Evolution of fairness: cultural variability.

J. HENRICH ET AL. (“Markets, religion, community size, and the evolution of fairness and punishment,” Research Articles, 19 March, p. 1480) have shown that market integration and participation in world religion covary with fairness. The authors suggest that their results support cultural evolution theories and contradict the hypothesis that successful social interactions in largescale societies arise to a large extent from an evolved psychology. We believe that their conclusion is based on too simple a view of human morality. Much research in behavioral economics supports the idea that humans have a sense of fairness that aims to equilibrate exchanges among individuals. In economic games where money needs to be distributed, for instance, people carefully respect everyone’s rights over the stake: If the common good is produced by a single person, she is granted more rights over the money (1, 2); similarly, the most productive partner during the joint production phase is favored (3, 4).