Co-operation and Communication in Apes and Humans

We trace the difference between the ways in which apes and humans co-operate to differences in communicative abilities, claiming that the pressure for futuredirected co-operation was a major force behind the evolution of language. Competitive co-operation concerns goals that are present in the environment and have stable values. It relies on either signalling or joint attention. Future-directed co-operation concerns new goals that lack fixed values. It requires symbolic communication and contextindependent representations of means and goals. We analyse these ways of co-operating in game-theoretic terms and submit that the co-operative strategy of games that involve shared representations of future goals may provide new equilibrium solutions.