Customary law has been criticized from very different angles. Rational choice theorists claim that what looks like custom is nothing but self-interest. Positivists doubt that anything beyond consent assumes the force of law. In this paper, we adopt an experimental approach to test these claims....

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...