Trypophobia is the fear of clusters of small circular holes or bumps, such as the holes in a sponge. The term has only existed since 2005, when it was coined on an online message board, and has yet to be officially recognised as a type of psychological disorder.

Despite this, increasing numbers of people are convinced they ‘have’ trypophobia. Googling the term throws up over 1million search results – and more and more scientists are beginning to investigate what might be behind it.

In a new study, psychologists at the University of Kent have developed a new theory about why so many of us are creeped out by the sight of tiny holes.

The research, published in the journal Cognition and Emotion, suggests that trypophobia is linked to deep-seated evolutionary anxieties about parasites and infectious diseases, leading to an exaggerated reaction to round shapes.

Psychologists observed that many infectious diseases – from smallpox to measles, rubella to typhus and scarlet fever – cause clusters of circles on the skin.

In addition, several ectoparasites, such as scabies, tics and botfly, lead to circular clusters on the skin.

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Led by Tom Kupfer of the University’s School of Psychology, the team of researchers recruited around 600 people to take part in their study.

More than 300 participants were people from trypophobia support groups, while around 300 were university students who didn’t have the phobia.

Both groups were asked to look at 16 images, all of which depicted real objects bearing cluster patterns.

Half of the photos showed clusters related to diseased body parts, such as circular rash marks on a chest or smallpox scars on a hand. (Feeling queasy yet?)

The other eight pictures showed cluster patterns that weren’t related to disease – or, indeed, to anything obviously negative or unsettling. Objects featured in these images included drilled holes in a brick wall, a lotus flower seed pod.

As you might imagine, both groups of participants found the disease-related photos unpleasant to look at. However, when it came to the more neutral cluster images, their responses were very different.

The university students didn’t have any negative reaction to the pictures of disease-unrelated circular patterns. The individuals with trypophobia, in contrast, found it extremely unpleasant to look at the images – even those showing objects as innocuous as the bubbles in a cup of coffee.

Psychologists concluded that people with trypophobia experience an overgeneralised response to clusters, whereby their aversion to all grouped circular patterns is as strong as most people’s dislike of disease symptoms.

Previous research has shown that the emotion disgust exists to help us avoid sources of potential infection. With this in mind, psychologists predicted that unlike many phobias involving intense but rational fears (such as the phobia of snakes, heights or dogs), people with trypophobia would generally experience intense disgust.

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This prediction was proved correct when they asked participants with trypophobia to describe how they felt when they looked at images of lots of little holes. Most trypophobics said that they experienced disgust or disgust-related feelings, such as nausea or the urge to throw up, even towards images that had nothing to do with disease (such as the holes in a sponge). Only a tiny proportion of individuals said that they felt fear.

As well as disgust, people with trypophobia frequently reported feelings like skin itching, skin crawling or even the sensation of “bugs infesting the skin”. This response indicates that people with trypophobia react to cluster images as though they’re warnings of ectoparasites, even causing some to feel as if they are infested.

This is not the first study that has attributed trypophobia to a misplaced evolutionary response. In 2013, scientists at the University of Essex in 2013 suggested that sufferers unconsciously associated circular holes with the patterns on potentially dangerous animals, such as the venomous blue-ringed octopus.

However, it’s important to remember that feeling a bit grossed out by something isn’t the same as having a full-blown phobia – and there may be an element of emotional contagion involved. As Jennifer Abusi observes in Popular Science, it’s not unusual for people to say that they didn’t realise they were trypophobic until they looked at ‘triggering’ photos and read about the phenomenon online.

“It’s not unusual to laugh harder at a funny movie if others around you are laughing,” explains Martin Antony, a psychologist at Ryerson University in Toronto and author of The Anti-Anxiety Workbook. “In the same way, we may be more likely to experience fear in a particular moment if others around us are fearful.”

Images: iStock, George Marks