit strength 
Network Analysis of the JCP 107 
would grow. Habit strength, essentially, was the main indicator of the strength of learning 
(Benjamin, Jr., 2007). 
Tolman?s theory of behavior was ahead of his time and thus, the psychological 
community responded better to Hull?s theory. Historians believed this to be a byproduct of 
Tolman?s use of cognition in a time when psychology was trying desperately to rid itself of any 
ties to consciousness. However, Tolman?s laboratory remained one of the most productive rat 
research centers of its day that also contributed to the development of a behavioral genetics sub-
discipline. Moreover, in the 1960s and 1970s, when psychologists were once again talking about 
consciousness, Tolman?s ideas were rediscovered and found to be extremely important. Some of 
these ideas were the demonstration of latent learning, the concept of cognitive maps, the 
characteristics of response and place learners, and the distinction between performance and 
learning. For Tolman, performance was the observable behavior, and learning was the internal 
state. Thus, one could not directly observe learning, but could infer it based on the performance 
(behavior) of the animal (Benjamin, Jr., 2007; Dewsbury, 1984; Amsel, 1989; Tolman, 1922). 
The very nature of Hull?s program of research meant that he developed many diverse 
constructs; only a few of which were mentioned in this section. Hull created a psychology theory 
of behavior that has yet to be matched; one that allows researchers to generate testable 
hypotheses. His theory was most popular in the 1940s. And because he created ?an industry in 
experimental psychology? (Benjamin, Jr., 2007, p. 148), two decades worth of doctoral students 
had no issues in finding testable hypotheses on which to base their research. Most of these 
dissertations were learning studies on the rat. The psychological literature was filled with Hullian 
theory, making him the most cited psychologist of his time: ?during the decade 1941-1950 
approximately 40 percent of all experimental articles published in the Journal of Experimental 
Network Analysis of the JCP 108 
Psychology and the Journal of Comparative and Physiological Psychology included references 
to his work? (Amsel & Rashotte, 1984, p. 2). Inevitably, Hull?s belief in the lawfulness of 
behavior was his undoing. As Webster and Coleman (1992) have explained, ?Hull?s impact and 
subsequent decline [were] inevitable outcomes of the programmatic nature of [his] behavior 
theory? (p. 1063). Even though Hull?s theory was eventually disproven, historians acknowledge 
his importance in establishing scientific rigor in psychology (Mills, 1998).   
Tolman and Hull were two of the most influential figures in all of psychology?s history. 
Individually, the network failed to depict the influence of these two neo-behaviorists. However, 
it seems likely that their frameworks were largely responsible for the rise of the rat as test 
subjects in the JCP in the 1930s and 1940s. Moreover, as will be shown in the latter portion of 
this chapter, the University of California and Yale?s Institute of Human Relations were highly 
productive rat research centers under the headship of Tolman and Hull. Thus, unlike in the 
previous chapter, where the psychobiologists themselves were highly influential nodes, the 
influence of the major neo-behaviorists was seen through the rise of the rat as a test species, and 
the adoption of a neo-behavioristic framework in the JCP. To determine the influence of their 
theory on the comparative discipline, I examined the theoretical affiliation of the authors most 
closely connected to the rat. 
?The Rat Pack? 
The next step in determining the influence of behaviorism (as seen through the 
frameworks of the major neo-behaviorists) required eliminating from the network any individual 
who did not study the rat at least ten times to elucidate the most prolific rat researchers.  
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109
Network Analysis of the JCP 110 
As was mentioned earlier, eight individuals were left (Figure 16) with only five relevant to the 
chapter: Karl F. Muenzinger (d=3, wd=13),29 Marion E. Bunch (d=2, wd=16), Paul S. Siegel 
(d=1, wd=12), Robert C. Tryon (d=1, wd=10), and Paul T. Young (d=1, wd=11). These five 
represented the most prominent rat researchers in terms of quantity of publications. Muenzinger, 
Bunch, and Siegel were considered ?dust bowl neo-behaviorists? since each focused on 
empirical observation and data collection while adhering to a neo-behavioristic framework. 
Tryon was a student of Tolman?s, and although somewhat of a ?dust bowl neo-behaviorist? 
operating under Tolman?s framework, his contribution to psychology went far beyond his 
association with the prominent neo-behaviorist. And Young was the only one that did not adhere 
to a behavioristic framework, but instead, was a Titchenerian Structuralist. Thus, it appeared that 
four of the most prominent rat researchers in the network were indeed influenced by the neo-
behavioristic theories of the day, providing support for Beach?s claim. Yet, several rat 
researchers, including Beach himself, did not adhere to neo-behaviorism. 
?Dust Bowl Neo-Behaviorists? 
The reason I characterized Muenzinger, Bunch, and Siegel as ?dust bowl neo-
behaviorists? instead of the more common ?dust bowl empiricist? was twofold: similar to a ?dust 
bowl empiricist,? all three focused strictly on empirical observation with no attempt at building 
their own theoretical framework; however, in contrast to a ?dust bowl empiricist,? these 
scientists were not staunchly atheoretical, and instead, each operated under the neo-behavioristic 
umbrella. This was in stark contrast to Tolman and Hull who were two of the most recognized 
system-builders in the history of learning. Muenzinger aligned himself with Tolman?s purposive 
behaviorism (Krech, 1959). Contrarily, Bunch and Siegel did not submit to any single 
29 (Degree, weighted degree) 
Network Analysis of the JCP 111 
framework, but rather conducted their research under the auspices of the greater neo-behaviorist 
umbrella (Vanderplas, 1997; Pate & Fowler, 2005).  
Karl Friedrich Muenzinger attained his doctorate at the University of Chicago in 1918. In 
1923, Muenzinger took up a faculty position at the University of Colorado in Boulder and by 
1928, he was promoted to Associate Professor. It was in this year that Muenzinger began 
publishing in the JCP. Muenzinger was raised to the full rank of Professor in 1938, the year he 
ceased publishing in the JCP. Muenzinger (d=3, wd=13) published thirteen papers on three 
different organisms in the JCP: guinea pigs, humans, and rats. His first two articles (1928, 1929) 
were on habit formation in guinea pigs. He then moved on to study tone discrimination in rats 
(1931) and electric shock thresholds in humans (1932). The paper on humans was Muenzinger?s 
attempt to standardize electric shock intensities so that they could be used on other animals, in 
his case, rats. The remainder of his articles in the JCP dealt with vicarious trial and error (VTE) 
discrimination learning in rats, which he preferred due to his interests in learning theory and 
systematic psychology.  
Krech (1959) characterized Muenzinger?s work as ?science oriented? rather than 
?Muenzinger oriented?; his work was mostly recognized for its empirical findings, not how it 
contributed to building or sustaining a theory. Muenzinger?s work aligned closely with Edward 
Tolman?s theoretical framework, of whom he was a great admirer. Indeed, Muenzinger ascribed 
the theoretical backbone of his VTE studies to Tolman. Krech also cited his predisposition as 
another facet for why Muenzinger did not bother working out his own system. As a thorough 
researcher, Muenzinger was more concerned with answering his original research question 
through rigorous experiments and replications rather than conducting single superficial 
experiments to merely ?make his point,? a trait indicative of the hit-and-run style that 
Network Analysis of the JCP 112 
characterized the experimental work of many system builders (however exceptional the odd 
successful hit). 
Marion E. Bunch undertook his undergraduate studies at the University of Kentucky, 
taking his BA degree in 1925. From there, he moved to St. Louis, Missouri, where he graduated 
with an MA degree at Washington University in 1926. Immediately thereafter, he was offered a 
position as an instructor by then department chair, John Whitely, at the urging of Bunch?s 
supervisor, John McGeoch. He spent the next eight years teaching and conducting research at 
Washington University as an MA. His first publication in the JCP, in 1928, was a study on the 
effects of electric shock on maze learning in humans. However, Bunch was mostly concerned 
with learning, motivation, memory, and perception in rats, and how these processes contributed 
to the adaptive aspects of the organism. Bunch (d=2, wd=16) conducted studies on two 
organisms, humans and rats. Of the sixteen articles, eleven were on the rat, and five on the 
human. During his time at Washington University, Bunch spent his summers at the University of 
Chicago studying with Harvey Carr; a member of the functionalist school who supervised 
Bunch?s doctoral degree in 1934. Bunch?s work characterized the program of research he 
advocated which included learning, memory retention, transfer of training, perception, 
motivation, and later on, aging and gerontology. By 1949, Bunch was offered and took the 
position of chair of the psychology department at Washington University; a position he held for 
over twenty years. It appeared that although Bunch studied under the functionalist, Harvey Carr, 
he conducted his own program of research that fit under the behavioristic umbrella and, like 
Muenzinger, he did not seek to build his own theory (Vanderplas, 1997). Much of Bunch?s later 
work came at a time when behaviorism relinquished its hold as the governing psychological 
Network Analysis of the JCP 113 
framework in learning and motivation; a time when psychologists were once again able to write 
and speak about consciousness.  
Paul Shafer Siegel studied English as an undergraduate, taking his bachelor?s degree in 
1938 from the University of Richmond. Switching over from English to psychology, Siegel 
received his MA at Duke University in 1942. It was at Duke that Siegel found his two greatest 
influences, his classmates Sigmund Koch and Edward Stainbrook (Pate & Fowler, 2005). Since 
the Gestalt approach was dominant at Duke during the time Siegel was there, his early research 
on the Von Restorff effect30 was based upon Gestalt principles. He then moved to the University 
of North Carolina where he received his PhD under Robert Wherry in 1944 (Pate & Fowler, 
2005), before taking a professorship at the University of Alabama. What is interesting about 
Siegel?s (d=1, wd=12) contributions to the JCP (during the period of 1920-1950), was that they 
all came between the years 1943 and 1950. All twelve of his articles were on the rat. Not only 
was Siegel one of the most active rat researchers of this time, he was perhaps the most active 
researcher in this eight year period.  
Siegel?s primary research interests laid in learning and motivation. Although he was 
influenced early by Gestalt theory, he quickly adapted his research to include the dominant 
behavioral theories. In fact, his first few articles on drive shift, the effect of electroshock on maze 
learning, habit strength, and extinction (Siegel, 1943; 1943; 1946; 1946; 1947; 1947), relied on 
the previous work of four established neo-behaviorists: Hull, Muenzinger, Skinner, and Tolman. 
He moved on to the investigation of audiogenic seizures, the effect of emotionality on food and 
water intake, and the importance of the dark-light cycle. As behaviorism?s hold on learning 
theory began to wane in the 1950s (DeGrandpr? & Buskist, 2000), Siegel left his research on rats 
30 The Von Restorff effect is named after psychiatrist and pediatrician, Hedwig von Restorff. Also termed the 
isolation effect, it asserts that something unusual is more likely to be remembered (Gumenik & Levitt, 1968). 
114
Network Analysis of the JCP 115 
and began studying behavior in ?retardates,? investigating in these research participants 
discrimination learning and incentive motivation. Prolific though he was in terms of the quantity 
of his contributions, Siegel was mostly remembered as a mentor, teacher, and administrator (Pate 
& Fowler, 2005).  
Muenzinger, Bunch, and Siegel were content to accept and work under the dominant 
disciplinary paradigm of the era, accepting the behavioristic emphases as scientific truth and 
assimilating their own research into this framework. However, although they were ?dust bowl 
empiricists,? all three were highly productive in the JCP and influential to the comparative 
discipline. Figure 17 depicts all five rat researchers circled in the network from 1920 to 1950. 
Looking particularly at Muenzinger, Bunch, and Siegel, all three were positioned closest to the 
rat in the least populated side of the cluster, which was in contrast to the positioning of Tolman 
and Hull within the mass of rat researchers. Their close connection to the rat also positioned 
them near the middle (or main part) of the network; the rat cluster was the most dominant so it 
made up the majority of the overall network. Muenzinger connected the rat, human, and guinea 
pig clusters, but was closest to the rat. Bunch was a mediator between the rat and human cluster. 
His five articles on the human pulled him further from the rat and closer to the human than the 
other two. Siegel, who was connected only to the rat, was the closest of the three to the dominant 
rat cluster. Thus, ?dust bowl empiricists? or not, these neo-behaviorists were highly influential in 
the JCP. 
Robert Choate Tryon 
Tryon spent his entire career at the University of California at Berkeley; first as an 
undergraduate, receiving his BA in 1924; then as a graduate student, taking his doctorate under 
Tolman in 1928; then as a National Research Council fellow for two years; and finally as faculty 
Network Analysis of the JCP 116 
member of the psychology department in 1931. The only time he left Berkeley was for a short 
period in which he contributed to the war effort, serving as deputy chief of the planning staff of 
the Office of Strategic Services in Washington.  
Tryon?s contribution to psychology began as early as graduate school. Working alongside 
Tolman and Lloyd Jeffress, he developed an apparatus that automatically recorded animal 
behavior in a laboratory setting; arguably the first of its kind. His dissertation, ?Individual 
Differences at Successive Stages of Learning,? in 1928, was a landmark study in animal behavior 
in which he was able to measure individual differences in rat behavior with unparalleled degree 
of reliability. By melding statistical reliability and measurement with objective behavioral 
observation, Tryon succeeded in establishing a new precedent for future psychologists. He 
continued the line of inquiry established in his dissertation throughout his career. 
In 1919, Tolman began a large-scale research project on inheritance in rats using a grant 
of $105 that he received from the Board of Research at the University of California. Specifically, 
he was granted the funding ?for the study of inheritance of unusual ability in learning as 
exhibited by lower mammals.? This extensive project was the first of its kind that bred distinct 
lineages of rats chosen specifically for their maze performances in order to determine the genetic 
component of maze learning. He presented his data from this project in his article ?The 
Inheritance of Maze-Learning Ability in Rats? in 1924 in the JCP. Although this was 
groundbreaking research, it was clearly just the beginning of an ongoing research program. 
The study began with 82 rats (the initial generation), each of which was subjected to a 
maze with four choice points. Their performance on the maze was measured by number of errors 
committed, perfect runs, and the time it took to complete a trial. Male and female rats that 
performed the best on the maze were mated as were the male and female rats that performed the 
Network Analysis of the JCP 117 
worse, starting a maze-bright strain and a maze-dull strain, respectively. The offspring of these 
rats (F1 generation) were then mated in a similar fashion to that of their parents, leading to a third 
generation (F2) of maze-bright and maze-dull rats. Tolman found that the F1 generation of maze-
bright rats performed better than the initial generation, but the F2 generation did not perform as 
well at the F1 rats. Furthermore, the F2maze-dull rats performed about as poorly as the 
F1generation. Tolman was unsure as to why this was the case, noting the age of testing, nutrition, 
inbreeding, and environmental conditions as possible reasons. In any case, Tolman adopted a 
philosophy of ?learning from one?s mistakes,? and set out to construct a more rigorous approach 
to the research (Innis, 1992). 
Tryon, who had enrolled as a graduate student in 1924, possessed unique skill and 
interest in genetics and statistics ? two proficiencies that were invaluable to work on the 
inheritance project. Naturally, Tolman was eager to get him involved in the project. From 1924 
till the time he defended his dissertation in 1928, Tryon, along with others, worked on the 
problems that arose from the original inheritance project.31 By the time that Tryon initiated the 
decisive study in 1927 ? a study which spanned over a decade and included more than 20 
generations of maze-bright and dull rats ? these problems had been rectified.32 
By 1927, Tryon had essentially taken control of the inheritance project. Tryon continued 
this line of research for over a decade and more than 20 generations. However, he noted that no 
further divergence of populations occurred past the eighth generation (see Tryon, 1940; 1942). 
Tryon?s importance to the success of the inheritance project cannot be understated. In fact, some 
31 The problems were outlined succinctly by Innis as ?(a) the reliability and validity of the measures of maze 
learning, which entailed consideration of both the adequacy of statistical treatments and the generality of the 
findings from a particular maze; (b) the nature of the initial subject population and the method of selecting mates in 
future generations; and (c) the control of the environmental variables, such as living conditions, diet, and handling? 
(Innis, 1992, p. 193). 
32 For a more detailed account of this historical event and how each problem was solved, see Innis, 1992. 
Network Analysis of the JCP 118 
have credited him as the pioneer of behavior genetics, noting that the inheritance study he 
undertook was the first successful study on the genetic basis of maze learning, which established 
the sub-discipline of experimental behavior genetics (Krech, Crutchfield, &Ghiselli, 1969). His 
importance to the inheritance project was most aptly displayed when Tolman had leveraged his 
own offer from Harvard (something he had desired as a young professor at Berkeley) to obtain 
an assistant professorship for Tryon at California in 1931 ? a position he held until his death in 
1967 (Innis, 1992).  
It goes without saying that Tryon (d=1, wd=10) was a neo-behaviorist, or, at least a 
Tolmanian neo-behaviorist, and thus, his work was strongly influenced by its theoretical 
framework. He contributed ten articles on the rat to the JCP. This close connection positioned 
him in a similar manner to Siegel in the network (Figure 17): close to the rat and the center of the 
network, and in the least populated side of the cluster. Beyond his influence in the JCP, Tryon?s 
work established a new field of behavior genetics ? for which he and his student, Jerry Hirsch, 
provided the name (Hirsch & Tryon, 1956) ? that flourished until Tryon took up his other 
interest, statistics, in the form of cluster analysis.  
Structuralist in a Behaviorist Era 
The final rat researcher indicated by the network was Paul Thomas Young. Young, 
completed his undergraduate degree at Occidental College, received his MA at Princeton, and 
took his doctorate in 1918 at Cornell. Young acknowledged himself as a product of Titchenerian 
structuralism (Young, 1978); one of the few comparative psychologists who could make that 
claim. His dissertation (Young, 1918) sought to determine whether or not pleasantness and 
unpleasantness could be experienced simultaneously. He argued that reports of ?mixed feelings,? 
in this instance, were vague, as they blurred the line between the meaning (cognitive) and the 
Network Analysis of the JCP 119 
