Shame and guilt are distinct negative moral emotions, although they are usually regarded as overlapping affective experiences. Of these two emotions, shame is more closely related to concerns about other people's judgment, whereas guilt is more related to concerns about one's own judgment. Although some studies have tried to identify the psychological process underlying shame as opposed to guilt, there is no clear evidence of brain regions that are specifically relevant to the experience of shame rather than guilt and, more generally, self-blame. We therefore investigated associations between individual differences in shame- and guilt-proneness and the gray and white matter structures of the brain using magnetic resonance imaging and voxel-based morphometry while controlling for associations with guilt- or shame-proneness. To accomplish this goal, we enrolled 590 healthy, right-handed individuals (338 men and 252 women; age, 20.6 ± 1.8 years). We administered a questionnaire to assess shame proneness and guilt proneness. Based on our hypothesis, we found that high shame proneness was associated with decreased regional white matter density only in the right inferior temporal pole, whereas no significant region was associated with guilt. The function of this area may be important for the underlying processes differentiating shame from guilt.
Keywords: Shame proneness; regional white matter density; right inferior temporal pole; voxel-based morphometry.