Impaired judgment of harmful intent is linked with damage to prefrontal cortex

Published: Wednesday, March 24, 2010 - 14:08 in Psychology & Sociology

New research provides insight into the region of the brain that underlies our tendency to condemn failed attempts to harm and forgive harms that are accidental. The study, published by Cell Press in the March 25 issue of the journal Neuron, underscores the importance of the ventromedial prefrontal cortex (VMPC) for making moral judgments about harmful intent. Previous neuropsychological and neuroimaging studies implicated the VMPC in emotional responses to harmful actions, where the actor intends to cause harm and does cause harm. However, these studies left unclear whether the VMPC plays a necessary role in evaluating harmful intentions or harmful outcomes.

"To address this question, we probed moral judgment in patients with adult-onset bilateral damage to the VMPC using scenarios that critically disentangle the contributions of intentions and outcomes to moral judgment," explains lead study author Dr. Liane Young from the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology.

Dr. Young and colleagues observed that study participants who had VMPC damage judged attempted harms as more morally permissible than control subjects did. The authors also found that the pattern of moral judgments delivered by VMPC patients represented a reversal of the normal pattern of moral judgments, in that attempted harms were judged less harshly than accidental harms. For example, the VMPC group judged that attempting but failing to poison someone was more permissible than accidentally poisoning someone.

Taken together, the findings demonstrate that patients with damage to the VMPC judge actions primarily on the basis of the actions' outcomes. "In conjunction with prior work on the role of the VMPC in emotional processing, these results further suggest that an emotional response to harmful intent is crucial for condemning failed attempts," concludes Dr. Young. "Given the critical role of intent in moral judgment, and social cognition more generally, understanding the neural basis of how intent is processed will be essential in helping us understand human moral judgment."

These observations are particularly fascinating with respect to their relation to common legal principles. For example, without a fully functional VMPC, the principle of "mens rea" (guilty mind) may be applied quite differently. Instead, the notion of "no harm, no foul" may be more significant in guiding legal decisions.

Source: Cell Press


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