Who's afraid of the tiny holes? If you have an aversion to Aero bars, you may have trypophobia

If the photo of the seedhead of a lotus flower makes your skin crawl, you may well have a phobia about holes.

Researchers have discovered that a substantial minority of Britons suffer from trypophobia, the largely unstudied fear of clusters of tiny holes. The sight of these small, irregularly or asymmetrically placed holes can make people sick, itch, shake and even cry, according to the results of the first academic study into the phenomenon.

Although the phobia is thought to be a relic of an evolutionary survival mechanism that associates such patterns with dangerous animals, the researchers noted that some people have an aversion to obviously innocuous holes – such as those formed by soap bubbles or found in aerated chocolate, like Aero bars.

"It is quite extraordinary that images of something as innocuous as the bubbles in a bar of chocolate can bring about this level of aversion," said psychologists Dr Geoff Cole and Professor Arnold Wilkins of Essex University, whose interest was sparked when a colleague reported having the phobia.

"We have found that significant numbers of people are affected, and that others, who would not be classed as having a phobia, have a dislike of those same images. That supports our theory that it is an evolutionary defence mechanism. For many people trypophobia affects their everyday lives and can be quite debilitating."

In the study, researchers carried out a number of experiments with different images to estimate the prevalence of trypophobia. They exposed 300 men and women aged 18 to 55 to an image of the seedhead of the lotus flower. It was chosen because it was found to be the most often reported trigger for the phobia.

Results show that 18 per cent of the women and 11 per cent of the men had an aversion to the image; they found it uncomfortable or repulsive.

The researchers also examined images of potentially dangerous animals and showed that they too could be trypophobic. The blue-ringed octopus, box jellyfish, the Brazilian wandering spider, death stalker scorpion, inland Taipan snake, king cobra, marbled cone snail, poison dart frog, puffer fish and the stone fish all possess a pattern or body shape similar to that in the trypophobic images.

The researchers suggest that during evolution, specific patterns became a rapid identifying feature for danger, in the form of poisonous animals. While many people feel uncomfortable looking at these images, those with a phobia have an exaggerated response. "We argue that trypophobia arises because the images and objects share a simple visual property with potentially dangerous objects," the researchers say.

"We have found that images responsible for a previously undescribed but relatively common form of visual phobia possess a property characteristic of images that are generally uncomfortable to view. Importantly, we have also found that images of animals well known to be dangerous also possess this visual property.

"We therefore suggest that trypophobia arises because the inducing stimuli share a core spectral feature with such organisms. This feature does not reach conscious awareness, but it induces aversion because of the survival value of such aversion."