COOPERATION IN PRIMATES - CRITICAL ANALYSIS OF BEHAVIORAL CRITERIA

Concerning hunting in chimpanzees, cooperation has generally been attr ibuted to the behaviour of two or more individuals acting together to achieve a common goal (Boesch and Boesch, 1989). The common goal is of ten considered as the concrete result of a common action by two or sev eral individuals. Although this result could be used as a criterion fo r cooperation, it could also be an outcome due to chance. We suggest t hat the goal, viewed as a concrete benefit shared by the partners, is not a requisite of cooperation but rather-a possible consequence of a common action largely submitted to social constraints. Individuals eng aged in a cooperative task in order to solve a problem have to exchang e information to adjust to each other's behaviour. However, evidence o f communication between partners during simultaneous cooperation is ra re. An experiment in which two chimpanzees each had to simultaneously pull a handle to get a fruit was performed. We analysed not only the c oncrete result of the partners' activity but also what the individuals took into account before pulling a handle. We tried to specify what t he chimpanzees learned by means of a series of logical propositions wh ich we were able to confront the experimental results.