title: A competitive nonverbal false belief task for children and apes.
abstract: A nonverbal false belief task was administered to children (mean age 5 years) and two great ape species: chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). Because apes typically perform poorly in cooperative contexts, our task was competitive. Two versions were run: in both, a human competitor witnessed an experimenter hide a reward in one of two containers. When the competitor then left the room (version A) or turned around (version B), the experimenter switched the locations of the containers. The competitor returned and reached with effort, but unsuccessfully, towards the incorrect container. Children displayed an understanding of the competitor's false belief by correctly choosing the other container to find the reward. Apes did not. However, in version A (but not version B), apes looked more often at the unchosen container in false belief trials than in true belief control trials, possibly indicating some implicit or uncertain understanding that needs to be investigated further.
authors.affiliation: Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.
authors.forename: Carla
authors.initials: C
authors.lastname: Krachun
authors.forename: Malinda
authors.initials: M
authors.lastname: Carpenter
authors.forename: Josep
authors.initials: J
authors.lastname: Call
authors.forename: Michael
authors.initials: M
authors.lastname: Tomasello
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D002675:Child, Preschool; D032882:Comprehension / Q000502:physiology*; D004193:Discrimination Learning / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D019974:Pan paniscus / Q000523:psychology*; D002679:Pan troglodytes / Q000523:psychology*; D011340:Problem Solving / Q000502:physiology*; D011581:Psychological Tests