Soft on crime: Patients with ventromedial prefrontal cortex damage allocate reduced third-party punishment to violent criminals.

The human impulse to punish those who have unjustly harmed others (i.e., third-party punishment) is critical for stable, cooperative societies. Punishment selection is influenced by both harm outcome and the intent of the moral agent (i.e., the offender's knowledge of wrongdoing and desire that the prohibited consequence occur). We allocate severe punishments to those who commit violent crimes and milder punishments to those who commit non-violent crimes; and we allocate severe punishments to criminals who have malicious intent and milder punishments to criminals who lack malicious intent. Prior research has indicated that aversive, emotional responses of third-party judges may influence punishment allocation, as increased negative emotion correlates with more punitive punishments. Here, we show that patients with damage to the ventromedial prefrontal cortex (vmPFC; a region necessary for the normal generation of emotion), compared to other neurological patients and healthy adult participants, allocate more lenient third-party punishment to criminals who commit emotionally-evocative, violent crimes. By contrast, patients with vmPFC damage did not differ from comparison participants on punishment allocation for non-emotional, non-violent crimes. These results demonstrate the necessity of the vmPFC for the integration of emotion into third-party punishment decisions, and indicate that negative emotion influences third-party punishment allocation particularly for scenarios involving physical harm to another.

Arrested development: early prefrontal lesions impair the maturation of moral judgement.

Learning to make moral judgements based on considerations beyond self-interest is a fundamental aspect of moral development. A deficit in such learning is associated with poor socialization and criminal behaviour. The neural systems required for the acquisition and maturation of moral competency are not well understood. Here we show in a unique sample of neurological patients that focal lesions involving ventromedial prefrontal cortex, acquired during development, result in an abnormally egocentric pattern of moral judgement. In response to simple hypothetical moral scenarios, the patients were more likely than comparison participants to endorse self-interested actions that involved breaking moral rules or physically harming others in order to benefit themselves. This pattern (which we also found in subjects with psychopathy) differs from that of patients with adult-onset ventromedial prefrontal cortex lesions--the latter group showed normal rejection of egocentric rule violations. This novel contrast of patients with ventromedial prefrontal cortex lesions acquired during development versus during adulthood yields new evidence suggesting that the ventromedial prefrontal cortex is a critical neural substrate for the acquisition and maturation of moral competency that goes beyond self-interest to consider the welfare of others. Disruption to this affective neural system early in life interrupts moral development.