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Generalized Reciprocity in RatsClaudia Rutte, Michael Taborsky*
1 Department of Behavioral Ecology, Institute of Zoology, University of Berne, Berne, Switzerland
The evolution of cooperation among nonrelatives has been explained by
direct, indirect, and strong reciprocity. Animals should base the decision
to help others on expected future help, which they may judge from past
behavior of their partner. Although many examples of cooperative behavior
exist in nature where reciprocity may be involved, experimental evidence
for strategies predicted by direct reciprocity models remains
controversial; and indirect and strong reciprocity have been found only in
humans so far.
Here we show experimentally that cooperative behavior of female rats is
influenced by prior receipt of help, irrespective of the identity of the
partner.
Rats that were trained in an instrumental cooperative task (pulling a
stick in order to produce food for a partner) pulled more often for an
unknown partner after they were helped than if they had not received help
before. This alternative mechanism, called generalized reciprocity,
requires no specific knowledge about the partner and may promote the
evolution of cooperation among unfamiliar nonrelatives.
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the full text:
http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371%2Fjournal.pbio.0050196.