The physiological basis of psychological disgust and moral judgments

TRACY, J.L., STECKLER, C.M., & HELTZEL, G.

JOURNAL OF PERSONALITY AND SOCIAL PSYCHOLOGY

Abstract: To address ongoing debates about whether feelings of disgust are causally related to moral judgments, we pharmacologically inhibited spontaneous disgust responses to moral infractions and examined effects on moral thinking. Findings demonstrated, first, that the antiemetic ginger (Zingiber officinale), known to inhibit nausea, reduces feelings of disgust toward nonmoral purity-offending stimuli (e.g., bodily fluids), providing the first experimental evidence that disgust is causally rooted in physiological nausea (Study 1). Second, this same physiological experience was causally related to moral thinking: ginger reduced the severity of judgments toward purity-based moral violations (Studies 2 and 4) or eliminated the tendency for people higher in bodily sensation awareness to make harsher moral judgments than those low in this dispositional tendency (Study 3). In all studies, effects were restricted to moderately severe purity-offending stimuli, consistent with preregistered predictions. Together, findings provide the first evidence that psychological disgust can be disrupted by an antiemetic and that doing so has consequences for moral judgments.