Date of Thesis

Winter 2017


Many non-human primates live in social groups in which social interactions may not just be dictated by an individual’s desired social partners but also by group structure and social constraints. For example, some monkeys may desire more social interaction with specific individuals but may be limited by rank, while others may desire less social interaction with individuals but are limited by kinship. While behavioral observations can inform which individuals an animal spends their time with, cognitive tests such as those using looking time may be required to measure these social preferences. In the present study, six subject monkeys were tested on a looking time experiment in which they viewed images of four different stimulus monkeys that varied in how much time they spent with the subject (low vs high sociality) and in who was the primary initiator of social interactions in the pair (partner vs subject initiated). This resulted in four categories of stimulus monkey per animal: HS (high social-subject initiated), HP (high social-partner initiated), LS (low social-subject initiated), and LP (low social-partner initiated). If animals are constrained in their social interactions and are unable to allocate their social time as they would like, I expected different looking time to the HP and LS condition as these are the conditions where there is a difference between aspired and actualized social relationships. Results revealed that looking time towards the HP and LS stimuli were significantly different from looking time towards the HS and LP stimulus animals. These results suggest that capuchins have constrained social relationships and may not be affiliating with desired partners due to factors other than their social preferences. Additionally, these results provide evidence that capuchins can recognize images representing familiar individuals and obtain social information from them.


Cebus apella, looking time, relationships, photograph recognition, non-human primates

Access Type

Honors Thesis (Bucknell Access Only)

Degree Type

Bachelor of Science


Animal Behavior

First Advisor

Regina Paxton Gazes