Cooperation and Punishment

Punishment can support cooperative behavior in a group, but requires coordination. In an era in which the “tragedy of the commons” has acquired new meaning on a global scale, social scientists are beginning to find hope in human nature. True, we are self-interested creatures capable of destroying the habitats that support us as we each focus on getting our share of the global commons before others beat us to it. Yet Homo sapiens could never have populated the planet and mastered complex technologies and organizational forms had nature not also made us sensitive to one another's regard. Both field studies and laboratory experiments depict humans as willing to cooperate when convinced that others are doing the same and that at least some will incur costs to sanction cheating. On page 613 in this issue, Janssen et al. (1) show that communication among members of a group is key to establishing cooperation and using punishment effectively, and on page 617, Boyd et al. (2) provide a model of how signaling (a stylized kind of communication) could have allowed punishment and cooperation to evolve.