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J Comp Psychol. 2007 May;121(2):145-55.

Chimpanzee (Pan troglodytes) anticipation of food return: coping with waiting time in an exchange task.

Author information

1
Ethology Research, Animal Science Department, Biomedical Primate Research Centre, Rijswijk, Netherlands. valerie.dufour@c-strasbourg.fr

Abstract

Despite controversial expectations that animals achieve reciprocal altruism, it is unclear if nonhuman species possess the necessary cognitive abilities. For reciprocal altruism, individuals must anticipate the loss of a commodity and accept a delay before some return. The authors investigated the abilities of 5 chimpanzees (Pan troglodytes) to cope with increasing waiting duration in exchange tasks. Subjects had to keep a small cookie before returning it to a human partner to obtain a larger piece. For a piece 2, 4, or 8 times the size of the small piece, 3 of the 5 subjects waited for up to 4 min. For a piece 40 times larger, 4 of the 5 subjects waited up to 8 min. At long time lag, renouncement to wait occurred earlier than predicted by subjects' general waiting capacity, suggesting that the decision to wait was based on a trade-off between reward quantity and expected costs of the waiting duration. Chimpanzees could anticipate a delayed reward at a time scale of several minutes. If this reflects a cognitive limit in chimpanzees' anticipation capacity, reciprocal altruism by keeping track of costs and benefits over extended periods may be unlikely in chimpanzees.

PMID:
17516793
DOI:
10.1037/0735-7036.121.2.145
[Indexed for MEDLINE]

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