How information about perpetrators’ nature and nurture influences assessments of their character, mental states, and deserved punishment

Evidence of perpetrators’ biological or situational circumstances has been increasingly brought to bear in courtrooms. Yet, research findings are mixed as to whether this information influences folk evaluations of perpetrators’ dispositions, and subsequently, evaluations of their deserved punishments. Previous research has not clearly dissociated the effects of information about perpetrators’ genetic endowment versus their environmental circumstances. Additionally, most research has focused exclusively on violations involving extreme physical harm, often using mock capital sentences cases as examples. To address these gaps in the literature, we employed a “switched-at-birth” paradigm to investigate whether positive or negative information about perpetrators’ genetic or environmental backgrounds influence evaluations of a perpetrator’s mental states, character, and deserved punishment. Across three studies, we varied whether the transgression involved direct harm, an impure act that caused no harm, or a case of moral luck. The results indicate that negative genetic and environmental backgrounds influenced participants’ evaluations of perpetrators’ intentions, free will, and character, but did not influence participants’ punishment decisions. Overall, these results replicate and extend existing findings suggesting that perpetrators’ supposed extenuating circumstances may not mitigate the punishment that others assign to them.