Does inappropriate behavior hurt or stink? The interplay between neural representations of somatic experiences and moral decisions

Embodied models suggest that moral judgments are strongly intertwined with first-hand somatic experiences, with some pointing to disgust, and others arguing for a role of pain/harm. Both disgust and pain are unpleasant, arousing experiences, with strong relevance for survival, but with distinctive sensory qualities and neural channels. Hence, it is unclear whether moral cognition interacts with sensory-specific properties of one somatic experience or with supramodal dimensions common to both. Across two experiments, participants evaluated ethical dilemmas and subsequently were exposed to disgusting (olfactory) or painful (thermal) stimulations of matched unpleasantness. We found that moral scenarios enhanced physiological and neural activity to subsequent disgust (but not pain), as further supported by an independently validated whole-brain signature of olfaction. This effect was mediated by activity in the posterior cingulate cortex triggered by dilemma judgments. Our results thus speak in favor of an association between moral cognition and sensory-specific properties of disgust.