Date of Award

Spring 2023

Document Type


Degree Name

Doctor of Psychology (PsyD)



Committee Chairperson

Rebecca Chancellor, PhD.

Committee Member

Aaron Rundus, PhD.

Committee Member

Angela Clarke, PsyD.


The current study aims to bring to light the critical role that play has on healthy development, not only for nonhuman primates, but also for humans. In addition to building the literature concerning social and play development among gorillas and humans, this study also hopes to promote the observation and welfare of captive gorillas. The present study conducted longitudinal observational research of a troop of captive western lowland gorillas (Gorilla gorilla gorilla) to gain insights into primate play development and how it relates to social bonding and zoological enrichment. The study followed the early infancy and juvenile years of two gorilla infants, one male and one female, housed at the Philadelphia Zoo in Philadelphia, Pennsylvania. This study used focal scanning to obtain approximately 280 hours of data across 58 nonconsecutive months, which was organized to create a frequency-based activity budget of the typical behaviors of gorilla infants. This activity budget revealed that gorilla infants engage in several styles of play for an average of 15-20% of their days. This indicates that play is a necessity in appropriate, healthy, and enriched development. These analyses are reviewed with consideration of primate personality styles and through a comparative psychology lens, offering both clinical and zoological implications.