How easily grossed out are you? Your sensitivity to disgust reveals more about you than you'd probably be comfortable with, from how you'll vote in this election to your potential to be a cold-blooded killer.
Who do you think has a stronger stomach: a liberal or a conservative? Who is the tougher party?
The knee-jerk answer to this question might lean toward the latter, because conservative political ideologies – on the whole – are perceived by both sides as taking a harder line. But what brain circuits are stirring beneath those hardline decisions?
An international team of researchers conducted two studies (involving more than 31,000 people in total) and found a positive relationship between sensitivity to disgust and political conservatism. "Across both samples, contamination disgust, which reflects a heightened concern with interpersonally transmitted disease and pathogens, was most strongly associated with conservatism," the study reports.
Disgust is a sliding scale, and we’re all grossed out by different things. Some of us shudder at the thought of seeing blood. Some draw the line at foul smells. There are people who are disgusted by homosexuality and there are people are disgusted by homophobia. And there are a few groups who have almost no sensitivity to disgust at all.
Science journalist Kathleen McAuliffe knows a lot about disgust. She took us on a wonderful tour of parasites here, and in the video above she tackles the link between visceral disgust and moral disgust. It’s hard for the average person to fathom how someone can decide to kill in cold blood, and also physically carry out the act. But research has found that cold-blooded killers have damage to the brain circuits involved in the disgust response, which explains why these people are less squeamish about not just the moral quandary of taking a life but are also quite comfortable carrying out the grizzly act.
McAuliffe points to another group of individuals who have similarly impaired disgust circuits: people with Huntington’s disease. This is a genetically transmitted neurodegenerative disease, and those with it are unable to recognize expressions of disgust in others, and don’t tend to react to foul smells, sights or tastes. People with Huntington’s also have impaired fear recognition, as the two areas are closely related in the brain.
Which brings us back to conservative political ideologies, particularly immigration aversion. McAuliffe notes that there is a link between germophobia and xenophobia, as evidenced by a study of 2000 Danish people and 1200 Americans, where the data showed that opposition to immigration increased in direct proportion to the disgust sensitivity of the individual.
If you want to see where you sit on the disgust sensitivity scale, there’s a quiz for your amusement over here.
Kathleen McAuliffe's book is This Is Your Brain on Parasites: How Tiny Creatures Manipulate Our Behavior and Shape Society.