Do Great Apes Choose to Choose?: An Investigation of Preference for Computer-Provided Choice in Orangutans (Pongo abelii)

This dissertation examined orangutans preference for computer touchscreen-provided choice and their capacity to recognize the content of 2-D pictures. Investigation of these factors is important for advancing our understanding of orangutan cognition and the development of Animal-Computer Interaction systems that provide captive great apes environmental enrichment through provision of choice. Using a concurrent chain procedure presented on a touchscreen computer, the first experiment examined three orangutans intrinsic valuation of choice by assessing preference for free- or forced- choice when neither choice options nor outcomes vary. Initial results indicated a preference for free-choice across all participants. However, in two control conditions, preferences varied, suggesting a weaker tendency to exercise choice than species previously tested. Motivated by subjects difficulty learning associations between application icons and food rewards, a series of three experiments investigated five orangutans capacity to spontaneously recognize the content of novel pictorial stimuli by assessing if they demonstrated the same hierarchical preferences for food and pictures of food. Results indicated that orangutans only recognized picture content in certain formats and that they were more proficient in print than in digital mediums. Having confirmed that orangutans could recognize digital food images in a single format, this format was employed in the final pair of experiments to examine whether increasing the fidelity of the experimental choice paradigm elicited stronger free-choice preferences. This research question was investigated in a stepwise manner: Experiment 1 provided varied choices options that led to a single outcome and Experiment 2 varied both the choice options and outcomes. Results indicated a preference for free-choice in orangutans, but one that can be overwhelmed by competing factors and depend on the advantage afforded by it. Moreover, findings indicated that for orangutans, the strength and quality of preference for free-choice can be affected by the fidelity of the choice paradigm and vary between individuals. In light of these results, I suggest that preference for choice may be more accurately conceptualized along a spectrum rather than a dichotomy of preference for choice or lack thereof.