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...

Experimental studies show that the Nash equilibrium and its refinements are poor predictors of behavior in non-cooperative strategic games. Cooperation models, such as ERC and inequality aversion, yield superior predictions compared to the standard game theory predictions. However, those models...