Evaluating the 'skin disease-avoidance' and 'dangerous animal' frameworks for understanding trypophobia

Trypophobia, skin disease, and the visual discomfort of natural textures

In the last decade, the behavioral sciences have described the phenomenon of trypophobia, which is the discomfort felt by some individuals when viewing images containing clusters of bumps or holes. One evolutionary hypothesis for this phenomenon is that this visual discomfort represents an adaptation which helps organisms avoid skin disease and/or ectoparasites. Even though trypophobic imagery and disease imagery are both examples of visual textures, to date there has been no comparison of the visual discomfort elicited by these two specific kinds of textures within the larger context of the visual comfort elicited by natural texture imagery more generally. In the present study, we administered the Trypophobia Questionnaire (TQ) and recorded the visual comfort ratings elicited by a large set of standard natural texture images, including several trypophobic and skin disease images. In two independent samples, we found that while all observers find skin diseases uncomfortable to view, only those scoring high on the TQ rated trypophobic imagery equally uncomfortable. Comparable effects were observed using both standard ANOVA procedures as well as linear mixed effects modeling. Comparing the ratings of both high-TQ and low-TQ participants to the standard textures, we find remarkably consistent rank-order preferences, with the most unpleasant textures (as rated by both groups) exhibiting qualitative similarities to trypophobic imagery. However, we also find that low-level image statistics which have been previously shown to affect visual comfort are poor predictors of the visual comfort elicited by natural textures, including trypophobic and disease imagery. Our results suggest that a full understanding of the visual comfort elicited by natural textures, including those arising from skin disease, will ultimately depend upon a better understanding of cortical areas specialized for the perception of surface and material properties, and how these visual regions interact with emotional brain areas to evoke appropriate behavioral responses, like disgust.

The social learning account of trypophobia

Trypophobia is the condition in which individuals report a range of negative emotions when viewing clusters of small holes. Since the phenomenon was first described in the peer-reviewed literature a decade ago, 49 papers have appeared together with hundreds of news articles. There has also been much discussion on various Internet forums, including medical and health-related websites. In the present article, we examine the degree to which the phenomenon is caused by a form of social learning, specifically, its ubiquitous social media presence. We also examined its prevalence among the broad population. In Experiment 1 (n = 2,558), we assessed whether younger people and females (i.e., greater social media users) are more sensitive to trypophobic stimuli, as predicted by the social media hypothesis. In Experiment 2 (n = 283), we examined whether sensitivity to trypophobic stimuli and rates of trypophobia is greater in people who are aware of the condition's existence, as opposed to those who have never heard of the phenomenon. In line with the social media theory, results showed that younger people and females are indeed more susceptible to trypophobia. However, 24% of trypophobic individuals have never heard of the condition. Overall, these data suggest that both social learning and non-social learning contribute to trypophobia. We also find that the prevalence of trypophobia is approximately 10%.

Is trypophobia real?

Approximately 10-18% of the adult population experience some form of anxiety when viewing clusters of small holes. 'Trypophobia' has been the subject of much discussion within the peer-reviewed literature, news outlets, health-related websites and social media. However, there is some scepticism surrounding the phenomenon. It is often stated that the condition is not recognised by the American Psychiatric Association, and not listed as a phobia in the DSM-5. It has also been claimed that trypophobia is no more than a particularly successful internet meme. In this editorial, I argue that such criticisms are misplaced. There is, for instance, no list of phobias in the DSM-5; only criteria that determine phobia classification. Using these criteria, as well as personal testimonials, trypophobia is clearly a phobia. Furthermore, the meme hypothesis cannot account for the fact that the phenomenon existed long before the internet.

Pupillary Responses to Dot Patterns on a Human Face Background

Dots on natural backgrounds can elicit significant pupillary constrictions within the entire image phase associated with parasympathetic activation, suggesting disgust rather than fear. Although studies have reported that dots on faces elicit stronger disgust than dots on non-face backgrounds, it remains unclear whether dots on a face elicit stronger pupil constrictions than non-face backgrounds. Pupillometry was used while viewing dots on faces and compared with luminance- and spatial frequency-controlled images (dots on phase-scrambled faces) and luminance-controlled images (face only, phase-scrambled faces). Relative pupillary constrictions were elicited when dots were placed on faces and phase-scrambled faces; however, the response to dots on faces did not differ significantly from that to the control stimuli. Approximately 3-5 s after stimulus onset, pupillary responses to dots on faces recovered to baseline faster than those to dots on phase-scrambled faces with a larger pupil size. The initial pupillary constrictions observed are consistent with those in response to dots on natural backgrounds, suggesting that regardless of the background, dots may stimulate parasympathetic activation and elicit disgust rather than fear. The faster recovery from the pupil constriction and larger pupil size in the later phase may be caused by a dynamic balance between the sympathetic and parasympathetic neuronal activities.