title: Chimpanzees and bonobos differ in intrinsic motivation for tool use.
abstract: Tool use in nonhuman apes can help identify the conditions that drove the extraordinary expansion of hominin technology. Chimpanzees and bonobos are our closest living relatives. Whereas chimpanzees are renowned for their tool use, bonobos use few tools and none in foraging. We investigated whether extrinsic (ecological and social opportunities) or intrinsic (predispositions) differences explain this contrast by comparing chimpanzees at Kalinzu (Uganda) and bonobos at Wamba (DRC). We assessed ecological opportunities based on availability of resources requiring tool use. We examined potential opportunities for social learning in immature apes. Lastly, we investigated predispositions by measuring object manipulation and object play. Extrinsic opportunities did not explain the tool use difference, whereas intrinsic predispositions did. Chimpanzees manipulated and played more with objects than bonobos, despite similar levels of solitary and social play. Selection for increased intrinsic motivation to manipulate objects likely also played an important role in the evolution of hominin tool use.
authors.affiliation: Anthropological Institute and Museum, University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland.|Department of Archaeology &Anthropology, University of Cambridge, Pembroke Street, CB2 3QG Cambridge, United Kingdom.
authors.forename: Kathelijne
authors.initials: K
authors.lastname: Koops
authors.affiliation: Primate Research Institute, Kyoto University, Aichi 484-8506, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Furuichi
authors.affiliation: Primate Research Institute, Kyoto University, Aichi 484-8506, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D005260:Female; D008297:Male; D009042:Motivation; D019974:Pan paniscus; D002679:Pan troglodytes