Direct and indirect punishment among strangers in the field

作者：Balafoutas Loukas^*; Nikiforakis Nikos; Rockenbach Bettina

来源：Proceedings of the National Academy of Sciences, 2014, 111(45): 15924-15927.

DOI：10.1073/pnas.1413170111

• cooperation
• field experiment
• indirect reciprocity
• punishment
• social norms

Many interactions in modern human societies are among strangers. Explaining cooperation in such interactions is challenging. The two most prominent explanations critically depend on individuals%26apos; willingness to punish defectors: In models of direct punishment, individuals punish antisocial behavior at a personal cost, whereas in models of indirect reciprocity, they punish indirectly by withholding rewards. We investigate these competing explanations in a field experiment with real-life interactions among strangers. We find clear evidence of both direct and indirect punishment. Direct punishment is not rewarded by strangers and, in line with models of indirect reciprocity, is crowded out by indirect punishment opportunities. The existence of direct and indirect punishment in daily life indicates the importance of both means for understanding the evolution of cooperation.

• 出版日期2014-11-11