feeling (affective) aspects of experience. He went on to say, ?My doctoral thesis established two 
principles that I believe are valid. First, there is a genuine difference between meaning 
(cognitive) and feeling (affective). Second, when gut feelings of definite sign (positive or 
negative), intensity, and duration are experienced they are not felt simultaneously. P and U are 
incompatible, antagonistic, dynamically opposed? (Young, 1978, p. 42). This line of inquiry 
defined Young?s research for the remainder of his career.  
Young?s thesis relied on introspective procedures on human subjects. His research was 
risky, coming at a time when psychology was moving away from the ?mentalistic? aura of 
structuralism and towards the study of objective behaviors. Young acknowledged these 
competing views of the discipline when describing the controversy between his supervisor, 
Titchener, and Watson over the definition and methods of psychology: ?Watson regarded 
psychology as an objective biological science. He spurned the introspective method. Titchener 
regarded psychology as an independent science based on direct observation of human 
experience? (Young, 1978, p. 42).  
Upon receiving his PhD, he moved to the University of Minnesota for a brief stay, before 
taking a position at the University of Illinois that he held until he retired in 1960. His early 
research at Illinois was a continuation of his graduate work. He spent his sabbatical in 1926 in 
Berlin, working with the likes of K?hler, Wertheimer, Lewin, and other Gestalt psychologists, 
focusing on the physiology of pleasantness and unpleasantness. His work in Berlin led to his 
change in method and his substitution of the rat for the human. He describes the switch himself 
in his final journal article: 
I decided to study the likes, dislikes, and preferences of rats for different kinds of food. 
The subjects were three male rats. The apparatus was an open table covered with 
Network Analysis of the JCP 120 
wrapping paper. The food objects were grains of wheat, oats, corn, and barley purchased 
on the local market. Several kinds of enclosure were tried for presenting pairs of grains 
simultaneously. 
These early experiments showed that rats are uniform in the preferences they develop. 
Test foods arrange themselves into hierarchies or transitive series from low to high 
acceptability. The study demonstrated that preferential behavior can be studied 
objectively with animals. When I returned to Illinois I continued with a series of studies 
on food preferences, appetites, and dietary habits (Young, 1978, p. 43). 
These experiments were the first of a steady stream that would come out of the Illinois 
laboratory for the next 42 years. Eleven of those studies were published in the JCP by Young 
using rats. His ensuing experiments on the preferential behavior of rats served to solidify and 
support his theoretical position that hedonic variables influenced behavior. The most important 
assertion of Young?s theory was that pleasantness and unpleasantness had a neurophysiological 
basis that could be objectively studied; an assertion that was not accepted until the pioneer study 
of Olds and Milner (1954) that utilized electrical stimulation on the septal region of the rat?s 
brain.  
Although Young?s research yielded congruent and non-contradictory results with 
experiments from differing viewpoints (subjective experience, objective animal behavior, 
neuropsychology), he found himself on the wrong side of the dominant behavioral emphases of 
the day. Indeed, O?Kelly (1979) argued that Young?s association with the ?mentalistic aura of 
dead structuralism? and his promotion of the ?hedonic dimension,? largely led to the inevitable 
outcome ?that most investigators in this field have neglected, ignored, or denied [his work?s] 
relevancy? (O?Kelly, 1979, 552). This particular case study further emphasized the influence of 
Network Analysis of the JCP 121 
neo-behaviorism in the journal. Although Young was prolific in output and was the closest of 
any author to the rat (see Figure 17), his work never received the attention it deserved because it 
ran counter to the accepted behavioral theories of the day.  
Before concluding this section, some important findings need to be discussed. First, 
including Maier, Stone, and Beach alongside Muenzinger, Bunch, Siegel, Tryon, and Young, one 
sees that the plasticity of the rat as a test subject made it a popular model within competing 
research programs. This variability made it a necessity to ?look closer? in order to determine the 
theoretical frameworks of the authors. Second, the low degrees of the neo-behaviorists 
represented a generation of psychologists that ?inherited? their model organisms from their 
supervisors (e,g,. Tryon ?inherited? the rat once joining Tolman?s laboratory). Although only 
four of the five rat researchers were characterized as behaviorists, these case studies indicated a 
pattern in which many ?dust bowl? researchers conducted their studies under the sponsorship of 
neo-behaviorism. These findings all support Beach?s argument that behaviorism had a strong 
presence in comparative psychology. 
Rat Research Centers 
The final part of this chapter sought to determine the most prominent rat research 
facilities in the JCP. To accomplish this, I removed from the network any institution that studied 
a single organism less than thirty times. The logic behind this decision was that since the rat was 
such a dominant organism in this network, any institution with thirty or more instances with a 
single organism would likely be connected to the rat rather than any other species. I argue that if 
the most prolific rat research centers were behavioristic, then behaviorism was extremely 
influential in comparative psychology (via the JCP). Six institutions were revealed using this 
method (figure 18): the YLPB, Yale University, the University of Chicago, the University of  
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Network Analysis of the JCP 123 
California, the University of Minnesota, and Stanford University. Stanford and the YLPB were 
removed from the analysis due to their appearance in the previous chapters. Of the remaining 
four institutions, California (sr=74, d=6, wd=90)33 under Tolman, Yale (sr=37, d=11, wd=66) 
under Hull, and Minnesota (sr=34, d=3, wd=41) under Heron and Skinner were distinctly 
behavioristically oriented. Chicago (sr=34, d=13, wd= 51), run by the functionalist, Harvey Carr, 
was sympathetic to the behavioristic cause, but was less concerned about adhering to the strict 
framework that had developed.  
The University of California34 
Of the ninety publications that bore the affiliation of the University of California (UC) 
between the years 1920 and 1950, 74 were directly associated with the rat. The remaining 
seventeen publications were split amongst five other organisms: chicken, cat, monkey, pigeon, 
and human. In terms of historical significance, these numbers served as a confirmation of 
California?s prominence within this dominant intellectual trend. Indeed, the Berkeley campus 
was home to Tolman ? who I have established as a prominent neo-behaviorist ? and the many of 
his graduate students, namely, Robert Tryon, Calvin S. Hall, and David Krech, who continued on 
to their own successful careers in psychology. 
The story of the Berkeley was simple: Tolman and his students were, in large part, the 
reason Berkeley was so highly connected to the rat, and in turn, why it was also the most actively 
publishing institution. Although Tolman, himself, published only five studies on the rat in which 
he was first author, he also co-authored one article (as second author) with each of A.E. White 
(White & Tolman, 1923), F.C. Davis (Davis & Tolman, 1924), C.F. Sams (Sams & Tolman, 
33 (sr=number of studies published on the rat, d=degree, and wd=total weighted degree,) 
34 This included both campuses: the Berkeley campus, and the newly built Los Angeles campus. The fledging 
status of UCLA meant that only a handful of articles were published in the JCP from their department. 
Network Analysis of the JCP 124 
1925), and F.M. Geier (Geier & Tolman, 1943). He also served as second author with C.H. 
Honzik on two occasions (Honzik & Tolman, 1936; 1938). Including these two co-authored 
publications, Honzik contributed a total of five experimental articles on learning in the rat. Zing-
Yang Kuo, perhaps Tolman?s most recognized student, conducted eight studies, only one of 
which was while he was at Berkeley (Kuo, 1922). Tryon?s entire academic career was spent at 
the Berkeley, and thus, all ten of contributions to the JCP came under that affiliation. Further 
than this, Tolman served as supervisor to multiple dissertations in which he received no 
authorship credit.35 Predictably, these papers were on maze learning in rats. 
Other important figures published for brief spurts of their career under the UC affiliation 
in this time period. Isadore Krechevsky, later known as David Krech, came to Berkeley in 1932 
to study under Tolman, eventually taking his PhD in 1933. Although his work was mostly 
remembered for contradicting the common held belief that learning was trial and error based and 
he eventually moved closer to psychobiology, he always considered himself a Tolmanian (Krech, 
1974) and he and Tolman remained life-long friends (Ghiselli, Beach, Pickerall & Rosenzweig, 
1978). He contributed seven publications on the rat to the JCP, however, only one came while at 
UC; as shown in the previous chapter, his other six experiments were published under the 
affiliation of the University of Chicago. Calvin S. Hall, who was influenced in his undergrad by 
Guthrie, and one of the most visible psychologists between the years 1935 and 1975 (Lindzey, 
1987),36 took his PhD at UC under Tolman and Tryon in 1933. Hall published seven rat 
experiments as first author in the JCP in the period between 1920 and 1950. His first two (1934; 
1934) came while he was at the UC, the next three were affiliated with Oregon (1936; 1936; 
1937), and the final two while chair at Western Reserve (1941; 1942).Finally, Egerton L. 
35 This claim is made off of mentions in footnotes that the author is indebted to Prof. Edward Tolman. 
36 His most well-known research was his later work on psychoanalytic theory and in dreams. 
Network Analysis of the JCP 125 
Ballachey, a member of the Tolman laboratory, did what many before him had done: he took his 
PhD under Tolman, stayed for a brief time at the UC, and then left to explore different research 
areas. Ballachey had seven publications dedicated to animal learning ? an impressive 
accomplishment for a graduate student, even one in Tolman?s prolific laboratory. Only two of 
Ballachey?s papers were published in the JCP; both were focused on learning in rats, were 
affiliated with the UC, and were published in 1934. 
Tolman might not have been one of the most active JCP contributors, but his influence 
was felt heavily in the proliferation of his laboratory?s research (Krech, Ghiselli & Tuddenham, 
1974). In fact, researchers at the UC favored the JCP more than any other institution in this era, 
publishing the most articles in this time frame. Tolman?s influence was also seen in the adoption 
of rat research at Berkeley. With a degree of six, the UC was not a comparative laboratory in the 
way we have come to define the word: the rat accounted for 82% of the institution?s articles. In 
fact, prior to Tolman?s arrival in 1918, the UC, although modest in its output, did not study rats 
and was highly comparative: from 1913 to 1918, Berkeley researchers published six articles on 
six different species, none of which were on humans or rats. Tolman researched humans at 
Harvard, but quickly adopted the rat upon his move to California. And although Tolman?s theory 
was not as wide-spread as Hull?s, he ran the most prolific behavioristic department in the JCP.  
Yale University 
Similar to Berkeley, Yale was home to one of the most prominent neo-behaviorists of the 
era, Clark L. Hull. But unlike Berkeley, Hull was not as influential throughout the entire period 
the same way Tolman was. Yale, during the 1920s, was under the control of Yerkes, and 
although Hull took over the Institute of Human Relations (IHR) in 1929, his influence was not 
fully felt until the 1940s, the peak of his theoretical dominance. Hull, who was at Wisconsin 
Network Analysis of the JCP 126 
from 1913 to 1929, conducted most his research while there on hypnosis and aptitude testing. 
Even though he became interested in behavior in 1930 (Hull, 1952), he did not begin his full-
fledged behavior program ? which came to be described as ?the Yale brand of behavioral theory? 
(Sears, 1982, p. 1280) ? until the mid to late 1930s. 
Yale University?s degree of 11 indicated that the institution was the second most 
comparative behind Chicago. However, as was seen in chapter one, the strength of Yale?s 
comparative program came from Yerkes and his Laboratories of Comparative Psychobiology. 
Moreover, Yerkes, who had studied the rat while at Harvard, was not particularly high on the 
species, with only two of thirteen articles published on the rat at Yale under his headship. Upon 
the establishment of the Yale Laboratories of Primate Biology, Yerkes and his comparative 
program stopped affiliating as ?Yale University,? eventually leading to Yerkes?s desire to sever 
all ties with the parent institution (Biehn, 2008). Thus began Yale?s ascent into, arguably, the 
premier ?hub? of neo-behavioristic research.  
The IHR37 was established nearly the same time as the Orange Park facility and was 
funded with the same Rockefeller grant. Biehn (2008) argued that both projects were integral to 
the establishment of the other, perhaps even an ?all-or-nothing? situation. Certainly, the promise 
to the Rockefeller Foundation was that the YLPB and the IHR38 ?were to be cooperative 
enterprises, in which scientists moved outside of their disciplinary boundaries to address human 
behavior as a psychological, psychiatric, social and physiological issue? (Biehn, 2008, p. 33). A 
friend, student, and supporter of Hull?s, Kenneth W. Spence, was doing exactly that: he 
published work on learning in rats under the affiliation of Yale?s IHR and work on primates 
under the affiliation of the YLPB. His research on primates, however, was intended as a response 
37 For the Institute of Human Relations, see Morawski, 1986. 
38 For a more complete description of the founding of both institutions, refer to Biehn, 2008, and Morawski, 
1986. 
Network Analysis of the JCP 127 
to the implication that reason reigned supreme in apes (K?hler, 1925; Yerkes, 1943) and 
monkeys (Harlow, 1949). Although these primates clearly displayed reasoning, Spence (1942) a 
fervent Hull supporter, argued that the chimpanzee?s behavior only adhered to the stimulus-
response learning processes, and did not display any reason or intellect (Spence, 1942; 
Rumbaugh, 1997). Of all the researchers at the YLPB conducting similar research, Spence was 
the only one who denied that the apes displayed reason, sticking with his stimulus-response 
relationship claim (Rumbaugh, 1997).  
In any case, the arrival of Hull and the establishment of the IHR was seen almost 
immediately within the network: of the 24 articles published in the JCP from 1930 to 1939, 
fifteen were on the rat. In terms of percentages, more than 60% of the total articles dealt with rat 
behavior, four times the 15% in the previous decade. Although this occurrence might be 
attributed to Hull?s new influence on the direction of the department?s research, it was only 
partly the case. Only seven of the fifteen articles were in some way attributed to Hull or the IHR; 
three of these articles were published by Hull. The remaining eight were affiliated with the 
Laboratories of Comparative Psychobiology (LCP), and did not feature any stimulus-response 
studies. However, the majority of the early IHR affiliated articles came after 1935, indicating the 
beginning stages of Hull?s massive discipline-wide influence. The next decade (1940 to 1950) 
saw Hull?s biggest influence at Yale. This decade consisted of 25 studies with eighteen on the rat 
(72%). Although there were a few articles that were affiliated with the LCP or just ?Yale 
University,? the vast majority of the papers were coming from the IHR. Hull himself only 
contributed one first authored and one second author article to the JCP in this decade. Like 
Tolman, Hull?s influence came in the number of dissertations published on the rat under his 
purview. Moreover, by the mid 1930s, the main focal points of the IHR and Yale conformed to 
Network Analysis of the JCP 128 
Hull?s theories and work. And although this only lasted until his death in 1952, his approach was 
carried on by his student, Spence, who had since moved to the State University of Iowa 
(Hovland, 1952). Spence himself published six first-author and two second-author articles in the 
JCP with only one of his first-authored articles coming under Iowa?s affiliation. 
Although sharing similarities to California, Yale fit into its own category. After James 
Rowland Angell revived the psychology department from the early dark days of the past, the 
institute early on was beacon for comparative psychobiology before transforming into a ?hub? 
for neo-behaviorism.  
University of Minnesota 
The early history of the Minnesota psychology department ? including Yerkes?s tenure as 
chair and Lashley?s years running the comparative laboratory ? was discussed in the chapter one. 
For this chapter, the story at Minnesota begins with the hiring of Yerkes?s replacement, Richard 
M. Elliot. Elliot was chair for thirty-two years, and from the start believed that Minnesota stood 
the best chance as a behavioristic institution. This resulted in his hiring of the famous 
behaviorist, B.F. Skinner, in 1936, who was highly productive while at Minnesota (Department 
History, 2013). The psychology departments at Minnesota and Chicago were interconnected in 
this period by two threads: first, Lashley had left Minnesota to take a position at Chicago; and 
second, William Thomas Heron took his PhD from Chicago under the supervision of Carr in 
1924. After a brief stay at the University of Kansas,39 Heron was offered a full professorship at 
Minnesota, a position he held from 1925 till his death. Although the 1920s was stamped with 
Lashley?s influence, nearly a decade later, Heron had taken control of the department, churning 
out new doctorates(?) and decidedly changing rat research at Minnesota from Lashley?s 
39 Heron graduated with an MA at Kansas working under the known comparative psychologist Walter S. 
Hunter. He returned in 1924 to take up a position as assistant professor, presumably working once again with 
Hunter. 
Network Analysis of the JCP 129 
psychobiological perspective  to a more traditional ?behavioristic? approach. Interestingly 
enough, Heron had been at Minnesota for a decade before he began publishing in the JCP in 
1935, which closely coincided with the arrival of B.F. Skinner in 1936. 
Minnesota?s degree of three made it the least comparative department of the four. Only 
the rat, human, and chicken were being studied in the 31 year period with the rat accounting for 
83% of the publications. This new wave of rat research coming out of the Minnesota laboratory 
closely resembled the prevailing behavioristic approaches of the day. After the last of Lashley?s 
students had cleared through (some being recruited by John E. Anderson40), a changing of the 
guard began. With Heron and Skinner working together at Minnesota, Elliot?s vision of a 
behavioristic department was complete. As was mentioned earlier, Heron was at Minnesota a 
decade before he first published in the JCP. This was no doubt due to his early career preference 
of using more general journals as an outlet to disseminate his work (Psychology Bulletin, and 
Pedagogical Seminary). Also, many of his early publications were descriptions of various 
apparatus, and thus, did not qualify for this analysis. Nonetheless, his first students started 
publishing their dissertations in 1933 (E.A. Rundquist, 1933). Heron?s (d=1, wd=6) first 
experimental publication in the JCP came in 1935, and he continued to publish throughout the 
40Anderson?s arrival at Minnesota in 1926 coincided with two things, the founding of the Institute for Child 
Development in 1925, and the appointment of Florence Laura Goodenough as assistant professor at Minnesota, in 
1925. Both child development psychologists were most likely drawn to Minnesota based on the newly formed Child 
Institute. Indeed, Anderson was called to Minnesota to organize a research program in child development (Templin, 
