A recent study published in PeerJ revealed that Trypophobia, or "fear of holes," is more of a physiological issue associated with disgust rather than fear. Trypophobia has not been recognized in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM).
Despite this, many people do feel an aversion towards clusters of holes, like those of a honeycomb or a lotus seed pod. Even aerated chocolates freak out those who are suffering from trypophobia.
Stella Lourenco, a psychologist at Emory University who conducted the study said that there are a few people who are so affected by the sight of these objects that they choose not to be around them. Moreover, this is a common phenomenon and not something unheard of.
Previous studies on the same linked trypophobic reactions to the visual spectral properties of snakes and spiders that seem to have same clusters of holes. The similar pattern of holes is also seen on a spider's dark legs against a dark background.
According to Vladislav Ayzenberg, lead author of the PeerJ study and a graduate student in the Lourenco Lab said that low-level visual properties can reveal a lot of information thus allowing one to make immediate inferences.
"Whether we see part of a snake in the grass or a whole snake — we react quickly to potential danger," he added.
The study shows that showing someone pictures of threatening animals usually elicits fear among viewers who have a sympathetic nervous system. Palpitation increases and pupils dilate in case of such viewers. This hyperarousal to danger is also known as the fight-or-flight response. Researchers wanted to know whether the same physiological response occurs in case of seeing images of clusters of holes.
Eye-tracking technology was used to detect dilation of pupils to differentiate the responses of the images of hole clusters, images of threatening animals as well as their response to neutral images.
Images of holes narrowed down the pupils than when showed the images of snakes and spiders. Constriction of pupils is usually associated with the feeling of disgust or parasympathetic nervous system.
Ayzenberg said that general aversion towards these images might come from the shared visual spectral properties but the physiological factors might be completely different.
During a parasympathetic response, the body reacts in a different manner. Heart rate slows down and pupils become narrow. These signals the body to be cautious. The authors further state that the clusters of holes might remind some of rotten food or some sort of skin infection that has completely distorted the skin surface. This gives birth to the feeling of disgust. Scientists, since the time of Darwin, linked feelings of fear and disgust. The present study states that the two feelings can overlap.
The subjects used for this experiment were mostly college students who did not report having trypophobia. "The fact that we found effects in this population suggests a quite primitive and pervasive visual mechanism underlying an aversion to holes," said Lourenco.