How do you feel about this image?
Trypophobia is not currently recognized by the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders as a mental disorder.
However, within forum discussions and social media threads, thousands of people admit to feeling distinct discomfort when they see clusters of holes.
These people might be disturbed by the sight of honeycomb or lotus seed heads (such as those in the image). Some of us even feel queasy in the presence of aerated chocolate.
Researchers led by Stella Lourenco, a psychologist at Emory University in Atlanta, GA, decided to dig deeper into trypophobia and asked why it might occur.
Specifically, the team wanted to get to grips with the physiological and psychological drivers of this rather odd — and currently unofficial — phobia. Their results are published this week in the journal PeerJ.
Though the word "trypophobia" may not be particularly familiar, Lourenco says, "The phenomenon, which likely has an evolutionary basis, may be more common than we realize."
Fear and disgust
Both fear and disgust impart an evolutionary advantage — fear helps us to avoid peckish predators, while disgust steers us away from eating perished plums. These negative emotions are certainly psychological bedfellows, but they're also distinct entities.
Over the years, since Darwin's time, the similarities and differences between fear and disgust have been debated. It is now established that the physiological responses are different: fear activates the sympathetic nervous system, and disgust triggers the parasympathetic nervous system.
The sympathetic nervous system prepares the body for threat or injury by increasing heart rate and contracting muscles. The parasympathetic nervous system controls general body functions at rest, making muscles relax and heart rate decrease.
Repeating patterns and primal fears
The first question to ask is why groups of holes and irregular repeating patterns are frightening to our primal, caveman brains.
Some psychologists believe that the high contrast seen in trypophobia-inducing images is similar to patterns found on some dangerous animals, such as snakes. It has been argued that this similarity could be the driving force behind the negative response.
"We're an incredibly visual species. 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."
Lead study author Vladislav Ayzenberg, graduate student in Lourenco's laboratory
If we spot a snake (or snake-like object) in the grass, it triggers our so-called "fight or flight" response, which is mediated by the sympathetic nervous system and readies our body for imminent danger.
The study was designed to identify whether a trypophobic reaction is triggered by the sympathetic or parasympathetic nervous system. The team wanted to know whether this odd reaction is based on disgust or fear.
Pupillometry — which is an eye-tracking technique that measures pupil size and reactivity — let the scientists glimpse the physiology behind the emotion. Earlier work had shown that a fear response induces an increase in pupil size while, conversely, disgust causes pupil size to decrease.
Delicious or disgusting?
Using this knowledge, the researchers showed participants three sets of images:
- 20 showing threatening animals (spiders and snakes)
- 20 known to trigger a trypophobic reaction
- 20 controls that included pictures of cups, butterflies, and other inoffensive subject matter
The theory goes that if trypophobia is a fear response, a person's pupils should respond in a similar way to both the images of dangerous beasts and lotus seed pods.
If, however, trypophobia is a disgust-based response, the pupils would behave differently between the two experimental image types.
After analysis, it was clear that both the images of dangerous animals and trypophobic patterns triggered a response. However, they were not the same: pictures of snakes and spiders caused an increase in pupil size, whereas images of holes caused the pupils to constrict.
"On the surface," states Ayzenberg, "images of threatening animals and clusters of holes both elicit an aversive reaction. 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."
The researchers conclude that rather than the trypophobia-inducing images mimicking dangerous animals, they might remind our primal brains of rotten or moldy food. This, rather sensibly, triggers a disgusted reaction and an aversion to the images.
Interestingly, the study was carried out on students, none of whom reported having trypophobia. As Lourenco explains, "The fact that we found effects in this population suggests a quite primitive and pervasive visual mechanism underlying an aversion to holes."
More studies will be needed to firm up these findings, but they do add extra weight to the theory that fear and disgust are separate but related emotions. So, if you have trypophobia, remember: you are not afraid of holes, you are disgusted by them.