1968). Along with the presence of Goodenough, the Institute had a fairly distinct female connection: Anderson 
graduated with a BA at the University of Wyoming in 1914, and there collaborated with the Wyoming female 
psychologist, June Downey, to publish a paper in 1915. He finished his education at Harvard, where he took his MA 
in 1915, and his PhD in 1917, both under M?nsterberg. After serving in the war for two years, he was appointed 
instructor at Yale in 1919, teaching until his move to Minnesota in 1926 (Templin, 1968). The three female students, 
Shirley, Hubbard, and McCarthy, who were previously studying learning in rats with Lashley, all changed their 
research interests towards child development after Lashley left. Anderson (1932) only published once in the JCP, an 
article on the effects of nutritive conditions on learning in the rat. Perhaps he believed the JCP was more of an 
appropriate outlet to publish his rat work, as he preferred other periodicals for his and his students? work on child 
development (namely the Psychological Bulletin, and Child Development). Indeed, Goodenough, Anderson, and 
their students stopped publishing in the JCP after 1932. Nonetheless, his influence was strong enough to recruit 
Lashley?s former students over to child development research. 
Network Analysis of the JCP 130 
period of 1935 to 1950 for a total of six first-author and two second-author publications. 
Although Skinner did not publish experimental research in the JCP during this period, his arrival 
in 1936 sparked an active collaboration between Heron and Skinner up until 1940, with the 
majority of their co-authored articles published in The Psychological Record.  
As a product of Harvey Carr, who ran one of the most productive laboratories at Chicago, 
it is unsurprising that Heron was producing a new graduate yearly from 1937 to 1942. Similarly 
to Tolman?s and Hull?s (and later, Carr?s) department, Heron?s department was characterized by 
many single (?one and done?) dissertation publications by different researchers on the rat?s 
learning behavior. In this period, Heron?s most prolific student was Kenneth MacCorquodale 
(d=1, wd=3), who published three first-author publications and two as second-author. All of 
MacCorquodale?s articles were on the rat, and all were distinctly pro-Hullian (MacCorquodale & 
Meehl, 1948; Meehl & MacCorquodale, 1949), insofar as they attacked Maier?s research on 
?reasoning,? and Tolman?s theories on (no) reinforcement and latent learning. Reinforcement, of 
course, was a main tenet of Hull?s and Skinner?s theoretical frameworks. The work by 
MacCorquodale and Meehl that attempted to disprove other theories while supporting their own 
characterized the direction research took at Minnesota from 1935 on. 
The story of the Minnesota psychology department is an appropriate case study on the 
impact of behaviorism on comparative psychology. The department had distinct comparative 
roots; the department?s first chair was the animal psychobiologist Robert Yerkes, and his first 
hire was the comparative psychobiologist Karl Lashley.41 Moreover, Heron was a student of the 
functionalist and comparative psychologist, Harvey Carr. Yet, the new chair, Elliot, understood 
the situation at Minnesota better than Yerkes ever did. He realized that to remain relevant in the 
current literature of the day, they could ill afford a purely comparative (and perhaps outdated) 
41 Throughout his career, Lashley conducted studies on at least five different species. 
Network Analysis of the JCP 131 
department and needed to find their place within the behavioristic framework. The 1920s was a 
time when Watsonsonian behaviorism was abandoned and other forms of ?radical? behaviorism 
were being exposed. Indeed, Lashley conducted some of the experiments that destroyed these 
stimulus-response theories. This bred a time ripe with competing theories on the ?lawfulness? of 
behavior, and no single theory was the ?standard.?42 With the rise of Tolman, Guthrie, Hull, and 
other theory builders, behavioristic theory was beginning to reunify. Elliot knew that 
psychological theory was in a transition phase, so he, and the department under his purview, 
embraced this change by bringing over Skinner from Harvard, in 1936, to join the incumbent, 
Heron. This move indicated Elliot?s success in turning Minnesota from a shrinking comparative 
department, to a growing behavioristic one run by Heron and Skinner. 
University of Chicago 
The second chapter established Lashley?s lasting influence on the research coming out of 
the Chicago department. Furthermore, Chicago?s appearance as one of the most prolific rat 
research centers also owed much to Lashley?s tenure there from 1929 to 1935. However, 
Chicago?s reputation as one of the most productive and comparative departments in this era was 
due mostly to functionalist and comparative psychologist Harvey A. Carr, who took control of 
the department in 1922 and remained in charge until 1938. Like Lashley, Carr shared Watson as 
a mentor, albeit it at Chicago rather than Johns Hopkins. Also like Lashley, Carr had an affinity 
to the rat as a research subject.  
Prior to coming to Chicago, Carr received his MA from the University of Colorado under 
the purview of Arthur Allin, in 1902. It was Allin who introduced Carr to psychology. Often 
42 Many considered Hull?s theory as the ?standard,? but this did not take hold until the 1940s.  (Benjamin, 
2007).  
Network Analysis of the JCP 132 
considered the last functionalist, Carr43 took his PhD under the likes of known functionalists44 
John Dewey and James Rowland Angell, as well as John Watson. It seemed, however, that Carr 
was most heavily influenced by Watson. Indeed, in 1908, when Watson moved to Johns 
Hopkins, he handed the reins of the animal psychology program he developed during his time at 
Chicago over to Carr (Pillsbury, 1955). After taking control of Watson?s laboratory, the newly 
graduated Carr set out to work on the white rat. His main area of research focused on the 
different senses the white rat relied upon when navigating a maze.45 In his APA presidential 
address in 1927 entitled ?Interpretation of the Animal Mind,? he asserted his stance within the 
discipline: ?I am somewhat of a behaviorist in the field of animal psychology, although I do not 
class myself as such so far as human psychology is concerned? (Carr, 1927, p. 104). This 
43 Harvey Carr joined other members, Dewey, Angell, and George Herbert Mead, to make up the Chicago 
school of functionalism. Another group of functionalists were headed by James McKeen Cattell at Columbia, and 
also included E.L. Thorndike, and Robert S. Woodworth (Green, 2009, Whitely, 1976). 
44Near the close of the nineteenth century, the reaction time tests that Wundt relied on were beginning to fall
apart, threatening to undermine his entire physiological psychology program. Wundt predicated his theory on their 
being a single ?normal? mind, and his inconsistent reaction time data indicated individual differences that, of course, 
disproved Leipzig?s position (Knight, 1994). Wundt?s assistant, Ludwig Lange (1886) restored order momentarily, 
until James McKeen Cattell, Wundt?s American assistant revealed that some individuals have a natural propensity to 
respond quicker. A loyal proponent of Wundt, Edward B. Titchener, defended Lange?s work (which refuted the 
work of Cattell) on the bases that certain individuals were not experienced enough at the task, in which case they 
lacked the ?mental disposition? to respond correctly. This led to a verbal debate between Titchener and James Mark 
Baldwin, who in his own studies, found none of the consistency Titchener had claimed (Green, 2009).  
At the same time, James Rowland Angell and Addison W. Moore, at the University of Chicago, conducted the 
most wide-ranging set of reaction time tests yet, and argued for a ?dynamo-genetic? theoretical framework. They 
purported that a response to a stimulus was not merely a reflexive act explained through physiology, but included 
the attention the observer placed on the sensory form elicited by the stimulus. For them, the time it took for an 
individual to respond was directly related to how fast an observer shifted their attention from one sensory form to 
another. A common example is the difference in time it takes one to shift their attention from the ear to the hand 
when responding to an auditory stimuli; the ear, of course, being the more habitual relationship (Angell & Moore, 
1896, p. 252; Green, 2009). Not long after, Chicago professor John Dewey, Angell and Moore?s mentor, published 
functionalism?s founding document, ?The Reflex Arc Concept in Psychology? (Dewey, 1896), that outlined the 
theoretical foundation developed by his students.  
The story of Watson?s tenure at Chicago is best described by Kerry Buckley (1989). A student of Angell?s, 
Watson took his PhD by the young age of 25, in 1903. Learning under Dewey and Angell, the new doctorate Watson 
turned down many offers and took an instructorship position at Chicago where he continued to work with the latter 
(Benjamin, 2007). Functionalism, with its concern on learning as an adaptive means to a changing environment 
provided Watson a unique position to study with animal subjects.44 Animals created the ideal subjects since they 
could be bred and allowed them to be in ?controlled? conditions. They also turned out to be great learners 
(Benjamin, 2007). Watson established an animal psychology program at Chicago and this animal research came to 
dominant functionalism, behaviorism, and comparative psychology. 
45 Carr used a maze he devised himself that was widely used (Pillsbury, 1955).  
Network Analysis of the JCP 133 
position was revealed in Carr?s discussion of consciousness in animals. He believed 
consciousness in animals can only be decided if animals and men are shown to respond similarly, 
a claim he was uncomfortable making. In fact, Carr expressed caution in the anthropomorphizing 
of animals in many of his papers; he acknowledged this hostility to anthropomorphic 
interpretation as a precipitate of the intellectual environment he was reared and nurtured in at 
Chicago (Carr, 1927). Even though he personally approved of behaviorism, he believed 
experimental evidence could be attributed only to the animal that was under study, and could not 
be a surrogate to the understanding of the human mind. With Carr?s doctrine intact, and his 
emphasis on animal research, the Chicago laboratory rarely researched human subjects. Indeed, 
Chicago published only four articles on the human in the period of 1920 to 1950, which was 
considerably less than the 34 on the rat.  
Carr?s career research centered around comparative psychology, space perception, and 
learning. As such, these three topics formed the basis of the experimental work stemming from 
the Chicago psychology department, with a distinct focus on non-human organisms. From the 
years between 1920 and 1950, Carr (d=1, wd=1) published only one article as single author 
(1926), and co-authored one with Siegfried Maurer (1935) in the JCP. In this scenario, the 
network was only able to document Carr?s contribution to the journal, and thus, the visualization 
was unable to portray his individual influence in comparative psychology. This is unsurprising 
considering Carr?s importance in the discipline has mostly been linked to the influence he had 
upon his students while at Chicago, and later when they were directing their own laboratories. 
Indeed, he was an institutional or ?organizational? man rather than a laboratory scientist 
(Pillsbury, 1955). Of the 131 degrees that were awarded while the department was under the 
purview of Carr, the majority benefitted in some capacity from his advisorship (Koch, 1955). 
Network Analysis of the JCP 134 
Moreover, he was directly responsible for 53 doctorate degrees; 18 in animal work, 29 in 
learning, and 6 in space perception (Pillsbury, 1955).  
Similar to the Berkeley, Yale, and Minnesota departments, Chicago?s contribution to the 
JCP was mostly through many single dissertation publications by different researchers. Only two 
researchers, Loh Seng Tsai and Siegfried Maurer, published more than one article in this time 
period under the affiliation of Chicago (with the exception of Lashley), and both were in some 
way tied to Carr. Tsai (d=1, wd=2) took his PhD at Chicago in 1928, and joined the faculty ranks 
in 1929 (Lindley, 1993). He published two articles on the rat in the JCP as a single author (1930; 
1931), and one as a co-author with Siegfried Maurer. Maurer (d=1, wd=6) was a graduate of 
Rush Medical School, and a physician that practiced in Chicago from 1924 to 1952. He 
published six articles on the rat, but was especially prolific in the year 1935 when he published 
five articles as single author, including one in which Carr was co-author. Both Tsai and Maurer?s 
research focused on maze learning in rats.46 
Under the purview of the functionalist and comparative psychologist Carr, rat research at 
Chicago never strictly adhered to the stimulus-response framework that classified many 
psychology laboratories at the time. However, it appeared that as a functionalist, which has been 
closely linked to behaviorism (Green, 2009), Carr and his department were sympathetic to 
behavioristic theory. Interestingly, after Carr?s retirement in 1938, only two articles were 
published on the rat at Chicago during the period of 1939 to 1950, and both of these articles were 
published in 1939 by K.W. Bash.47 Apparently, Carr?s preference for the rat was the driving 
force for the rat research generated at Chicago, or at least the rat research published in the JCP. 
46 Both researchers began publishing in the JCP by 1930, one year after Lashley had accepted a professorship to 
Chicago. 
47 Both of these articles were received for publication in November of 1938, providing credence to the claim 
that Carr was the driving force behind rat research at Chicago (Bash, 1939; Bash, 1939). 
Network Analysis of the JCP 135 
However, unlike Yale which was comparative prior to becoming a rat research center, Chicago, 
under the self-proclaimed comparative psychologist Carr (Pillsbury, 1955), had remained 
comparative throughout. In fact, with a degree of 13, Chicago studied the most diverse array of 
subject species of any institution publishing in the JCP from 1920 to 1950. Among these thirteen 
species were the dog, cat, chicken, mice, salamander, human, frog, and monkey.  
The histories of all four of these ?hubs? for rat research pointed to three things: first, the 
proliferation of the institution?s research was attributed to the influence of one or two prominent 
laboratory ?heads?; second, the majority of the rat research came in the form of single 
dissertation publications, and thus, resembled a ?factory-like? approach to churning out new 
doctorates; and third, a low degree indicated that the institution was more likely to have adopted 
a behavioristic approach. Yale under the guidance of Hull,48 California under Tolman, and 
Minnesota under Heron and Skinner all had low degrees and had fully invested in the rat as a 
subject to study behavior via learning (or performance in Tolman?s case). Although not opposed 
to behavioristic theory, Chicago, with a degree of thirteen, was the only one of the four 
institutions not behavioristically oriented, and thus, illustrated that the least comparative 
departments were most likely to have been behavioristic institutions. 
Taken collectively, this chapter has provided credence to Beach?s claim that the influence 
of behaviorism in the JCP was strong and pervasive, and went far beyond the individual 
contributions of the neo-behavioristic giants. The fact that most of the rat research in the JCP 
was emanating out of behavioristic institutions further emphasized the earlier argument that the 
rise of the rat in the 1930s was an artifact of neo-behaviorism and the theories of the neo-
behavioristic giants, Tolman, Hull, and Skinner. Moreover, of the five authors depicted by the 
network to be most prolifically studying the rat (Muenzinger, Bunch, Siegel, Tryon, Young), 
48 All of Yale?s comparative work came under Yerkes. 
Network Analysis of the JCP 136 
only Young was characterized as something other than a neo-behaviorist. Muenzinger, Bunch, 
and Siegel, and to a lesser extent, Tryon, were all considered ?dust bowl empiricists? and these 
individuals were only a few examples of the broader acceptance of behavioristic theories by 
experimental psychologists. Although Beach?s claim that behaviorism had essentially replaced 
comparative psychology was misinformed, he was correct in drawing attention to its impact on 
comparative psychology.  
Network Analysis of the JCP 137 
Conclusion 
There has been no consensus by historians on the successes and failures of comparative 
psychology, or even if there was a fully active comparative discipline after the 1920s. One 
common thread amongst all histories on comparative psychology was the widespread adoption of 
the Norway (white) rat, and the maze learning studies they featured in. However, Donald 
Dewsbury (1984) has shown in his book, Comparative Psychology in the Twentieth Century, that 
comparative psychology cannot be reduced to only the organisms studied, but its history needed 
to include the full breadth of the discipline. Achieving this breadth, Dewsbury contended, could 
not be done via the frequency counts of organisms studied, employed first by Theodore Christian 
Schneirla, and expanded upon by Frank Ambrose Beach and many other historians. Furthermore, 
while Dewsbury acknowledged that rat research was predominant in comparative psychology, he 
argued that focusing on this aspect alone masked the importance of individual comparative 
research papers (on both rats and non-rats) and textbooks contributed to the discipline. 
Moreover, Dewsbury argued that although the ranks of comparative psychologists have never 
been many, the few were prominent and highly influential within the broader discipline of 
psychology. It was these few, multi-generational prominent psychologists that Dewsbury 
believed established and continued the ?rich history of a broad-based, evolution-oriented science 
of behavior? (Dewsbury, 1984, p. 2). He chronicled the history of comparative psychology in 
decades, claiming that the 1910s and 1920s were a time of development, transition, and 
maintenance in comparative psychology, accomplished from the research of a few ?first 
generation? comparative psychologists. Dewsbury then argued that the 1930s saw comparative 
psychology prosper (a claim that was not supported by many historians), mostly due to the 
Network Analysis of the JCP 138 
arrival of the ?new generation? of comparative psychologists. He further purported that this new 
generation helped sustain the vigor developed in the 1930s into the 1940s.  
Beach understood this rat phenomenon less optimistically than Dewsbury, seeing it as 
effectively replacing comparative psychology with behaviorism. Indeed, aside from the pigeon, 
which was popularized by Skinner and his ?radical? behaviorism in the 1960s, the rat has 
historically been recognized as the model organism in behaviorism. Moreover, the rat?s rise to 
prominence as a subject species began in the 1920s but reached its peak use in the 1930s, 
coinciding with the establishment of numerous competing behavioristic theoretical frameworks. 
Thus, it was a short leap for Beach to connect the mounting rat studies in comparative 
psychology to the advent of behaviorism. However, as was discovered in this thesis, the rat was 
not an exclusively behavioristic organism, but the versatility of the rodent made it a staple in 
developmental, neurological, and physiological studies as well. Additionally, the animal was 
used equally in the research programs of behaviorists and non-behaviorists (what I have termed 
as psychobiologist). Beach was not unaware of the diverse use of the rat, and did not claim that 
all rat research was behavioristically oriented. To guard against this generalizing statement, he 
attempted to decipher the different topics of research and found that the rat was not only used in 
staggering numbers, but learning studies reigned supreme in comparative psychology, and these 
learning studies typically featured rats working through variously shaped mazes. This was the 
bases in which Beach claimed that behaviorism had essentially replaced comparative 
psychology. 
There were obvious methodological differences in Beach?s and Dewsbury?s studies, and 
this led to the use of different data. Beach employed a frequency analysis of the organisms used 
in the Journal of Comparative Psychology, and coded seven distinct categories of research. 
Network Analysis of the JCP  139 
 
