Evolutionary altruism (defined in terms of fitness effects) exists in the context of punishment in addition to helping. We examine the proximate psychological mechanisms that motivate altruistic helping and punishment, including the effects of genetic relatedness, potential for future interactions, and individual differences in propensity to help and punish. A cheater who is a genetic relative provokes a stronger emotional reaction than a cheater who is a stranger, but the behavioral response is modulated to avoid making the transgression public in the case of cheating relatives. Numerous behavioral differences are not accompanied by emotional differences, suggesting that other psychological mechanisms dictate the specific response to emotion-provoking events. Paradoxically, there is a positive correlation between temptation to cheat and propensity to punish others for cheating, leading to a concept of "selfish punishment" that has been substantiated by a computer simulation model. This study demonstrates that fictional scenarios can provide an important methodological tool for studying the psychological basis of helping and punishment.
Available at: http://works.bepress.com/omar-eldakar/3/