CAMBRIDGE, England — Ever wonder why watching someone vomit on TV makes you feel like you just might, too? Seeing something disgusting literally makes our stomachs turn as it changes the electrical rhythm in our muscles, according to a new study.
Scientists at the University of Cambridge say that changes in our stomach muscles could explain why we automatically turn away from disgusting images, such as rotting food, bodily waste, or creepy crawlies.
“We’ve known for some time that when you see something disgusting, your stomach muscles’ electrical signals become dysregulated, which in some cases causes people to feel sick or their stomach to turn. You’re then likely to avoid that thing,” says study author Dr. Camilla Nord, from the MRC Cognition and Brain Sciences Unit at the university, in a statement.
While feelings of disgust are natural responses that helped early humans avoid diseases, for some people, it can become a mental health issue, as they cannot control their impulses. Domperidone, a commonly prescribed anti-nausea medicine, could also help people who struggle to face gruesome sights, the researchers say.
Electrical rhythms can become abnormal when we are feeling nauseated, hungry, or too full. They can even make us throw up when we feel a strong revulsion to something. Domperidone stabilizes electrical signals in our stomach muscles, which normally help move food through the digestive tract.
For the study, a group of 25 volunteers aged 18 to 35 was randomly divided into two groups. One group was given domperidone and the other was prescribed a placebo. Volunteers were shown a series of images before taking their pills, while the researchers tracked their eye movements. Not all the images were unpleasant, some were neutral, such as a picture of buttons or a scarf. The experiment was then repeated 30 minutes after the volunteers had taken their tablets.
An incentive was then provided: Volunteers were told that if they looked at a disgusting image for four to eight seconds, they would receive 25 pence (approximately 35 cents) and hear the “ka-ching!”sound of a cash register. A final round was carried out without an incentive and volunteers were asked to rate how disgusting they found the images.
While initially the pills made little difference, after being given an incentive, people who had taken domperidone spent “significantly longer” looking at the disgusting images. On average, people spent five-and-a-half seconds longer looking at neutral images by the end of the study. But under the influence of domperidone, the difference was only two-and-a-half seconds, the researchers also found.
“What we’ve shown here is that when we steady the stomach’s electrical signals, people become less avoidant of a disgusting image after engaging with it. Changes in the stomach’s rhythm led to reduced disgust avoidance in our study – and so the stomach’s rhythm must be one cause of disgust avoidance in general,” says Nord.
Finding a medical treatment is important, as people do not build up an immunity to disgusting images over time, according to the researchers.
“In another recent study, we showed that we do not become immune to looking at disgusting images, a fact supported by the placebo condition in this new study. This is one reason why treating pathological disgust by exposure is often unsuccessful. Our research suggests domperidone may help,” explains co-author Dr. Edwin Dalmaijer.
But other incentives may be necessary for the pills to work, as the findings suggest.
“We’ve shown that by calming the rhythms of our stomach muscles using anti-nausea drugs, we can help reduce our instinct to look away from a disgusting image. But just using the drug itself isn’t enough: overcoming disgust avoidance requires us to be motivated or incentivized. This could provide us with clues on how we can help people overcome pathological disgust clinically, which occurs in a number of mental health conditions and can be disabling.”
The study’s findings are published in the journal Current Biology.
SWNS reporter Tom Campbell contributed to this report.