 
 
Beach?s data included only odd numbered volumes of the JCP from 1911 to 1950, predicating 
his entire argument on this subset. Dewsbury employed a fuller history of comparative 
psychology, including in his data not just publications in the JCP, but also the many influential 
textbooks that surfaced, the articles in other, more general psychology periodicals, conferences 
and other important events, as well as prominent institutions, individuals, organisms, and 
groups/councils. It was clear upon investigating the literature that the claims made by each 
author were legitimate, and it was the reconciling of the simultaneous existence of both claims 
that animated this study.  
In my analysis, I attempted to bridge the ?data? gap between these two important 
critiques on comparative psychology in order to view each claim via the same lens. Although I 
similarly only used data from the JCP, I employed a fuller analysis of the journal, including all 
of the metadata from 1911 to 1950. I also expanded the data to include not just the model 
organisms and the studies they featured in, but also prominent researchers and institutions. The 
inclusion of the most prominent researchers and institutions allowed for the extrapolation of 
important historical information not available from the metadata. This approach allowed me to 
repair methodological shortcomings in both studies. Whereas Beach only used part of the data, 
and focused his entire study on numbers and proportions alone, I used all of the data in the same 
time period whilst simultaneously employing traditional historical methods. Dewsbury, although 
expansive and thorough in the breadth of his data, focused the majority of his book on the most 
important, cause for celebration, moments in the discipline?s history. This approach failed to 
capture the broader disciplinary trends that were present when viewing frequency counts and 
proportions. Thus, I employed a network analysis ? a common tool in digital history ? for this 
study in an attempt to visualize this data in a way that included both the frequency counts and the 
Network Analysis of the JCP  140 
 
