Date of Award

Spring 5-15-2019

Author's School

Graduate School of Arts and Sciences

Author's Department


Degree Name

Doctor of Philosophy (PhD)

Degree Type



Various factors are hypothesized to have contributed to the flourishing of technology during human evolution, including high-fidelity social learning, a propensity for prosocial helping, and sex differences in foraging tool use. In this research, we examined the role of these factors on the development of complex tool-using skills among wild chimpanzees (Pan troglodytes troglodytes) in the Goualougo Triangle, Republic of Congo. These apes exhibit among the most complex tool behaviors of any nonhuman animal, including the flexible use of multiple tool types and the manufacture of tools from specific raw materials, according to a particular design. Specifically, we drew upon a 15-year, longitudinal dataset to assess the acquisition of termite-gathering skills among 25 immature chimpanzees and compare these results to those for chimpanzees (Pan t. schweinfurthii) at Gombe, Tanzania; test whether tool transfers from competent to less skilled conspecifics comprise a form of teaching; and compare tool transfer behavior among chimpanzees at Goualougo to those at Gombe. Results indicate that individuals learn single before multiple tool use, and in contrast to Gombe, tool use is learned before tool manufacture. We did not detect significant sex differences in skill acquisition, but females acquired most termite-gathering skills slightly before males do, and males on average manufactured tools slightly earlier than females. At Goualougo, skilled chimpanzees, typically mothers, sometimes transfer termite-gathering tools to their offspring, and these transfers comprise a functional form of teaching. The rate of tool transfers as well as the probability of tool transfer after request are higher at Goualougo, and transfer types are more prosocial. These findings suggest that the complexity of termite-gathering among chimpanzees in the Congo Basin may influence the sequence of skill acquisition and be associated with an enhanced role for social learning. Further research is necessary to determine what drives the manifestation of sex differences in skill acquisition, and how this relates to adult sex differences in tool use. Based on these findings, I conclude that high-fidelity social learning and prosocial helping intersect to promote the transmission of complex skills between individuals, supporting the hypothesis that these factors contributed to the emergence of cumulative cultural behavior in human evolution.


English (en)

Chair and Committee

Crickette M. Sanz

Committee Members

Richard J. Smith, Elizabeth V. Lonsdorf, Krista M. Milich, Elizabeth A. Quinn,


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