The fear of holes -- called trypophobia -- may have an evolutionary basis, according to a new study in the journal Psychological Science.
For people who have trypophobia, seeing certain clusters of holes can trigger feelings of fear and uneasiness. University of Essex researchers looked at 76 different photos that trigger trypophobia and compared them with 76 photos of things with holes that aren't linked with trypophobia to try to tease apart any differences between the two. What they found was a potential link between trypophobia and certain poisonous animals.
In other words, some poisonous animals -- such as the king cobra snake or the blue-ringed octopus -- have visual features similar to those of other more innocuous objects that might trigger trypophobia.
"We performed a spectral analysis on a variety of images that induce trypophobia and found that the stimuli had a spectral composition typically associated with uncomfortable visual images, namely, high-contrast energy at midrange spatial frequencies," researchers wrote in the study. "Critically, we found that a range of potentially dangerous animals also possess this spectral characteristic."
The blue-ringed octopus in particular tipped the researchers off to this potential link, since one of the men they talked to for the study had his phobia triggered in response to seeing the animal.
"We think that everyone has trypophobic tendencies even though they may not be aware of it," study researcher Geoff Cole, a psychological scientist at the university, said in a statement. "We found that people who don’t have the phobia still rate trypophobic images as less comfortable to look at than other images."