Grooming, Coalitions, and Reciprocal Altruism in Primates
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JASs forum Ethics and Altruism Journal of Anthropological Sciences Vol. 85 (2007), pp. 235-236 Grooming, coalitions, and reciprocal altruism in primates Gabriele Schino Istituto di Scienze e Tecnologie della Cognizione, Consiglio Nazionale delle Ricerche, Roma e-mail: [email protected] Th e study of primate altruistic behaviours Preliminary meta-analytical data also show can help to shed light on the evolution of that primates reciprocate amount of grooming human altruism. In particular, as it provides received, that is they groom their group mates information on patterns of altruism in species in relation to the grooming received, and that that may lack advanced cognitive abilities such the degree of grooming reciprocation is inversely as the capacity for empathy and score-keeping. related to the tendency to direct grooming up Grooming and agonistic coalitions represent the hierarchy (Schino & Aureli, in preparation). two traditional examples of primate reciprocal Knowledge of these general patterns altruism (Trivers, 1971). Seyfarth (1977) of grooming distribution among primates developed an infl uential theoretical model to is to be complemented with an improved explain the distribution of grooming among understanding of the proximate mechanisms female primates. Th is model assumed females underlying reciprocal exchanges. Recent data on compete for accessing and grooming high-ranking the temporal relations between grooming and group mates in order to exchange grooming for agonistic support in Japanese macaques (Schino later support during aggressive confrontations. et al., 2007) suggest reciprocal exchanges are not Despite its enormous infl uence on the based on a short-term temporal contingency, ethological literature, data supporting Seyfarth's but much more detailed data are needed on this model were until recently scantier than generally topic. As for the cognitive basis of reciprocation, assumed. In the last few years, meta-analytical at the moment, both emotion-based and techniques have been applied to published data cognition-based proximate mechanisms on primate grooming and agonistic coalitions, have been proposed (Brosnan & de Waal, and have shown that primate grooming does 2002), but their relative prevalence is unclear. satisfy most of the assumptions and predictions Th e data reviewed above highlight that of Seyfarth's model (Schino, 2001; 2007). nonhuman primates show a variety of altruistic Primates direct their grooming preferentially to behaviours whose evolution is likely to be based, higher-ranking animals and, as a results, high- beside kin selection, on the selective mechanism ranking animals receive overall more grooming initially identifi ed by Robert Trivers (1971), that than their lower-ranking group mates. Primates is, reciprocal altruism. Th ese altruistic behaviours also compete for accessing high-ranking group are deployed strategically among group members mates, as shown by the signifi cant relation in order to maximize received return benefi ts. between the groomer's rank and its ability to Th ese observations are relevant to the evolution distribute grooming in relation to the recipient's of our own species as they provide both rank. Th is preference for grooming high- evidence that altruistic behaviour predates the ranking group mates is explained, as originally evolution of human-like cognitive abilities, and assumed by Seyfarth's model, by the exchange support to the notion that the need to navigate that occur between grooming and rank-related a complex social environment favoured the benefi ts, for example agonistic coalitions. initial evolution of improved cognitive abilities. the JASs is published by the Istituto Italiano di Antropologia www.isita-org.com 236 JASs forum: Ethics, Altruism and Evolution References Schino G., Polizzi di Sorrentino E. & Tiddi B. 2007. Grooming and coalitions in Japanese Brosnan, S.F., de Waal. F.B.M. 2002. A proximate macaques (Macaca fuscata): partner choice perspective on reciprocal altruism. Human and the time frame of reciprocation. J. Comp. Nature, 13: 129-152. Psychol., 121: 181-188. Schino G. 2001. Grooming, competition and Seyfarth R.M. 1977. A model of social grooming social rank among female primates: a meta- among adult female monkeys. J. Th eor. Biol., analysis. Anim. Behav., 62: 265-271. 65: 671-698. Schino G. 2007. Grooming and agonistic Trivers R.L. 1971. Th e evolution of reciprocal support: a meta-analysis of primate reciprocal altruism. Q. Rev. Biol., 46: 35-57. altruism. Behav. Ecol., 18: 115–120..