Have you ever seen something so gross that it makes your stomach churn, and you have to stop yourself from throwing up? Well, apparently that’s your body’s way of protecting you. Scientists say disgust is a survival instinct. ​

Disgust, wrote Charles Darwin in the 1860s, is inborn and involuntary, and it evolved to prevent our ancestors from eating spoiled food that might kill them.

Joshua Ackerman is not one to shy away from disgusting things. In fact, he's an expert when it comes to disgust, having researched the emotion extensively. When we reached out to Ackerman, the professor of psychology from the University of Michigan was more than happy to answer some questions for us.

"Disgust is an emotion that evolved to help us manage the threat of harm from infection and toxic substances," Ackerman told Bored Panda. "We often feel disgust in response to threat cues like bodily fluids, symptoms of illness like coughs and pus, rotting foods, and waste products. Disgust creates a strong aversion to cues and drives us to avoid interacting with them in ways that might spread germs or otherwise lead us to get sick. In strong cases, it can help us expel substances we've ingested, for example through vomiting."

While some of us prefer to steer clear of anything that might gross us out, others get a kick out of watching disturbing videos or looking at disgusting photos like the ones in this compilation. Ackerman tells Bored Panda there's a name for this...

"The concept of 'benign masochism' refers to situations where people prefer typically negative experiences," he says. "For people like this, they don't tend to like the full experience of disgust. Instead, they get enjoyment from the physiological reactions created in the body and mind when they feel 'just enough disgust,' which is more likely to happen when looking at pictures or watching videos than when actually touching or eating gross things."

We asked Ackerman if it's possible for someone to train themselves to be less disgusted. He explained that disgust reactions are acquired, or learned. Through a learning process, you can train down these responses, he says.

"Whether this is a good activity or not depends on your goal. If you work in a field where you regularly encounter disgust cues (such as sanitation or a hospital), feeling lower levels of disgust can be helpful for getting your job done," said the expert.

"In many cases, people also will naturally become desensitized over time in such situations, even if they aren't intentionally trying to feel less disgust. However, if you train yourself to feel less disgust in a wide variety of situations, this can be counterproductive. Disgust works to help people avoid disease-causing germs and toxins. Feeling less disgust can potentially lead people to stop avoiding these dangers and thus to get sick more often."

When researchers looked into the link between disgust and COVID, they found that those more prone to feelings of disgust fared better during the pandemic. Ackerman explains that this is because disgust is effective at lessening the probability of illness.

"If people experience disgust to true signs of danger, like someone sick with a contagious illness such as COVID, this can motivate those people to avoid social interactions and other encounters likely to spread germs," he explained.

"Compared to many respiratory diseases, COVID is a little tricky though, as many strains were often accompanied by asymptomatic spread and symptoms less likely to create disgust in others (e.g., fever, feeling terrible). Without cues that elicit disgust, people don't have the same emotional trigger that helps them avoid contagion."

Researchers from the London School of Hygiene and Tropical Medicine compiled a rather wild survey that I, for one, am happy I didn't take part in. They came up with 75 potentially disgusting scenarios and then asked more than 2,500 people to rate their level of disgust for each one.

Not that you asked, but some of the gross examples include ​​finding a chicken fetus when cracking open an egg, learning that a friend tried to have sex with a piece of fruit, hearing about someone eating rabbits and birds that had been left for dead on the road, looking at genital sores, seeing people eat raw fish heads on TV, and finding out a neighbor likes to poop in his backyard.

The study found that most of the things humans find disgusting fall into six categories. Each one is related to how likely they are to possibly transmit disease.

According to a press release, "Of all the scenarios presented, infected wounds producing pus were rated as the most disgusting. The violation of hygiene norms—such as having bad body odour, was also found to be particularly disgusting."

The survey results also showed that there were differences in how men and women reacted to each of the disgusting scenarios. Women rated each and every category more disgusting than men. "This is consistent with the fact that men are known to indulge in riskier behaviour than women, on average," reads the press release, adding that the categories women found most disgusting were risky sexual behavior and animals carrying diseases.

​​"Although we knew the emotion of disgust was good for us, here we've been able to build on that, showing that disgust is structured, recognising and responding to infection threats to protect us," said lead researcher Professor Val Curtis.

Co-author of the paper Micheal de Barra said the results show that people have an intuitive sense of what to avoid in their environment. "Our long coevolution with disease has 'wired in' this intuitive sense of what can cause infection," explained de Barra.

So next time you want to gag when someone coughs in front of you, or you see maggots crawling on rotten meat, ask yourself what your body is trying to tell you. Your feelings of being grossed out might not be so useless after all but rather nature's way of protecting you.

Which of the images on this list gave you the ick? Don't forget to upvote them and feel free to tell us more about what you find most disguting in the comments down below.