We consider the formation and long-run stability of cooperative groups in a social dilemma situation where the pursuit of individual interests conicts with the maximization of social welfare. The adaptive play model of Young (1993) is applied to a group formation game where voluntary...

We present a simple model of voluntary groups in a collective action problem where individuals differ in their willingness to cooperate. The heterogeneity of individuals' preferences generally yields multiple equilibrium groups with different levels of cooperation. Voluntary participation in a...