Large group size promotes the evolution of cooperation in the mutual-aid game

摘要

Our society is based on group cooperation, but this remains an unsolved problem from the viewpoint of evolutionary biology and the social sciences. Group cooperation is often studied through the public goods game, and it has been shown that large group size never promotes the evolution of cooperation. We consider the mutual-aid game, in which one member of the group is chosen randomly as the aid recipient, and other members decide whether to help the recipient. This game can describe the early stage of insurance provision in England, for example. With reference to existing indirect reciprocity studies, we investigate what promotes the evolution of cooperation in the mutual-aid game by means of replicator equations and agent-based simulations.