The physiological underpinnings of aversion to images of clusters of holes (new study)

When you look at the photo above, perhaps you see :

1) A delicious-looking much-loved chocolate bar renowned for its unique bubbly texture.


2) A nightmarish and disgusting depiction of tightly clustered holes.

If your reaction leans more towards the latter, it’s possible that you are suffering from trypophobia. Which is (currently being) defined as “an aversion to a cluster of innocuous holes”. Over the past few years, there has been some debate about whether trypophobia really exists, so researchers Vladislav Ayzenberg​, Meghan R. Hickey, and Stella F. Lourenco​ of the Department of Psychology, Emory University, Atlanta, US, decided to perform a set of experiments. The research team showed participants pictures of snakes and spiders, along with possible trypophobiagenic images (plus neutral objects as a control). At the same time they measured the pupil size of the participants  – pupil dilation is (amongst other things) a reliable fear-response indicator.

“Across two experiments, we found greater pupillary constriction to holes than to snakes and spiders, as well as different types of neutral images. Importantly, this effect could not be explained by arousal or low-level visual properties (though more research would be useful to ensure that spatial frequency alone does not account for pupillary responses). These findings are consistent with involvement of the parasympathetic nervous system when viewing images of holes and is suggestive of a disgust, not fear, response to these images. “

Although the results suggest that the “specific emotional response may reflect cognitive appraisal of image content”, there is currently no broadly accepted explanation as to why such a specific response to images of clusters of holes may have evolved in humans.

See: Pupillometry reveals the physiological underpinnings of the aversion to holes in the journal PeerJ 6:e4185, January 4, 2018.

BONUS Assignment [optional] : Suggest more images (other than those used in the study) that might be used to elicit trypophobic responses in future studies.

Note: The picture of the AERO® Milk Bar, which was not used in the study, is provided courtesy of Evan-Amos at Wikipedia