title: Bonobos exhibit delayed development of social behavior and cognition relative to chimpanzees.
abstract: Phenotypic changes between species can occur when evolution shapes development. Here, we tested whether differences in the social behavior and cognition of bonobos and chimpanzees derive from shifts in their ontogeny, looking at behaviors pertaining to feeding competition in particular. We found that as chimpanzees (n = 30) reached adulthood, they became increasingly intolerant of sharing food, whereas adult bonobos (n = 24) maintained high, juvenile levels of food-related tolerance. We also investigated the ontogeny of inhibition during tasks that simulated feeding competition. In two different tests, we found that bonobos (n = 30) exhibited developmental delays relative to chimpanzees (n = 29) in the acquisition of social inhibition, with these differences resulting in less skill among adult bonobos. The results suggest that these social and cognitive differences between two closely related species result from evolutionary changes in brain development.
authors.affiliation: Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138, USA. wobber@fas.harvard.edu <wobber@fas.harvard.edu>
authors.forename: Victoria
authors.initials: V
authors.lastname: Wobber
authors.forename: Richard
authors.initials: R
authors.lastname: Wrangham
authors.forename: Brian
authors.initials: B
authors.lastname: Hare
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001921:Brain / Q000254:growth & development; D003071:Cognition; D005247:Feeding Behavior; D005260:Female; D007858:Learning; D008297:Male; D008960:Models, Psychological; D019974:Pan paniscus / Q000254:growth & development* / Q000523:psychology*; D002679:Pan troglodytes / Q000254:growth & development* / Q000523:psychology*; D012919:Social Behavior; D013045:Species Specificity