A veto game played by baboons: a challenge to the use of the Prisoner's Dilemma as a paradigm for reciprocity and cooperation

Abstract

According to a widely accepted paradigm, cooperation among animals resembles an iterated, two-player Prisoner's Dilemma game. In this symmetrical game the two players have equivalent strategic options. Decisions are based only on information obtained in similar interactions with the same player in the past. The Prisoner's Dilemma model ignores the social organization within which cooperation occurs. This paper advocates a set of alternative models based on N-player coalition games that apply especially to collaboration (that is, cooperation and reciprocity) within social groups. The model takes into account the effect of competition for the favours of suitable partners. In Coalition games negotiations are possible and the strategic options of the players can be unequal. An example of a Coalition game, the Veto game, is illustrated by patterns of coalition formation among adult males in a group of wild baboons Papio c. cynocephalus.