supply using a real effort experiment. Two results stand out. First, no one theory seems to fit the pooled data. On average … reciprocal or intrinsically motivated and, indeed, these types respond as theory would predict: reciprocators return wage gifts …

The theory of compensating differentials has proven difficult to test with observational data: the consequences of …. Instead, we construct experimental, real-effort labor markets and offer an evaluation of the theory in a controlled setting … differentials are affected by worker mobility and therefore selection. Consistent with the theory, we find that riskier firms must …