ABSTRACT
The causes, consequences, and neurophysiology of punishment have received increasing attention in recent years. Punishment often occurs in social environments when trust is not reciprocated or when people given an opportunity to be cooperative choose to be selfish instead. In such cases, punishment can stem from formal contracts that specify specific sanctions for specific types of behavior. Often though, punishment is spontaneous, informal, and even costly to the punisher. Here we review and discuss aspects of what is known about human motives for punishment. By way of background, this section briefly discusses research on effects, both negative and positive, of formal and informal punishment on cooperation in groups.
