Sean Lee

Grant Type

Dissertation Fieldwork Grant

Institutional Affiliation

George Washington U.

Grant number

Gr. 9466

Approve Date

April 25, 2017

Project Title

Lee, Sean M., George Washington U., Washington, DC - To aid research on 'Prosocial and Craniofacial Ontogeny in Wild Chimpanzees and Bonobos: A Test of the Self-domestication Hypothesis,' supervised by Dr. Carson M. Murray

Preliminary abstract: The human self-domestication hypothesis posits that selection for increased prosociality in humans resulted in a suite of feminized craniofacial traits unique among hominins due to correlated physiological mechanisms underlying prosocial behavior and craniofacial form. Bonobos (Pan paniscus) are also thought to have undergone self-domestication because they exhibit increased prosociality and feminized craniofacial traits relative to their sister-taxon, chimpanzees (Pan troglodytes). This hypothesis predicts that, in both humans and bonobos, increased prosociality and feminized craniofacial traits arise through changes in ontogeny (i.e., growth and development). However, these changes in ontogeny have not been tested between modern and fossil humans, largely because it is difficult to infer prosociality from the fossil record. My research project will compare prosocial and craniofacial ontogeny in living, wild chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), humans’ closest living relatives, to test the prediction that increased prosociality and feminized craniofacial traits in bonobos are the result of changes in the ontogeny of these traits relative to chimpanzees. Research will build on longterm behavioral and photogrammetric morphological data collection on immatures and adults at Gombe National Park, Tanzania, and the Lui Kotale Bonobo Project, Democratic Republic of Congo. Prosocial and craniofacial ontogenetic trajectories will be characterized and compared between species to determine precisely how adult differences in these traits arise. Results of this study will provide insight into how differences in these traits may have arisen between modern and fossil humans.