VALUES, EMPATHY, AND FAIRNESS ACROSS SOCIAL BARRIERS On Hotheads and Dirty Harries The Primacy of Anger in Altruistic Punishment

Recent research has shown that individuals are prepared to incur costs to punish non-cooperators, even in one-shot interactions. However, why would people punish non-cooperators with no apparent benefits for the punishers themselves? This behavior is also known as altruistic punishment.When defection is discovered, an individual evalu-ates this act as unfair,which could result in anger.We argue that althoughunfairness and anger are often intertwined, it is primarily the experience of anger and not the percep-tion of unfairness that produces altruistic punishment.We briefly present recent data in line with the hypothesis that identifies anger as the underlying mechanism of altruistic punishment. Furthermore, additional influences regarding the occurrence of altruistic punishment, e.g., intentionality of the interaction partner, the role of satisfaction, and individual differences, are discussed. Key words: altruistic punishment; anger; fairness; emotion Altruistic Punishment Scholars from both biological and social sci-ences face the long-standing problem of un-derstanding the conditions required for the emergence and maintenance of human coop-eration. Unlike other organisms, people fre-quently cooperate with genetically unrelated strangers, with people they never meet again, and when reputation gains are small or even absent. This behavior is puzzling because such cooperation can incur individual costs to con-fer benefits on unrelated others. It cannot be explained by mechanisms commonly used to explain cooperative behavior in general, e.g., nepotistic motives associated with the theory of kin selection and inclusive fitness,1 selfish motives associated with theories of direct reci-procity,2,3 indirect reciprocity based on repu