Biomedical subjects

JB Silk

Publications and source records attributed to JB Silk.

3 recordsLinked to original sources

PubMed2000

Cheap talk when interests conflict.

Most evolutionary analyses of animal communication suggest that low-cost signals can evolve only when both the signaller and the recipient rank outcomes in the same order. When there is a conflict of interest between sender and receiver, honest signals must be costly. However, recent work suggests that low-cost signals can be evolutionarily stable, even when the sender and the receiver rank outcomes in different orders, as long as the interest in achieving coordination is sufficiently great. In this paper, we extend this body of work by analysing a game theory model that shows that low-cost signals can evolve when there are conflicts of interest and no interest in coordination, as long as individuals interact repeatedly. We also present an empirical example indicating that female rhesus macaques, Macaca mulatta, use honest, low-cost, vocal signals to facilitate interactions when conflicts of interest exist. Copyright 2000 The Association for the Study of Animal Behaviour.

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PubMed1999

Why are infants so attractive to others? The form and function of infant handling in bonnet macaques.

Female macaques and baboons are intensely interested in other females' infants, but provide little direct care for them. The selective factors that shape this strong attraction to neonates may differ from those that shape alloparental care in other taxa. The attraction to neonates may have evolved because (1) it enhances young females' acquisition of maternal skills, (2) it is a form of reproductive competition among females, or (3) it is a by-product of selection for appropriate maternal care. I studied patterns of infant handling in a large group of bonnet macaques, Macaca radiata, at the California Primate Research Center at the University of California, Davis. Infant handling was generally gentle and nonintrusive, although females sometimes tugged on infants. Females were more strongly attracted to infants than were males, regardless of their age. Adult females handled infants as often as subadult females did. Male and female infants were handled at equal rates, and rates of handling towards all infants declined sharply as infants matured. Infants were handled by related females at higher rates than by unrelated females, and at higher rates by higher-ranking females than by lower-ranking females. The data provide little support for the 'learning to mother' hypothesis, because older females were as interested in infants as were subadult females. Although mothers were reluctant to allow their infants to be handled, the data do not support the reproductive competition hypothesis because patterns of infant handling did not match patterns of harassment of infants. The data provide a better fit to the by-product hypothesis. Females were most strongly attracted to infants when maternal care was most critical for infant survival and females of all ages were strongly attracted to infants. Taken together, these data suggest that a strong attraction to infants is favoured by selection because females that are highly responsive to infants make good mothers. Copyright 1999 The Association for the Study of Animal Behaviour.

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PubMed1999

Male bonnet macaques use information about third-party rank relationships to recruit allies.

Social challenges may have driven the evolution of intelligence in primates and other taxa. In primates, the social intelligence hypothesis is supported by evidence that primates know a lot about their own relationships to others and also know something about the nature of relationships among other individuals (third-party relationships). Knowledge of third-party relationships is likely to play an especially important role in coalitions, which occur when one individual intervenes in an ongoing dispute involving other group members, by helping individuals to predict who will support or intervene against them when they are fighting with particular opponents, and to assess which potential allies are likely to be effective in coalitions against their opponents. To date, however, there is no evidence that primates make use of knowledge of third-party relationships when they form coalitions. Here, I show that male bonnet macaques, Macaca radiata, use information about third-party rank relationships when they recruit support from other males. Males consistently chose allies that outranked themselves and their opponents, and made such choices considerably more often than would be expected by chance alone. The analysis shows that the data do not fit simpler explanations based upon males' knowledge of their own relationships to other males or males' ability to recognize powerful allies. Copyright 1999 The Association for the Study of Animal Behaviour.

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