The motive matters: Experimental evidence on the expressive function of punishment

The literature on punishment and prosocial behavior has presented conflicting findings. In some settings, punishment crowds out prosocial behavior and backfires; in others, however, it promotes prosociality. We examine whether the punisher's motives can help reconcile these results through a novel experiment in which the agent's outcomes are identical in two environments, but in one the pre-emptive punishment scheme is self-serving (i.e., potentially benefits the punisher), while in the other it is other-regarding (i.e., potentially benefits a third party). We find that self-serving punishment reduces the social stigma of selfish behavior, while other-regarding punishment does not. Self-serving punishment is thus less effective at encouraging compliance and is more likely to backfire. We further show that the normative message is somewhat weaker when punishment is less costly for the punisher. Our findings have implications for the design of punishment mechanisms and highlight the importance of the punisher's motives in expressing norms.