Although leave-taking in non-human species has been preliminarily investigated in a few species, the mechanisms driving encounter ends remain unstudied. In 1976 Albert and Kessler published a landmark paper, outlining theories about what drives social encounter ends and providing a framework of internal and external motivations leading to separation. This framework has been underused in aiding our understanding of how proximate mechanisms for separation drive leave-taking and offers a valuable opportunity to better understand how separation and behavior relate to one another. Having previously identified leave-taking in wild chacma baboons (Papio ursinus), in the current paper, we apply this framework to their leave-taking to better understand how the motivations to leave impact leave-taking. Using GLMMs with binomial error structure, our results suggest that internal motivations to end interactions are better predictors of orientation-shifting behavior when compared to external motivations. We argue that these results validate the use of Albert and Kessler's framework across species and suggest that leave-taking may have evolved to signal internal drivers of interaction ends, a behavior that has become elaborated in human behavior.
D. Kay (Tue,) studied this question.