Conditional cooperation: the effect of the marginal per capita return and the group size

Abstract

We studied the behaviour of decisions of contribution to the public good using two questionnaires using a variant of the strategic method. Specifically, we analysed the effect on subjects decisions of a change in the marginal per capita return from 0.6 to 0.9 two subjects and games of four subjects. We find that for groups of two subjects, 50% can be classified as conditional cooperators. However, we do not obtain this result for groups of four subjects. With groups of four subjects only about 30% behave as conditional cooperators.