What humans find disgusting is proving irresistible to
researchers exploring the evolutionary value of revulsion.
Disgust is the Cinderella of emotions. While fear, sadness and
anger, its nasty, flashy sisters, have drawn the rapt attention of
psychologists, poor disgust has been hidden away in a corner, left
to muck around in the ashes.
No longer. Disgust is having its moment in the light as
researchers find that it does more than cause that sick feeling in
the stomach. It protects human beings from disease and parasites,
and affects almost every aspect of human relations, from romance to
In several new books and a steady stream of research papers,
scientists are exploring the evolution of disgust and its role in
attitudes toward food, sexuality and other people.
Paul Rozin, a psychologist who is an emeritus professor at the
University of Pennsylvania and a pioneer of modern disgust research,
began researching it with a few collaborators in the 1980s, when
disgust was far from the mainstream. "It was always the other
emotion," he said. "Now it's hot."
It still won't wear glass slippers, which may be just as well,
given the stuff it has to walk through. Nonetheless, its reach takes
disgust beyond the realms of rot and excrement.
Speaking last week from a conference on disgust in Germany,
Valerie Curtis, a self-described "disgustologist" from the London
School of Public Hygiene and Tropical Medicine, described her
favorite emotion as "incredibly important."
She continued: "It's in our everyday life. It determines our
hygiene behaviors. It determines how close we get to people. It
determines who we're going to kiss, who we're going to mate with,
who we're going to sit next to. It determines the people that we
shun, and that is something that we do a lot of."
It begins early, she said: "Kids in the playground accuse other
kids of having cooties. And it works, and people feel shame when
disgust is turned on them."
Some studies have suggested that political conservatives are more
prone to disgust than liberals are. And it is clear that what people
find disgusting they often find immoral, too.
It adds to the popularity of disgust as a subject of basic
research that it is easier to elicit in an ethical manner than anger
or fear. You don't have to insult someone or make anyone afraid for
his or her life -- a bad smell will do the trick. And disgust has
been relatively easy to locate in the brain, where it frequents the
insula, the amygdala and other regions.
"It is becoming a model emotion," said Jonathan Haidt of the
University of Virginia, a disgust pioneer with Mr. Rozin.
And the research may have practical benefits, including clues to
obsessive compulsive disorder, some aspects of which -- like
excessive hand washing -- look like disgust gone wild.
Conversely, some researchers are trying to inspire more disgust
at dirt and germs to promote hand washing and improve public health.
Ms. Curtis is involved in efforts in Africa, India and England to
explore what she calls "the power of trying to gross people out."
One slogan that appeared to be effective in England in getting
people to wash their hands before leaving a bathroom was, "Don't
bring the toilet with you."
Disgust was not completely ignored in the past. Charles Darwin
tackled the subject in "The Expression of the Emotions in Man and
Animals." He described the face of disgust, documented by Guillaume-
Benjamin Duchenne in his classic study of facial expressions in
1862, as if one were expelling some horrible tasting substance from
"I never saw disgust more plainly expressed," Darwin wrote, "than
on the face of one of my infants at five months, when, for the first
time, some cold water, and again a month afterwards, when a piece of
ripe cherry was put into his mouth." His book did not contain an
image of the infant, but fortunately YouTube has numerous videos of
babies tasting lemons. …