Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Neuroscience Institute

First Advisor

William Hopkins

Second Advisor

Joel Fagot

Third Advisor

Adrien Meguerditchian

Fourth Advisor

David Washburn


By applying learned rules, humans are able to accurately solve many problems with minimal cognitive effort; yet, this sort of habit-based problem solving may readily foster a type of cognitive inflexibility termed ‘cognitive set’. Cognitive set occurs when an alternative – even more efficient – strategy is masked by a known, familiar solution. In this research, I explored how cognitive set differs between primate species and across human cultures, using a nonverbal computerized ‘LS-DS’ task, which measures subjects’ ability to depart from a three-step, learned strategy (LS) in order to adopt a more efficient, one-step, direct strategy (DS or ‘the shortcut’). First, I compared baboons’, chimpanzees’, and humans’ abilities to break cognitive set and found that all baboon and chimpanzee subjects used the DS shortcut when it became available; yet, humans exhibited a remarkable preference for the LS. Next, in an effort to elucidate how cognitive set occludes alternative strategies, I tracked human participants’ eye movements to identify whether better solutions are a) visually overlooked or b) seen but disregarded. Although human subjects saw the shortcut, they did not use it until their conceptualization of the problem constraints were altered. Lastly, to further distinguish between perceptual and conceptual influences on cognitive set, I compared shortcut-use between Westerners and the semi-nomadic Himba of northern Namibia. This study found that susceptibility to cognitive set varied across human cultures and presented further evidence that problem conceptualization, and not perceptual processing, influences individuals’ ability to break set and use the alternative. Overall, this research provides a novel comparison of cognitive flexibility within the primate lineage and across human cultures. The implications for set-promoting influences, including the potentially mechanizing problem-solving methods typical of Western education, are discussed.