Scientists Who Study Disgust Claim the Emotion Is Based in Eating

avoiding poisonous foods may be the root of disgust

By Jonny Lupsha, Wondrium Staff Writer

There may be a scientific reason that we smell spoiled food and jerk our heads away. Disgust is one of the most basic emotions in the psyche and serves many purposes. Disgust may be a survival instinct.

Man with a disgust expression on his face after smelling food
At its most basic function, the emotion of disgust serves to keep us from harm. Photo Motortion Films / Shutterstock

Virtually all living creatures need some form of nourishment to survive, and humans are no exception. Even beyond our own personal preferences, there may be scientific grounding for our aversion to certain foods—and everything else, from clogged shower drains to dirty diapers.

Some psychologists who study the emotion, like Dr. Paul Rozin of the University of Pennsylvania, claim that it traces back to our basic survival instincts, aiming to keep us safe from doing things like introducing poisonous substances to our insides or needlessly exposing ourselves to pathogens, and that it could explain everything.

How did this view come about? In his video series Understanding Human Emotions, Dr. Lawrence Ian Reed, Clinical Assistant Professor of Psychology at New York University, explains a model of disgust proposed by three psychologists who studied the emotion and published its preeminent study, including Dr. Rozin himself.

The Willies All Over

“One of the things that makes disgust so interesting, and so difficult to conceptualize and study, is that it is very heterogenous,” Dr. Reed said. “That is, disgust is elicited in response to a wide range of stimuli. You might be disgusted after stepping in dog poop on the street and tracking it into your home. You might also be disgusted by a cockroach scurrying across your kitchen table.”

Disgust takes a fascinating turn when we don’t just ascribe it to a single object. What if, Dr. Reed asked, that same cockroach happened to cross some food that you had been preparing to eat? In all likelihood, that food is virtually unaffected by the cockroach’s presence, but many of us would now find it inedible. Apart from food, we may be disgusted by other concepts, like voting for a political candidate we despise or having romantic physical contact with a relative.

Each of these stimuli, he said, elicits disgust, and so any conceptualization of disgust must account for these very different types of stimuli. Enter Dr. Rozin’s study.

“One of the most widely accepted models of disgust was proposed by Paul Rozin, Jonathan Haidt, and Clark McCauley,” he said. “Many would claim that their model is the gold standard and I think that most in the field see it as the model that all others are compared to. At its heart, the model is based on an evolutionary and, thus, functional viewpoint of disgust.

“It states that there is a ‘core disgust’ that is elicited in response to potentially harmful or distasteful objects in the environment that might be unhealthy for us to be exposed to.”

Types of Heebie-Jeebies

Rozin, Haidt, and McCauley’s model also posits that there are four kinds of disgust, three of which adapted from the idea of core disgust.

Core disgust protects the body from contaminated, or being harmed by, “potentially noxious and/or distasteful stimuli,” as Dr. Reed put it. It’s usually elicited by living things like parasites, pathogens, and corpses; as well as things associated with living things, such as saliva, feces, urine, semen, and sweat.

The second kind of disgust serves what’s called the “animal-reminder function.”

“The function of this type of disgust is to protect the soul by denying our animal nature,” Dr. Reed said. “Here, denying our animal nature also denies our mortality. This type of disgust is elicited by sex, bad hygiene, death, puncturing the skin, and objects entering the body; it’s also elicited by body envelope violations, like gore, wounds, and disfigurement.”

The third kind of disgust is interpersonal, which we feel upon contact with undesirable persons, or the prospect thereof. It serves to protect the social order, Dr. Reed said. Finally, the fourth type of disgust serves the moral function by making us feel averse to compromising our morals.

This model serves as the gold standard of disgust, though recently, other psychologists have identified potential shortcomings and things that aren’t explained by it. As is often the case with science and medicine, it’s an evolving study that is subject to change.

Cockroaches, though, will always be creepy to me.

Edited by Angela Shoemaker, Wondrium Daily