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Psychology (Functional Area: Developmental & Cognitive Processes)

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  • ItemOpen Access
    Orangutan Vision, Looking Preferences, and Passive Looking-Time Versus Active Touchscreen Paradigms
    (2019-07-02) Adams, Laura Catherine; MacDonald, Suzanne
    Key aspects of orangutan picture preference, looking paradigms, and vision were assessed in three manuscripts. These studies have important contributions to research on comparative vision and animal picture perception, as well as practical applications for orangutan research. The first manuscript assessed visual preferences for pictures of primates. Orangutan looking-time was coded as they watched simultaneous slideshows on two laptop computers. Orangutans preferred photographs of unfamiliar orangutans over unfamiliar humans, and familiar orangutans over unfamiliar orangutans. When comparing familiar orangutans, they preferred adults over infants, and males over females. These preferences were then compared to preferences reported across primates which show variable results, likely due to complex social factors and context. A second manuscript assessed passive looking-time and active touchscreen paradigms. Passive and active paradigms can produce discrepant results, and the validity of these paradigms had not been empirically assessed in animals. Three methods were compared: looking-time at slideshows on two laptops, a touchscreen that displayed pictures when touched, and simply holding up pairs of printed images. All three methods detected the expected preference for pictures of animals over non-animals. This can be considered evidence of the reliability of these paradigms, equivalence of passive and active methods, and support for continued use of looking-time and touchscreens in orangutan research. The final manuscript assessed the contrast sensitivity function (CSF). Orangutans were trained to select vertical or horizontal lines, and then the CSF threshold was estimated by increasing the spatial frequency and decreasing the contrast of the stimuli. Orangutan CSF was similar in shape and position on the frequency scale to those of humans and macaques, but overall sensitivity was lower. We propose that this was due to testing conditions and low motivation. Across these three manuscripts orangutans demonstrated overall vision and looking behaviour that was similar to humans, however with high variability likely due to competing interests, low motivation, and individual differences.
  • ItemOpen Access
    Exploring the Bilingual Advantage in Executive Control: Using Goal Maintenance and Expectancies
    (2016-09-20) Viswanathan, Mythili; Bialystok, Ellen B.
    Previous research has shown that bilingualism helps to offset age-related losses in certain executive processes such as inhibitory control, task switching and divided attention. The two studies presented in this dissertation investigated possible mechanisms underlying this bilingual advantage in executive control by examining the role of expectancies and goal maintenance in monolingual and bilingual younger (30 to 40 years) and older adults (60 to 80 years). In Chapter 2, the fadeout paradigm (Mayr & Liebscher, 2001) was used to examine differences in the ability to disengage from an irrelevant task cue. Testing began with single task blocks of shape and colour classifications presented separately, followed by a task switching block in which the two tasks alternated randomly. On trial 49, one of the tasks became irrelevant, leaving only a single task to perform. The critical variable was the point at which participants performance reflected this change by examining the number of trials required to return to single task block speed. Results showed that both younger and older bilinguals returned to single task block speeds sooner than monolinguals. The results were interpreted as showing that bilinguals were better able to use task cues to improve task performance and that outsourcing control to task cues may be beneficial. In Chapter 3, a dual modality classification paradigm was used to determine the speed at which two tasks could be executed at the same time as a means of measuring the ability to sustain task goals. The task required participants to simultaneously respond manually to visual stimuli and verbally to auditory stimuli. Results revealed that younger and older bilinguals showed smaller costs in responding to two tasks whereas monolinguals experienced larger delays in making their responses. Proportion analysis of dual task costs and pairs of responses revealed a bilingual advantage and did not show any age-related increases in costs. The results were interpreted as demonstrating the strength in goal maintenance in bilinguals, allowing them to establish a task goal, control interference from stimulus pairings in order to uphold the goal, and to manage multiple streams of information, and these abilities are sustained in aging.
  • ItemOpen Access
    Relation of Infants' Memory and Expectation Formation: Evidence from Anticipatory Eye Movements and Pupil Diameter Changes
    (2014-07-09) Wong Kee You, Audrey Marie Beatrice; Adler, Scott A.
    Theories have suggested that infants’ ability to form expectations and exhibiting anticipatory eye movements, highlight our memory’s function of providing a foundation upon which expectations for future events are formed. This study aimed to assess this hypothesis by investigating the relation between long-term memory and expectation formation in 3-month-old infants. Infants underwent the Visual Expectation Paradigm and after a delay of 24 hours, infants were tested with either a change in the stimuli or the same stimuli. Infants’ level of anticipatory eye movements were measured on both test days. This study also aimed to study the relation between working memory and long-term memory by investigating if temporal decay (a limitation of working memory), would affect infants’ long-term memory. To this end, this study assessed the effect of two different interstimulus intervals (ISIs) on infants’ long-term memory performance. Finally, changes in pupil diameter during encoding and retrieval were also measured.
  • ItemOpen Access
    The Influence of Cultural Context on Language Activation in Korean-English Bilinguals
    (2014-07-09) Berkes, Matthias Daniel; Bialystok, Ellen B.
    Both languages for bilinguals are jointly activated even when performance is clearly restricted to one. The present study investigated the role of cultural cues on the relative level of joint linguistic activation. Twenty-two Korean-English bilinguals were presented with a picture and an audio cue and indicated via button press whether the heard label named the depicted object while EEG was recorded. In the critical blocks, the pictures represented exemplars that were more typically English or Korean, even though both exemplars take the same name in both languages (e.g., North American soup vs. Korean soup). English or Korean labels for the same set of pictures were presented in separate blocks. Reaction times were significantly faster for trials in which the auditory stimulus correctly named the object and the language matched the cultural bias. Providing the correct label in either language significantly attenuated the N400. A late positive component (LPC) was present for trials in which the label was correct, and was more positive when viewing Korean exemplars with English audio. No differences were seen when either English or Korean pictures were paired with Korean auditory stimuli. Therefore, effects of cultural context and semantic integration appear to be separate.
  • ItemOpen Access
    Resolving Between-Language and Within-Language Competition in Bilinguals
    (2014-07-09) Chung-Fat-Yim, Ashley Kim; Bialystok, Ellen B
    Friesen et al. (2011) reported behavioural and electrophysiological differences in how monolinguals and bilinguals resolved lexical competition in a picture selection task (PST). Participants selected a named picture from two alternatives that were related semantically, phonologically, or unrelated. Both groups were slower on related pairs, but the additional RT cost on semantically-related pairs was smaller for bilinguals than for monolinguals. Importantly, monolinguals exhibited attenuated N400s for semantically-related pairs while bilinguals did not. The current study pursued these results with a homogeneous group of English-French bilinguals performing the task in both languages. Measures of executive control, language proficiency, and language production abilities were acquired to investigate their influence in resolving interlingual and intralingual competition. In both languages, semantic pairs generated longer RTs than phonological and unrelated pairs and as in the earlier study, there was no modulation of the N400. There was no evidence for a relation between the PST and the flanker task. However, a relation was found between vocabulary knowledge and the PST in the weaker language.