There is now an extensive literature on "gift exchange" showing that when principals and agents can trade "gifts" (rewards that should not emerge in a competitive equilibrium), exchange becomes more efficient. However, it is not obvious how gift exchange should be organized if the principal's...

We define social reciprocity as the act of demonstrating one's disapproval, at some personal cost, for the violation of widely-held norms (e.g., don't free ride). Social reciprocity differs from standard notions of reciprocity because social reciprocators intervene whenever a norm is violated...

The enforcement of social norms often requires that unaffected third parties sanction offenders. Given the renewed interest of economists in norms, the literature on third party punishment is surprisingly thin, however. In this paper, we report on the results of an experiment designed to...