Author ORCID Identifier

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Sarah Brosnan

Second Advisor

Sarah Barber

Third Advisor

Michael Beran

Fourth Advisor

Marcela Benítez

Fifth Advisor

Erin Tone


Pressure, a feature of a situation in which an individual’s outcome is heavily reliant on their ability to perform, is a potential source of stress that might impact an individual’s cognitive performance. An understanding of why some individuals “choke,” or fail to perform, under pressure has been largely ignored when considering the cognition of animals. My previous work provided some of the first evidence that other species were sensitive to pressure, and tufted capuchin monkeys varied significantly in their likelihood of failure on trials that were cued to be particularly high pressure. In this dissertation, I argue that individual responses to pressure are a critical missing aspect of our understanding of cognition in other species. In Chapter 2, I explored how the size of the available stimulus pool used in a delayed-matching-to-sample task engaged different memory processes and how pressure influenced those different memory processes. Capuchins performed better when they were able to use familiarity memory to solve the task as opposed to working memory, but the monkeys were no more or less likely to perform poorly under high pressure in the working memory-based condition, as opposed to the condition that could be solved using familiarity memory. In Chapter 3, I developed a method to test pressure effects using a sequential response task and developed a method to non-invasively sample salivary cortisol, in order to assess if the hypothalamic-pituitary-adrenal (HPA) stress response was related to performance under pressure. Monkeys were more likely to fail to perform on high-pressure trials as compared to low-pressure trials on the sequential response task. Neither salivary nor fecal cortisol were related to performance, and performing an anxiolytic behavior that increases oxytocin did not ameliorate the performance deficits associated with pressure, suggesting that further work needs to be done to understand the interaction between task demand and stress response in producing responses to pressure. Overall, this dissertation provides further evidence that non-human species can be sensitive to pressure while performing, but also highlights that task demands and individual differences play a key role in whether non-human animals “choke.”


File Upload Confirmation


Available for download on Sunday, December 08, 2024