Last time around on Clever Apes we dipped into realms of science that some might consider disgusting. Now we turn to the science of disgust itself.
What is disgust, and where does it come from? There are a few places where scientists can look for clues, starting with what disgusts people. We did a decidedly unscientific survey of kids at the Museum of Science and Industry, and the results line up pretty well with what actual experts say. They break out in a few categories: bodily secretions (blood, vomit, feces, puss), animals that could carry disease (insects, vermin), and certain foods (pot pies … don’t ask). A few common ones our pint-sized sample group didn’t bring up, thankfully, include corpses and incest.
Then there’s the strong physiological response to disgust, especially nausea and facial contortions. According to psychologist Paul Rozin, that evidence indicates that disgust has its origins in avoiding toxic agents in stuff we eat. Evolutionary anthropologist Dan Fessler adds that the feeling then gets generalized to all sorts of other things, from sexual mores all the way up to our deepest moral convictions.
One place where Rozin and Fessler part ways: Rozin, one of the forefathers of disgust theory, believes disgust serves to distance us from our most animalistic behaviors: dying, procreating, eating, pooping. By this view disgust is existential armor, protecting us from having to come to terms with our bestial nature. Fessler is skeptical of that argument (in part because of his own experimental results). He argues the disgust response has become a way to define and protect boundaries – from national borders right down to the boundaries of our own bodies.
In any case, disgust seems to be a basic human emotion, written into our nature by evolution, shaping and shaped by our culture.