Abstract

How does Sober-Wilson group selection explain the possibility of the evolution of altruism, as modeled by cooperation in the Prisoner’s Dilemma? The essential point is that if the parameters of the model are just right, group structure can generate positive correlation of interactions between cooperators. If positive correlation is strong enough, cooperation can evolve; if not it cannot. This is true whether the positive correlation is generated by a group selection model or in some other way.