Informal punishment of non-cooperators

According to an influential theory known as "strong reciprocity", humans cooperate at high levels due to the rise of altruistic punishers, that is, individuals who not only cooperate themselves but also informally punish non-cooperators. Strong reciprocity theory assumes that this punishment is costly to the punisher but beneficial to the group, that is, the punisher behaves altruistically. The theory further assumes that by engaging in this individually costly but group-beneficial behavior, punishers gain a good reputation. The aim of my dissertation is to critically examine the empirical validity of these assumptions through a series of experimental studies. Overall, I find that the assumptions of strong reciprocity theory are not supported. (1) Punishment of non-cooperators does not seem to be driven by punishers having the group's interest at heart. In fact, I find that punishers in economic cooperative games tend not to be more cooperative than non-punishers. Punishers also tend to punish both non-cooperators and cooperators. I conclude that punishers seem to be characterized by being generally punitive rather than being generally altruistic. (2) Punishers of non-cooperators do not seem to gain a good reputation in general. Rather, informal social norms about the use of punishment seem to restrict it more than encourage it. Moreover, people who face the choice of whether to punish a non-cooperator seem not to tend to think of punishing as the moral thing to do.

My conclusion of these empirical results is that strong reciprocity theory paints an incorrect picture of the psychology of informal punishment of non-cooperators. I argue that this theory likely goes wrong already when it takes cooperative situations as its starting point, and that a better approach would be to assume that there is a more general psychology of informal punishment. I sketch what such an approach would entail.