disgust

Italian disgusto — bad taste, displeasure — combines dis- (reversal) and gusto (taste, from Latin gustus). The Italian word entered French as dégout and then English in the early 17th century. The original meaning was literal: a distasteful flavor, something that makes you spit out what you have put in your mouth. The metaphorical extension to moral repugnance came quickly.

Darwin, in The Expression of the Emotions in Man and Animals (1872), observed that disgust is universally expressed by the same facial configurations across cultures — the curled upper lip, the lowered brow, the gagging response. He proposed disgust was adaptive: it evolved to prevent ingestion of contaminated food. The facial expression that communicates 'this is disgusting' is derived from the pre-swallowing rejection of spoiled matter.

Psychologist Paul Rozin in the 1980s and 90s extended the analysis: disgust expanded beyond food to encompass bodily fluids, death, moral violations, and social transgressions. The same neural circuits that evolved to protect from contaminated food were recruited to signal contamination by taboo behaviors. To find something morally disgusting is to feel it as physically nauseating — the same mechanism, different trigger.

Disgust is politically potent. Research by Jonathan Haidt found that political conservatives tend to experience moral disgust more intensely and frequently than liberals — disgust sensitivity predicts certain political orientations. The emotion of protecting the mouth's purity became an emotion protecting social purity. The taste receptor became a political instrument.