If You Find Cockroaches Gross, That's a Good Thing — Here's Why

By Korin Miller | Yahoo Health

Your severe aversion to those scurrying brown bugs is actually healthy, research says. (Photo: Getty Images/Saul Herrera/Yahoo)

You feel disgusted when you smell rotten food and grossed out when you spot a cockroach. But it turns out, there’s a scientific reason why humans experience disgust: It’s good for your health.

Researchers from Canada’s British Columbia University and the University of California, Los Angeles, recently released new research that delves more into our “behavioral immune system,” a mechanism that’s stimulated by seeing, hearing, touching, or smelling something that could cause harm to our bodies — which we then experience as disgust.

For example, you probably would avoid using a filthy public restroom because it grosses you out. But that’s actually your behavioral immune system at play — you avoid the dirty bathroom because it disgusts you, and you’re saving your body from having to fight off harmful bacteria you may come into contact with while using the bathroom.

But disgust doesn’t always prompt an “ick” response — it can also cause a person to be turned off by the idea of certain behaviors and consequently avoid them. In the new study, scientists found that disgust and the behavioral immune system can impact a wide range of our behaviors, including how we interact socially.

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Among other things, researchers discovered that when people think that they’re more vulnerable to getting sick, they’re “disgusted” by new experiences and ideas and therefore less open to actually doing something new. While that disgust may seem irrational, the behavioral immune system is simply reacting to the best information available in an attempt to preserve a person’s health.

The behavioral immune system can even affect our sexuality. Researchers learned that when people were confronted with the idea of contracting a sexually transmitted disease, they were “disgusted” by the idea and altered their behavior accordingly. Women, especially, were prone to having fewer sexual partners and practicing safe sex after receiving an STD warning, potentially preserving their health and fertility in the process.

“Disgust is an important tool, to the extent that it protects us against getting sick,” says Daniel Kelly, PhD, a professor of philosophy at Purdue University and author of Yuck! The Nature and Moral Significance of Disgust. “It’s a first layer of defense against getting infected by parasites which may give us health problems down the road.”

If you think this is gross, then GOOD. (Photo: Corbis/Radius)

Some health-related forms of disgust are even similar across cultures. Kelly points to related research that shows people universally have a knee-jerk disgust response to viewing a photo of a person sweating and coughing or who has open sores.

But psychiatrist David M. Reiss, MD, stresses that our feelings of disgust aren’t foolproof: “We may feel disgusted by some situations and foods that actually are safe, and there are situations and toxins that do not trigger disgust.” So, while you may feel disgusted by the idea of eating broccoli, there’s really no biological reason why you should.

Related: 7 Things You Didn’t Realize You Just Put In Your Mouth

Instead of viewing feelings of disgust as an end-all, be-all decision-maker, Reiss tells Yahoo Health that they should be used as a warning to stop, check what is going on, and, if it’s safe, proceed as usual.

While Kelly agrees that disgust is a valuable warning sign, he says it’s often unreliable when it’s not linked to health, such as views on politics or moral issues. “Disgust should be seen as ‘trustworthy until proven guilty’ for illness,” he says. “However, it shouldn’t be trusted as a moral barometer.”

So, the next time you feel disgusted by the milk that’s been sitting your fridge for a month, you can thank your behavioral immune system for keeping you safe.

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