 
 
historical narrative of comparative psychology. This allowed me to conceptualize the broader 
organism trends and discuss the specific historical actors responsible for maintaining 
comparative psychology. I organized the data into two different types of networks: one depicting 
the relationship between organism and scientist; and the other depicting the relationship between 
the organism and the institution conducting the research. 
It is ironic that the most advantageous feature of this study (including all of the data in a 
particular time period) was perhaps the most limiting. The sheer number of data points made not 
only the networks very large and dense, but the spreadsheet incomprehensible without the ?find? 
function. With such dense networks, there is no shortage of storylines to follow, and one could 
find themselves writing a superficial overview of the discipline. To refrain from falling into such 
traps, I utilized the network visualization in conjunction with an extensive literature review. The 
information gathered from the network could be broken into two components: measures of 
degree centrality, and the structure of the network. Degree centrality is a quantitative measure 
that is used at the individual node level that consists of degree and weighted degree. Degree 
measures the number of distinct connections a node had in the network, and indicated how many 
organisms a particular scientist or institution studied, and conversely, how many scientists and 
institutions studied a particular organism. Weighted degree is the total number of connections a 
node had, and designated the most active scientists and institutions, or the most actively studied 
organisms. The structure of the network was analyzed as the total shape of the overall network, 
which was useful in determining different communities of scientists/institutions and organisms, 
and by the individual positioning of nodes within the network. Only the position of nodes that 
represented scientists were analyzed in this thesis and their individual positioning was highly 
dependent on their measures of degree centrality. Highly comparative scientists (high degree) 
Network Analysis of the JCP  141 
 
