Research Focus

Cognitive set occurs when a known or familiar solution blocks a better alternative.


The Learned Strategy - Direct Strategy task is a nonverbal, non-arithmetic measure of cognitive flexibility. Unlike typical metrics, the LS-DS task does not require subjects to switch away from a learned strategy. Subjects learn, across three Training levels, how to select Square1 and then Square2 of a demonstration and then select the Triangle.  This Square1-Square2-Triangle solution constitutes the Learned Strategy (demonstrated by the white hand).  However, in PROBE trials, the Triangle appears alongside the demonstration thereby allowing subjects to either continue to employ their Learned Strategy or adopt the more efficient Direct Strategy (i.e. just selecting the Triangle; demonstrated by the yellow hand). 

Sarah's dissertation research utilized the LS-DS task to compare cognitive set (becoming stuck in a response strategy) between primate species and to assess the developmental and cultural influences on humans' ability to break cognitive set. It has now also been used as a measure of optional-switch cognitive flexibility in capuchins and rhesus macaques (Watzek, Pope, & Brosnan 2019).

Sarah's current research explores how cognitive set evolved within the primate lineage and how it varies across human cultures. 


 Cognitive Flexibility in Nonhuman Primates

To assess a likely evolutionary trajectory of cognitive set within the primate species, she created the nonverbal, computerized LS-DS task and tested baboons', chimpanzees', and humans' abilities to forsake a learned solution strategy in order to adopt a more efficient alternative.  

Perceptual and Conceptual Influences

During her research, perceptual influences on cognitive set have also been investigated by tracking subjects’ eye-movements during LS-DS task performance and conceptual influences have been manipulated across multiple studies.

Cross-Cultural Influences

To explore the role of culture and educational background on cognitive flexibility in humans, Sarah compared susceptibility to cognitive set on the LS-DS task between American participants and the semi-nomadic Himba of northern Namibia.  See Fieldwork for more information.

Additional Research Interests

Evolution of Imitation
Sarah is also interested in the association between social cognition and imitation in humans and nonhuman primates. She recently published a study which sought to understand the neural underpinnings of imitation in chimpanzees by teaching them to play a ‘Do As I Do’ imitation game and then identifying changes in white matter connectivity between Pre- and Post- training brain images, compared to controls.