We compare a partners condition where the same small group of subjects plays arepeated public good game to astrangers condition where subjects play this game in changing group formations.Subjects in the partners conditioncontribute from the first period on significantly more to the public good...

Most of the literature on the evolution of human pro-sociality looks at reasons why evolution made us not play the Nash equilibrium in prisoners' dilemmas or public goods games. We suggest that in order to understand human morality, and human prosocial behaviour, we should look at reasons why...