The role of orbitofrontal cortex in moral judgment

Abstract

The neural substrates of moral judgments have recently been advocated to consist of widely distributed brain networks including the orbitofrontal cortex (OFC), anterior temporal lobe and superior temporal gyrus. Moral judgments could be regarded as a conflict between the top-down rational/logical processes and the bottom-up irrational/emotional processes. Individuals with OFC damage are usually difficult to inhibit emotionally-driven outrages, thereby demonstrating severe impairment of moral judgments despite their well-preserved moral knowledge. Individuals with OFC damage frequently present with anti-social less moral behaviors. However, clinical observation indicates that some OFC patients may show "hypermoral" tendency in the sense that they are too strict to overlook other person's offense. Two representative cases with OFC damage were reported, both presented with extreme rage against others' offensive behaviors. To further elucidate the "hypermorality" of OFC patients, an experiment was performed in which patients with OFC damage and healthy control participants were asked to determine punishments for other's fictitious crimes that varied in perpetrator responsibiHty and crime severity. Individuals with OFC damage punished more strictly than healthy controls those persons for mitigating circumstances. The results are consistent with clinical observation of OFC patients' highly rigid and inflexible behaviors against third person's offense.