The jurisdiction of the man within: Introspection, identity, and cooperation in a public good experiment

According to Adam Smith (1790), human selfishness can be restrained by introspection. We test the effect of introspection on people's willingness to cooperate in a public good game. Drawing on the concept of identity utility (George A. Akerlof and Rachel E. Kranton, 2000), we show theoretically that introspection may enhance cooperation by increasing the relative cost of deviating from one's self-image. Experimentally, we induce introspection through the elicitation of (normative) expectations. Our results show that introspection causally increases cooperation. Both home-grown idealism and the experiences with the cooperativeness of the environment predict individual cooperativeness throughout the game.