A competitive nonverbal false belief task for children and apes
Article first published online: 10 FEB 2009
DOI: 10.1111/j.1467-7687.2008.00793.x
© 2009 The Authors. Journal compilation © 2009 Blackwell Publishing Ltd
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How to Cite
Krachun, C., Carpenter, M., Call, J. and Tomasello, M. (2009), A competitive nonverbal false belief task for children and apes. Developmental Science, 12: 521–535. doi: 10.1111/j.1467-7687.2008.00793.x
Publication History
- Issue published online: 8 JUN 2009
- Article first published online: 10 FEB 2009
- Received: 8 August 2007Accepted: 7 May 2008
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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.

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