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.