 
 
were most likely to be surrounded within the network, as these individuals connected multiple 
organism communities. Actively publishing individuals (high weighted degree) were likely to 
have been represented by bigger nodes and most closely positioned to their model organism.  
Furthermore, I utilized the network visualizations in two different ways in my study, as a 
guiding tool and as a way to reify existing historical facts. This is an important distinction which 
speaks to the versatility of the technique. To unpack this more, I used the network to determine 
which scientists and which institutions were most closely connected to the rat, and thus, used the 
network to ?guide? me to the correct answer. I also used the network to confirm established 
historical events, which took the form of tracking certain scientists (Yerkes, Lashley, Stone, etc.) 
and the different institutions they were affiliated with. In this case, the network did not provide 
original information, but served as a visual confirmation of the pre-established historical facts. 
These are just two of the many ways networks can be interpreted. 
To supplement these quantitative and structural measures innate to network analysis, I 
employed knowledge gained from other historical accounts on comparative psychology. Since 
there was such a rich historiography on behaviorism, it was not difficult to code certain ?check 
points? of the movement ? the rat and behaviorist giants like Tolman, Hull, and Skinner ? that 
would help guide which parts of the network to focus on and how best to assess Beach?s claim. It 
was trickier in determining which parts of the network to focus on to assess Dewsbury?s claim, 
since there been little consensus on the term ?comparative psychologist? or even ?psychologist,? 
for that matter. Thus, I used the term ?psychobiology,? as defined by Robert Yerkes and Knight 
Dunlap, the two founders of the journal under consideration, to represent the opposite of a 
behaviorist, or a non-behaviorist. I also included the term ?comparative? to the tag of 
psychobiologist to imply an individual?s documented importance in the comparative discipline. 
Network Analysis of the JCP  142 
 
 
 
The ?check points? that designated a ?comparative psychobiologist? was the inclusion of some 
aspect of biological importance in the study of behavior, as well as a non-adherence to a 
behaviorist approach. As was found in the thesis, a comparative approach (high degree) was not 
always the best indicator (e.g., Maier and Beach).  
Combining the quantitative measures of the network with established historical precedent 
led me to the finding that both Beach?s and Dewsbury?s claims on the status were centrally 
correct, but both slightly flawed in their belief that the two claims were mutually exclusive. For 
Beach?s claim to have been fully correct, comparative psychology would indeed have 
disappeared and been completely replaced by behaviorism (rat learning). This, however, was not 
the case as a handful of prominent comparative psychobiologists maintained a tradition of 
comparative research throughout the time period. And however much this reifies Dewsbury?s 
claim, his history fails to fully examine the large scale behavioristic trends that seriously 
impacted the comparative discipline. Thus, although Beach was extreme in his pronouncement 
on the status of comparative psychology, he was signaling attention to what was indeed a 
growing phenomenon within the discipline. Interestingly, lost in these competing arguments 
were the similarities between the two groups of scientists: both studied the rat; both were 
committed to separating themselves from the mentalistic aura of psychology?s past; and both 
focused on objective laboratory experiments measuring overt behaviors (although 
psychobiologists did conduct field studies).  
Of course, too many data points was not the only limitation in this study. One other one 
was that the nodes represented three different actors (organism, scientist, institution), making it 
illogical to compare the degree centrality of dissimilar nodes. For instance, one cannot compare 
the degree of Harvard University (no matter how high it was) with the degree of the rat because 
Network Analysis of the JCP  143 
 
 
 
their nodes are representative of different objects. This is an issue because the network views 
these nodes as similar, even though they are not. Dealing with this limitation was fairly 
straightforward; one just has to avoid drawing conclusions about dissimilar nodes. However, the 
benefits of using a network analysis for a study like this far outweighs the potential issues. Why 
the network was tailored to the research in this thesis was because it allowed an opportunity to 
bridge the two claims by showing a more complex and complicated picture than frequency 
counts alone, while still keeping the important functions frequency counts serve. Additionally, 
with the inclusion of extra data points (authors, and institutions), and the particular connections 
they made, the networks provided a visual snapshot of the breadth and complexity that 
Dewsbury argued was the nuance necessary to properly assess the history of comparative 
psychology. 
Another determination that needs to be addressed is whether or not tracking multispecies 
networks of researchers and their chosen experimental populations was a reliable technique for 
identifying 1) their theoretical orientations; 2) their institutional affiliations; and 3) some other 
group or communal identity. Using the JCP as an example, it appeared that the answers to these 
questions were varied. I was unable to unequivocally identify an individual?s theoretical 
orientation using the network because the rat was such a versatile organism that both behaviorists 
and psychobiologists studied the animal. However, the organisms a particular scientist studied 
did provide some predictive value in determining a theoretical orientation. For example, if an 
individual was studying multiple organisms, it would be safe to predict that that scientist, 
comparative in their research approach, was most likely to have been a psychobiologist over a 
behaviorist. Even with this predictive value, one still needed to ?double check? a scientist?s 
theoretical disposition to be certain.  
Network Analysis of the JCP  144 
 
 
 
Since the network was meant to portray the dyadic relationships between scientists and 
organisms and institutions and organisms, this was not the best technique for identifying an 
individual?s institutional affiliation. The best way to determine this would still be mining it 
directly from the published article. Again, however, there was some predictive value in 
connecting the scientist?s organism of choice with the institution?s organism of choice. For 
example, as was exemplified in the thesis, the Yale Laboratories of Primate Biology, the 
University of Wisconsin, and Indiana University were the foremost institutions researching the 
chimpanzee, the rhesus monkey, and the dog, respectively. Thus, if a scientist had a particularly 
close connection to one of these organisms, it would be safe to predict their institutional 
affiliation. Similar to an individual?s theoretical orientation, the only way to confirm a scientist?s 
institutional affiliation was through consulting external resources (i.e., the article themselves). 
The network was a reliable technique in determining an individual?s identity in a group or 
community. In fact, I would argue that one of the greatest advantages of the network is how it 
organizes individuals into communities based on their preferred model organisms. Thus, all 
individuals studying the rat were positioned close to the rat node in the network, and effectively 
became its own cluster or community. This was the same for other organisms as well; all 
monkey researchers were positioned close to the monkey, forming its own cluster. Of course, the 
size of a particular cluster or community depended upon the number of scientists connected to 
that organism. Understanding that the network organized the data in such a fashion, one is able to 
make an unequivocal claim about a particular researcher?s communal affiliation simply by 
looking at their position within the network. However, this ?communal? affiliation did pose 
some problems when two individuals with contrasting theoretical orientations were organized in 
the same community. To illustrate this point, Frank Beach?s close connection to the rat meant 
Network Analysis of the JCP  145 
 
 
 
that he was integral to the overall rat community. If we take this close affiliation with the rat 
community at face value, we run the risk of misattributing Beach as a neo-behaviorist, when he 
was, in fact, a psychobiologist. This tells us two things. The first and most obvious is that there 
are some innate flaws with the technique insofar as its communal affiliation is dependent on 
species studied alone (this could also be an artifact of my coding decisions). The second, and 
more telling, is that these two groups (psychobiologists and neo-behaviorists) were not as 
different as once presumed. Both groups conducted behavioral studies on the same organism(s) 
(mostly the rat), both could be considered experimental psychologists, and finally, both 
published their research in the JCP. 
With the findings in this thesis spelled out above, one could extrapolate that the 
simultaneous existence of competing behavioral research programs created an ambiguity within 
the comparative discipline, and was perhaps the reason why there is no consensus on the 
discipline?s history and how the term ?comparative psychologist? should be used. However, the 
importance of this thesis went beyond the historical finding that the two arguments were not 
mutually exclusive and its significance in reassessing the status of comparative psychology. This 
thesis attempted to employ a novel approach to the assessment and writing of history, and thus, 
had important methodological implications. I have shown that the networks provided a platform 
to not only view and incorporate all the data into an analysis, but it allowed the historian to meld 
quantitative measures with the actual historical facts or, in the case of Beach and Dewsbury, the 
discrete frequencies with the complex back-story. Moreover, network analysis was a reliable 
technique in determining particular group or community affiliations. And although there are 
many shortcomings innate in these techniques, they are easily managed if the network is used as 
a supplemental tool, and not as an end in and of itself.  
Network Analysis of the JCP  146 
 
 
 
Bibliography 
[Cover]. (1911). Journal of Animal Behavior, 1, C1-C1. 
[Cover]. (1947). Journal of Comparative and Physiological Psychology, 40 (1), C1-C1. 
About the Institute. (2013). Retrieved August 16, 2013, from Institute of Child Development: 
http://www.cehd.umn.edu/icd/about/ 
Adkins-Regan, E. (1990). Is the Snark still a Boojum? The Comparative Approach to 
Reproductive Behavior. Neuroscience & Biobehavioral Reviews, 14, 243-252. 
Amsel, A. (1989). Behaviorism, Neobehaviorism, and Cognitivism in Learning Theory: 
Historical and Contemporary Perspectives. Hillsdale: Erlbaum. 
Amsel, A., & Rashotte, M. E. (1984). Mechanisms of adaptive behavior. New York, NY: 
Columbia University Press. 
Angell, J. R., & Moore, A. W. (1896). Studies from the psychological laboratory of the 
University of Chicago: 1. Reaction-time: A study in attention and habit. Psychological 
Review, 3 (3), 245-258. 
Beach, F. A. (1950). The Snark was a Boojum. American Psychologist, 5 (4), 115-124. 
Benjafield, J. G. (2005). A History of Psychology. Oxford, England: Oxford University Press. 
Benjamin Jr., L. T. (2007). A Brief History of Modern Psychology. Malden, MA: Blackwell 
Publishing Ltd. 
Benjamin, J. L., & Bruce, D. (1982). From Bottle-Fed Chimp To Bottlenose Dolphin: A 
Contemporary Apprasial of Winthrop Kellogg. The Psychological Record, 32, 461-482. 
Biehn, K. J. (2008). Psychobiology, sex research and chimpanzees: philanthropic foundation 
support for the behavioral sciences at Yale University, 1923?41. History of the Human 
Sciences, 21 (2), 21-43. 
Billings, E. G. (1939). Part one: Psychobiology. In E. G. Billings, A handbook of elementary 
psychobiology and psychiatry (pp. 3-22). New York, NY: MacMillan Co. 
Bitterman, M. E. (1969). Thorndike and the problem of animal intelligence. American 
Psychologist, 24 (3), 258-261. 
Blondel, V. D., Guillaume, J., Lambiotte, R., & Lefebvre, E. (2008). Fast unfolding of 
communities in large networks. Journal of Statistical Mechanics: Theory and Experiment 
, 1-12. 
Brandes, U. (2001). A Faster Algorithm for Betweenness Centrality. Journal of Mathematical 
Sociology, 25 (2), 163-177. 
Buckley, K. W. (1989). Mechanical Man. New York, NY, USA: The Guilford Press. 
Network Analysis of the JCP  147 
 
 
 
