Creeped out by holes? Psychologists reveal fascinating origin of trypophobia

Fear of holes
CC BY 2.0 Wikimedia Commons

Many people report an aversion to clusters of holes; a new study suggests a very smart evolutionary basis for the discomfort.

Does honeycomb make you shudder, do open pomegranates make your skin crawl, do the lotus pods above send your heart racing, and not in a good way? If so, don’t worry; you are not alone. Although an aversion to holes, commonly known as trypophobia, is not recognized in the American Psychiatric Association's Diagnostic and Statistical Manuel of Mental Disorders (DSM), many people legitimately get the skeevies from irregular clusters of holes.

"Some people are so intensely bothered by the sight of these objects that they can't stand to be around them," says Stella Lourenco, a psychologist at Emory University. "The phenomenon, which likely has an evolutionary basis, may be more common than we realize."

Interestingly, Lourenco and a team of researchers recently conducted a study on the phenomenon, and found that the “fear” of holes is likely linked to a physiological response more in line with disgust than fear.

Earlier research has suggested that the aversion is due to the offensive patterns’ similarities to evolutionarily threatening animals, like snakes or spiders.

"We're an incredibly visual species," says Vladislav Ayzenberg, a graduate student in the Lourenco lab and lead author of the Emory study. "Low-level visual properties can convey a lot of meaningful information. These visual cues allow us to make immediate inferences -- whether we see part of a snake in the grass or a whole snake -- and react quickly to potential danger."

It comes as little surprise that viewing images of threatening animals can trigger the fight-or-flight response, a fear reaction linked to the sympathetic nervous system. Even if we may not notice, tests confirm increases in heart and breathing rates and dilated pupils. But would the same response be true when viewing images of a bunch of holes? Would the sight of aerated chocolate inspire a similar effect to that of a snake?

To explore this question, the researchers used eye-tracking technology to measure changes in pupil size before showing the study participants images of hole clusters, threatening animals and neutral images.

More so than the obviously threatening and neutral images, the holes made the pupils of the participants constrict more, a response that is linked to the parasympathetic nervous system and feelings of disgust, rather than the sympathetic nervous system and feelings of fear.

"On the surface, images of threatening animals and clusters of holes both elicit an aversive reaction," Ayzenberg says. "Our findings, however, suggest that the physiological underpinnings for these reactions are different, even though the general aversion may be rooted in shared visual-spectral properties."

So where a fight-or-flight response is cuing the body to prepare for action, the parasympathetic response slows heart rate and breathing and constricts the pupils.

"These visual cues signal the body to be cautious, while also closing off the body, as if to limit its exposure to something that could be harmful," Ayzenberg says. The thinking is that clusters of holes may be “evolutionarily indicative of contamination and disease -- visual cues for rotten or moldy food or skin marred by an infection.”

Further, the study subjects were students who did not report having an aversion to holes in the first place, suggesting that the reactions are pretty deep-seated. "The fact that we found effects in this population suggests a quite primitive and pervasive visual mechanism underlying an aversion to holes," Lourenco says.

It’s fascinating that no matter how advanced humans become, no matter how detached from the natural world we are getting, we are hard-wired to respond to nature and its processes, even when we don’t know it. While the uninitiated might find an aversion to a lotus pod more neurotic than anything else, the body is just doing what it thinks it needs to do to stay safe in the world, whether it’s from snakes and spiders or moldy food.

The study, "Pupillometry reveals the physiological underpinnings of the aversion to holes," was published in the journal, PeerJ.

Tags: Nature | Wellness

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