Conditional cooperation is an important factor in voluntary cooperation. Fehr and Schmidt (1999) show that in public good games conditional cooperation among rational players is feasible if cooperators are sufficiently inequality averse and if there are not too many free riders. The derived...

We experimentally examine how the incentive to defect in a social dilemma affects conditional cooperation. In our first study we conduct online experiments in which subjects play eight Sequential Prisoner's Dilemma games with payoffs systematically varied across games. We find that few second...