Burkhardt, R. W. (1987). The Journal of Animal Behavior and the Early History of Animal 
Behavior Studies in America. Journal of Comparative Psychology, 101 (3), 223-230. 
Burnham, J. C. (1971). Eugene S. Mills. George Trumbull Ladd, pioneer American psychologist. 
Journal of the History of the Behavioral Sciences, 7 (2), 197-198. 
Burnham, J. C. (1968). On the Origins of Behaviorism. Journal of the History of the Behavioral 
Sciences, 4 (2), 143-151. 
Cachel, S. (1990). Partisan Primatology. American Journal of Primatology, 22, 139-142. 
Carmichael, L. (1959). Karl Spencer Lashley, Experimental Psychologist. Science, 129 (3360), 
1410-1412. 
Carr, H. (1927). The interpretation of the animal mind. The Psychological Review, 34 (2), 87-
106. 
Cartmill, M. (1991). Book Review: Primate Visions: Gender, Race, and Nature in the World of 
Modern Science. International Journal of Primatology, 12 (1), 67-75. 
Clark, D. O. (2005). From Philosopher to Psychologist: The early career of Edwin Ray Guthrie, 
Jr. History of Psychology, 8 (3), 235-254. 
Cohen, D. (1979). J. B. Watson The Founder of Behaviourism: A Biography. Boston, MA, USA: 
Routledge & Kegan Paul Ltd. 
Deese, J. (1973). In memoriam, Winthrop Niles Kellogg, 1898-1972. The Psychological Record, 
23, 423-425. 
DeGrandpre, R. J., & Buskist, W. (2000). Behaviorism and neobehaviorism. In A. E. Kazdin 
(Ed.), Encyclopedia of Psychology (pp. 388-393). Washington, DC: American 
Psychological Association. 
Department History. (2013). Retrieved August 16, 2013, from Department of Psychology: 
http://www.psych.umn.edu/about/history.html 
Dewey, J. (1896). The reflex arc concept in psychology. Psychological Review, 3 (4), 357-370. 
Dewsbury, D. A. (1991). "Psychobiologist". American Psychologist, 46 (3), 198-205. 
Dewsbury, D. A. (1996). A History of Division 6. In D. A. Dewsbury (Ed.), Unification Through 
Division: Histories of the Divisions of the American Psychological Association (Vol. 1, 
pp. 41-66). Washington, DC: American Psychological Association. 
Dewsbury, D. A. (1998). Animal Psychology in Journals, 1911-1927: Another Look at the 
Snark. Journal of Comparative Psychology, 112 (4), 400-405. 
Dewsbury, D. A. (1979). C. Lloyd Morgan: Something old that's often new. PsycCRITIQUES, 
24 (9), 677-680. 
Network Analysis of the JCP  148 
 
 
 
Dewsbury, D. A. (1984). Comparative Psychology in the Twentieth Century. Stroudsburg, PA: 
Hutchinson Ross Publishing. 
Dewsbury, D. A. (1989). Comparative psychology, ethology, and animal behavior. Annual 
Review of Psychology, 40, 581-602. 
Dewsbury, D. A. (1993). On Publishing Controversy: Norman R. F. Maier and the Genesis of 
Seizures. American Psychologist, 48 (8), 869-877. 
Dewsbury, D. A. (2010). Psychology's shadows: A public and private view of controversy. 
Monitor on Psychology, 41 (1), 34. 
Dewsbury, D. A. (2002). The Chicago Five: A Family Group of Integrative Psychobiologists. 
History of Psychology, 5 (1), 16-37. 
Dorcus, R. M. (1950). Knight Dunlap: 1875-1949. The American Journal of Psychology, 63 (1), 
114-119. 
Dukes, W. F. (1960). The snark revisted. The American Journal of Psychology, 15, 157. 
Dunlap, K. (Ed.). (1917). Announcement. Psychobiology, 1, 1. 
Dunlap, K. (1917). Editorial. Psychobiology, 1 (1), 1. 
Fausto-Sterling, A. (1990). Essay Review: Primate Visions, A Model for Historians of Science? 
Journal of the History of Biology, 23 (2), 329-333. 
Freeman, L. C. (1979). Centrality in Social Networks Conceptual Clarification. Social Networks, 
1 (3), 215-239. 
Garvey, C. R. (1929). List of American psychology laboratories. Psychological Bulletin, 26 (11), 
652-660. 
Ghiselli, E. E., Beach, F. A., Pickerell, A. G., & Rosenzweig, M. R. (1978). David Krech, 
Psychology: Berkeley. In 1978, University of California: In Memoriam (pp. 99-101). 
Berkeley, CA: University of California. 
Gould, S. J. (2002). The structure of evolutionary theory. Cambridge, MA: The Belknap Press of 
Harvard University Press. 
Gray, P. H. (1962). Douglas Alexander Spalding: The First Experimental Behaviorist. The 
Journal of General Psychology, 67 (2), 299-307. 
Gray, P. H. (1967). Spalding and his influence on research in developmental behavior. Journal of 
the History of the Behavioral Sciences, 3 (2), 168-179. 
Gray, P. H. (1968-1969). The early animal behaviorists, prelegomenon to ethology. Isis, 59, 372-
383. 
Gray, P. H. (1955). The Yerkes Laboratories. Scientific American, 192 (2), 67-77. 
Network Analysis of the JCP  149 
 
 
 
Green, C. D. (2009). Darwinian Theory, Functionalism, and the First American Psychological 
Revolution. American Psychologist, 64 (2), 75-83. 
Grossett, D., & Poling, A. (1982). THE STATUS OF RATTUS: RATS AS SUBJECTS IN 
ARTICLES PUBLISHED IN JOURNAL OF COMPARATIVE AND 
PHYSIOLOGICAL PSYCHOLOGY FROM 1969 THROUGH 1981. Psychological 
Reports, 51, 969-970. 
Gumenik, W. E., & Levitt, J. (1968). The von Restorff effect as a function of difference of the 
isolated item. The American Journal of Psychology, 81, 247-252. 
Hahn, E. (1971). On the side of apes. New York, NY: Arena Books. 
Haraway, D. J. (1989). Primate Visions: Gender, Race, and Nature in the World of Modern 
Science. New York: Routledge. 
Hastorf, A. H. (2004). HISTORY OF THE DEPARTMENT OF PSYCHOLOGY. Retrieved 
August 19, 2013, from Stanford University: Department of Psychology: 
http://www.stanford.edu/dept/psychology/cgi-bin/drupalm/historyofdepartment 
Hebb, D. O. (1959). Karl Spencer Lashley: 1890-1958. The American Journal of Psychology, 72 
(1), 142-150. 
Herrick, C. J. (1907). A Study of the Vagal Lobes and Funicular Nuclei of the Brain of the 
Codfish. Journal of Comparative Neurology & Psychology, 17, 67-87. 
Herrick, C. L. (Ed.). (1910). Editorial announcement. Journal of Comparative Neurology and 
Psychology, 20, 625-626. 
Herrick, C. L. (Ed.). (1981). Introduction. Journal of Comparative Neurology, 1, i. 
Hilgard, E. R. (1994). Calvin Perry Stone. Washington, DC: National Academy of Sciences. 
Hirsch, J., & Tryon, R. C. (1956). Mass screening and reliable individual measurement in the 
experimental behavior genetics of lower organisms. Psychological Bulletin, 53, 402-410. 
Hovland, C. I. (1952). Clark Leonard Hull. The Psychological Review, 59 (5), 347-349. 
Hull, C. L. (1952). Clark L. Hull. In E. G. Boring, H. Werner, H. S. Langfeld, & R. M. Yerkes 
(Eds.), A History of Psychology in Autobiography (Vol. 4, pp. 143-162). Worcester, MA: 
Clark University Press. 
Hull, C. L. (1943). Principles of behavior. New York, NY: Appleton-Century-Crofts. 
Innis, N. K. (1992). Tolman and Tryon: Early Research on the Inheritance of the Ability to 
Learn. American Psychologist, 47 (2), 190-197. 
Johnston, T. D. (2003). Three Pioneers of Comparative Psychology in America, 1843-1890: 
Lewis H. Morgan, John Bascom, and Joseph LeConte. History of Psychology, 6 (1), 14-
51. 
Network Analysis of the JCP  150 
 
 
 
Joncich, G. (1968). E. L. Thorndike: The psychologist as professional man of science. American 
Psychologist, 23 (6), 434-446. 
Jones, R. H. (2013). Analysis & the Fullness of Reality: An Introduction to Reductionism & 
Emergence. Jackson Square Books. 
Jones, R. H. (2000). Reductionism: Analysis and the Fullness of Reality. Bucknell University 
Press. 
Kaiser, D. (2012). Booms, Busts, and the World of Ideas: Enrollment Pressures and the 
Challenge of Specialization. Osiris, 27, 276-302. 
Kellogg, W. N. (1938). The Indiana Conditioning Laboratory. The American Journal of 
Psychology, 51 (1), 174-176. 
Kellogg, W. N., & Kellogg, L. A. (1933). The Ape and the Child; a Study of Environmental 
Influence upon Early Behavior. New York: Whittlesey House. 
Kinnaman, A. J. (1902). Mental Life of two Macacus Rhesus Monkeys in Captivity. The 
American Journal of Psychology, XIII, 98-148, 173-218. 
Knight, M. (1994). Darwinian functionalism: A cognitive science paradigm. The Psychological 
Record, 44 (2), 271. 
Koch, H. L. (1955). Harvey A. Carr. The Psychological Review, 62 (2), 81-82. 
Krech, D. (1974). David Krech. In G. Lindzey (Ed.), A history of psychology in autobiography 
(Vol. VI, pp. 221-250). Englewood Cliffs, NJ: Prentice-Hall Inc. 
Krech, D. (1959). Karl Friedrich Muenzinger: 1885-1958. The American Journal of Psychology, 
72 (3), 477-479. 
Krech, D., Ghiselli, E. E., & Tuddenham, R. D. (1974). Egerton L. Ballachey, Psychology: 
Berkeley. In 1974, University of California: In Memoriam (pp. 5-6). Berkeley, CA: 
University of California. 
Kuklick, B. (2004). Philosophy at Yale in the century after Darwin. History of Philosophy 
Quarterley, 21 (3), 313-336. 
Lindzey, G. (1987). Calvin Springer Hall (1909-1985). American Psychologist, 42 (2), 185. 
Lockard, R. B. (1971). Reflections on the fall of comparative psychology: Is there a message for 
us all? American Psychologist, 26 (2), 168-179. 
Lockard, R. B. (1968). The albino rat: a defensible choice or a bad habit. American Psychologist, 
23, 734-742. 
Logan, C. (2001). "[A]re Norway Rats...Things?" Diversity Versus Generality in the Use of 
Albino Rats in Experiments on Development and Sexuality. Journal of the History of 
Biology, 34, 287-214. 
Network Analysis of the JCP  151 
 
 
 
Logan, C. (2005). The Legacy of Adolf Meyer's Comparative Approach: Worcester Rats and the 
Strange Birth of the Animal Model. Integrative Physiological & Behavioral Science, 40 
(4), 169-181. 
Maienschein, J., & Laubichler, M. D. (2010). The Embryo Project: An Integrated Approach to 
History, Practices, and Social Contexts of Embryo Research. Journal of the History of 
Biology, 43 (1), 1-16. 
Maier, N. R. (1939). Studies of abnormal behavior in the rat. New York, NY: Harper. 
Meyer, A. (1915). The justification of psychobiology as a topic of the medical curriculum. 
Psychological Bulletin, 12, 328-329. 
Miles, W. R. (1930). On the history of research with rats and mazes: a collection of notes. 
Journal of Genetic Psychology, 3, 324-337. 
Mills, J. A. (1998). Control: A history of behavioral psychology. New York, NY: New York 
University Press. 
Misiak, H., & Sexton, V. S. (1966). History of Psychology: An Overview. New York: Grune & 
Stratton. 
Mitman, G. (1993). Cinematic Nature: Hollywood Technology, Popular Culture, and the 
American Museum of Natural History. Isis, 84 (4), 637-661. 
Moore, K. G. (1949). Knight Dunlap. The Psychological Review, 56 (6), 309-310. 
Moretti, F. (2005). Graphs, Maps, Trees: Abstract Models for a Literary History. London: 
Verso. 
Morgan, C. L. (1894). Introduction to comparative psychology. New York: Scribner. 
O'Donnell, J. M. (1979). The crisis of experimentalism in the 1920s: E.G. Boring and his uses of 
history. American Psychologist, 34, 289-295. 
O'Donnell, J. M. (1985). The origins of behaviorism: American Psychology. 1870-1920. New 
York, NY, USA: New York University Press. 
O'Kelly, L. I. (1979). Paul Thomas Young: 1892-1978. The American Journal of Psychology, 92 
(3), 551-553. 
Olds, J., & Milner, P. (1954). Positive reinforcement produced by electrical stimulation of septal 
area and other regions of rat brain. Journal of Comparative and Physiological 
Psychology, 47, 419-427. 
Pate, J. L., & Fowler, R. D. (2005). Paul Shaffer Siegel (1918-2002). American Psychologist, 60 
(3), 260. 
Pettit, M. (2010). The problem of raccoon intelligence in behaviourist America. The British 
Journal for the History of Science,43(3), 391-421. 
Network Analysis of the JCP  152 
 
