From rotten food to weeping sores, our sense of squeamishness can help save our lives. But why are some people more susceptible to disgust than others – and what does it mean?
One of the fun parts of being a disgustologist – as researchers who study the emotion of disgust sometimes call themselves – must be coming up with revolting scenarios. Repulsive enough to test a theory, but not quite so stomach-turning as to repel the people who have volunteered to take the test. In a recent study led by Prof Val Curtis, director of the environmental health group at the London School of Hygiene and Tropical Medicine, the vignettes were admirably imaginative. People were asked to rate their levels of disgust at more than 70 scenarios. These included imagining a hairless old cat rubbing up against one’s leg, stepping on a slug in bare feet, shaking hands with someone with “scabby fingers”, finding out a friend eats roadkill, finding out another attempted to have sex with a piece of fruit, and seeing “pus come from a genital sore”. And, my personal favourite, for warped imagination alone: learning your neighbour defecates in his back garden.
The findings, published this week in the Royal Society’s Philosophical Transactions B journal, reveal six categories of disgust: poor hygiene, animals that are vectors of disease (such as rats or cockroaches), sexual behaviours, atypical appearance, lesions and visible signs of infection, and food that shows signs of decay. “The fact we’ve found there is an architecture of disgust that has six components to it tells us something about the way in which emotions work,” says Curtis. “It tells us that emotions are for doing particular behaviours. The emotion of disgust is about doing certain things that avoid disease – they’re about not eating spoiled food, not sticking your fingers in somebody’s weeping sore, not having sex with somebody you know is having sex with lots of other people, not picking up cockroaches and kissing them. It confirms the hypothesis that disgust really is about avoiding infection.”