Disgust comes from the Latin word distaste, meaning to dislike or disrelish. In her book That’s Disgusting: Unravelling the Mysteries of Repulsion (W.W. Norton, 2012), Rachel Herz describes physical disgust as ‘a scientific amalgamation of terror management and the avoidance of pathogens and oral incorporation’.

In early development, the infant learns to curl the upper lip and wrinkle the nose, an unconscious expression of disgust that is a protective mechanism, closing the mouth and nostrils to limit ingestion of harmful pathogens. With its specific physiological and neurological response, disgust also manifests in an urgent need to move away, excessive salivation, nausea and even vomiting. In the 1860s, Charles Darwin conjectured that disgust could have an evolutionary purpose, preventing our ancestors from eating rotten or contaminated food that might result in poisoning. Those with a more acute sense of revulsion survived, while those with less sensitivity did not. In the 1990s, researchers started to examine disgust in psychological and behavioural studies, identifying a number of types of disgust and further investigating how these influence the way we behave.