 
 
Pettit, M. (2012). The Queer Life of a Lab Rat. History of Psychology, 15 (3), 217-227. 
Pettit, M., Serykh, D., & Green, C. D. (forthcoming/2015). Multispecies networks: Visualizing 
the psychological research of the Committee for Research in Problems of Sex. Isis . 
Pillsbury, W. B. (1955). Harvey A. Carr: 1873-1954. The American Journal of Psychology, 68 
(1), 149-151. 
Porter, J., Johnson, S. B., & Granger, R. G. (1981). The Snark is still a Boojum. Comparative 
Psychology Newsletter, 1 (5), 1-3. 
Rosenzweig, R. (2003). Scarcity of Abundance? Preserving the Past in a Digital Era. The 
American Historical Review, 108 (3), 735-762. 
Rosvold, H. E. (1955). Calvin Perry Stone: 1892-1954. The American Journal of Psychology, 68, 
326-329. 
Rumbaugh, D. M. (1997). The psychology of Harry F. Harlow: a bridge from radical to rational 
behaviorism. Philosophical Psychology, 10 (2), 197-210. 
Rutherford, A. (2009). Beyond the box: B. F. Skinner?s technology of behavior from laboratory 
to life, 1950s-1970s. Toronto, ON: University of Toronto Press. 
Samelson, F. (1977). World War I intelligence testing and the development of psychology. 
Journal of the History of the Behavioral Sciences, 13 (3), 274-282. 
Schneirla, T. C. (1952). Basic correlations and coordinations in insect societies with special 
reference to ants. In P. P. Grasse (Ed.), Structure et physiologie des societes animales 
(pp. 247-269). Paris: Centre National de la Recherece Scientifique. 
Schneirla, T. C. (1946). Contemporary American animal psychology in perspective. In P. L. 
Harriman (Ed.), Twentieth Century Psychology (pp. 306-316). New York: Philosophical 
Library. 
Scott, J. P. (1973). The Organization of Comparative Psychology. Annals of the New York 
Academy of Sciences, 223, 7-40. 
Sears, R. R. (1982). Harry Frederick Harlow (1905-1981). American Psychologist, 37 (11), 
1280-1281. 
Shettleworth, S. (2009). The evolution of comparative cognition: Is the snark still a boojum? 
Behavioural Processes, 80 (2), 210-217. 
Simpson, G. G. (1953). The Baldwin effect. Evolution, 7 (2), 110-117. 
Small, W. (1901). Experimental study of the mental processes of the rat: II. The American 
Journal of Psychology, 12, 206-239. 
Small, W. S. (1900). An experimental study of the mental processes of the rat. The American 
Journal of Psychology, 11 (2), 133-165. 
Network Analysis of the JCP  153 
 
 
 
Smith, M. J. (1986). Realist Thought from Weber to Kissinger. Baton Rouge, LA: Louisiana 
State University Press. 
Sokal, M. M. (1997). Baldwin, Cattell and the Psychological Review: a collaboration and its 
discontents. History of the Human Sciences, 10 (1), 57-89. 
Sokal, M. M. (1990). G. Stanley Hall and the institutional character of psychology at Clark 1889-
1920. Journal of the History of the Behavioral Sciences, 26, 114-124. 
Solem, A., & McKeachie, W. J. (1979). Norman R. F. Maier (1900-1977). American 
Psychologist, 34 (3), 266-267. 
Spence, K. W. (1942). Theoretical Interpretations of Learning. In F. A. Moss (Ed.), Comparative 
Psychology (rev. ed.) (pp. 280-329). New York, NY: Prentice-Hall Inc. 
Stone, C. P. (1921). Notes on Light Discrimination in the Dog. Journal of Comparative 
Psychology, 1 (5), 413-431. 
Templin, M. C. (1968). John E. Anderson: 1893-1966. Child Development, 39 (3), 657-670. 
Thorndike, E. L. (1898). Animal intelligence: An experimental study of the associative processes 
in animals. New York, NY: Columbia University Press. 
Thorndike, E. L. (1899b). Do Animals Reason? Popular Science Monthly, LV, 480-490. 
Thorndike, E. L. (1899a). The instinctive reaction of young chicks. Psychological Review, 6 (3), 
282-291. 
Thorndike, E. L. (1901). The Intelligence of Monkeys. Popular Science Monthly, LIX, 273-279. 
Thurma, B. D. (1932). The response of the white rat to tonal stimuli. Journal of Comparative 
Psychology, 13 (1), 57-86. 
Tolman, E. C. (1922). A new formula for behaviorism. The Psychological Review, 29, 44-53. 
Tolman, E. C. (1948). Cognitive maps in rats and men. Psychological Review, 55 (4), 189-208. 
Tolman, E. C. (1951). Collected papers in psychology. Berkeley, CA: University of California 
Press. 
Tsang, Y. C. (1938). Hunger motivation in gastrectomized rats. Journal of Comparative 
Psychology, 26 (1), 1-17. 
Vanderplas, J. M. (1997). Marion E. Bunch (1902-1995). American Psychologist, 52 (2), 176. 
Warden, C. J. (1928). The development of modern comparative psychology. Quarterly Review of 
Biology, 4, 486-522. 
Warden, C. J., & Warner, L. H. (1927). The development of animal psychology in the United 
States during the past three decades. Psychcological Review, 34 (3), 196-205. 
Network Analysis of the JCP  154 
 
 
 
Watson, J. B. (1903). Animal Education--The Psychical Development of the White Rat. Oxford, 
England: Univ. Press. 
Watson, J. B. (1908). Imitation in Monkeys. Psychological Bulletin, 5, 169-178. 
Watson, J. B. (1906). The need of an experimental station for the study of certain problems in 
animal behavior. Psychological Bulletin, 3 (5), 149-156. 
Webster, S., & Coleman, S. R. (1992). Contributions to the history of psychology: LXXXVI. 
Hull and his critics: The reception of Clark L. Hull's behavior theory, 1943-1960. 
Psychological Reports, 70, 1063-1071. 
Whitely, P. L. (1976). A New Name for an Old Idea? A Student of Harvey Carr Reflects. 
Journal of the History of the Behavioral Sciences, 12, 260-274. 
Winterer, C. (2012). Where is the America in the Republic of Letters? Modern Intellectual 
History, 9 (3), 597-623. 
Yerkes, R. M. (1934, November 2). Letter to Knight Dunlap . Robert M. Yerkes Papers, 
Manuscripts and Archives, Yale University Library, New Haven, CT. 
Yerkes, R. M. (1930). Robert Mearns Yerkes: Psychobiologist. In C. Murchison (Ed.), A history 
of psychology in autobiography (pp. 381-407). Worcester, MA: Clark University Press. 
Yerkes, R. M. (1943). The Yale Laboratories of Primate Biology. Scientific Monthly, New York, 
56, 287-290. 
Young, P. T. (1978). Discrepancy and the Affective Processes. Motivation and Emotion, 2 (1), 
35-44. 
Zusne, L. (1975). Names in the history of psychology: A biographical sourcebook. Oxford, 
England: Hemisphere. 
  
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Appendix A (Tables) 
Table 1 ? Organisms (1911-1950) 
Degree Weighted Degree 
Rat (348) Rat (747) 
Human (127) Human (185) 
Monkey (39) Monkey (61) 
Cat (36) Dog (55) 
Dog (35) Chimpanzee (54) 
Chimpanzee (27) Cat (42) 
Chicken (26) Chicken (34) 
Guinea Pig (17) Pigeon (27) 
Pigeon (16) Guinea Pig (22) 
Mice (12) Ant (18) 
Rabbit (11) Mice (15) 
Bird (11) Bird (15) 
Frog (8) Wasp (13) 
Wasp (8) Rabbit (11) 
Ant (8) Frog (8) 
 
Table 2 ? Scientists (1911-1950) 
Degree Weighted Degree 
R.M. Yerkes (8) N.R.F. Maier (25) 
H.F. Harlow (7) C.P. Stone (21) 
V.E. Shelford (7) M.E. Bunch (16) 
A.H. Maslow (7) H.F. Harlow (15) 
C.P. Stone (6) H.M. Johnson (15) 
S.B. Vincent (6) K.S. Lashley (14) 
S.J. Holmes (6) W.S. Hunter (13) 
W.N. Kellogg (6) A.H. Maslow (12) 
F.T. Perkins (5) K.F. Muenzinger (12) 
K.S. Lashley (5) R.M. Yerkes (12) 
Network Analysis of the JCP  156 
 
 
 
H. Frings (4) P.S. Siegel (12) 
G.V. Hamilton (5) F.A. Beach (11) 
W.F. Grether (5) K. Dunlap (11) 
A.S. Pearse (4) P.T. Young (11) 
K. Dunlap (4) W.N. Kellogg (11) 
 
Table 3 ? Organisms (1911-1930) 
Degree Weighted Degree 
Human (71) Rat (119) 
Rat (70) Human (100) 
Cat (14) Monkey (17) 
Chicken (13) Chicken (16) 
Dog (11) Dog (15) 
Monkey (11) Cat (14) 
Guinea Pig (7) Guinea Pig (9) 
Rabbit (7) Bird (9) 
Bird (6) Wasp (7) 
Fly (5) Rabbit (7) 
Wasp (5) Fly (5) 
Beetle (5) Ant (5) 
Frog (4) Dove (5) 
Paramecium (4) Beetle (5) 
Fish (4) Frog (4) 
 
Table 4 ? Organisms (1931-1950) 
Degree Weighted Degree 
Rat (293) Rat (628) 
Human (61) Human (85) 
Monkey (30) Chimpanzee (50) 
Chimpanzee (25) Monkey (45) 
Dog (24) Dog (40) 
Cat (24) Cat (28) 
Chicken (14) Pigeon (24) 
Pigeon (14) Chicken (18) 
Guinea Pig (10) Guinea Pig (13) 
Mice (10) Ant (13) 
Bird (5) Mice (12) 
Pig (4) Wasp (6) 
Network Analysis of the JCP  157 
 
 
 
Rabbit (4) Bird (6) 
Wasp (4) Pig (5) 
Turtle (4) Horse (5) 
 
Table 5 ? Institutions (1911-1950) 
Degree Weighted Degree 
Harvard (22) California (96) 
Chicago (22) Hopkins (95) 
Wisconsin (21) Chicago (72) 
Johns Hopkins (15) Yale (70) 
California (12) Wisconsin (63) 
Yale (12) Harvard (55)