Can pupillometry dissociate fear and disgust? Trypophobia as a test case. Open Access

Hickey, Meghan Rose (2016)

Permanent URL:


Anxiety in response to objects with a cluster of holes has come to be known as trypophobia. Recent research suggests that such objects share low-level visual properties with evolutionarily threatening stimuli, namely snakes and spiders (Cole & Wilkins, 2013). The current consensus is that, like snakes and spiders, the discomfort associated with holes is rooted in fear. However, self-reports from individuals with trypophobia suggest that this anxiety may instead reflect a disgust reaction. Yet, fear and disgust are difficult to disambiguate behaviorally because both involve an avoidance response (Woody & Teachman, 2000). In the current study, we used pupillometry to test whether trypophobia is rooted in fear or disgust. We predicted that if trypophobic stimuli elicited fear, then they should invoke a sympathetic response, which is associated with pupil dilation; alternatively, if trypophobic stimuli elicited disgust, then they should invoke a parasympathetic response, which is associated with pupil constriction (Granholm & Steinhauer, 2004). To dissociate fear and disgust, in a first experiment participants passively viewed a slideshow of trypophobic, neutral, and threatening images. Next to control for the effect of spatial frequency, in a second experiment participants viewed a slide show of trypophobic images, threatening images, and images with low-level visual details similar to holes. Participants also completed emotional questionnaires and rated each of the images on fear, disgust, anxiety, and arousal to explore the connection between subjective and physiological responses to these stimuli. Pupillary responses across the image categories were compared for each experiment. In experiments 1 and 2, we found that holes elicited significantly more pupil constriction than threatening images, suggesting that the two are dissociable and trypophobia may be rooted in disgust. However, experiment 2 showed that the pupil responses to holes were not different from the low-level visual controls, suggesting that the difference between threat and holes is due to spatial frequency, not emotion. Lastly, correlations between image ratings and emotional questionnaires showed much overlap in the subjective reports of fear and disgust in the threatening and hole categories, suggesting that perhaps these anxiety responses are rooted in a combination of fear and disgust.

Table of Contents

Introduction. 1

Method of Experiment 1. 6

Participants. 6

Measures and Materials. 6

Stimulus presentation and Apparatus. 6

Procedure. 7

Results. 8

Pupil Data Reduction. 8

Analysis of Stimulus Type. 8

Discussion. 9

Method of Experiment 2. 10

Participants. 10

Measures and Materials. 10

Stimulus presentation and Apparatus. 10

Trypophobia Questionnaire (TQ). 11

Snake Questionnaire (SNAQ). 11

Fear of Spiders Questionnaire (FSQ). 12

Questionnaire for the Assessment of

Disgust Sensitivity (QADS). 12

Spielberger's State-Trait Anxiety Inventory (STAI). 12

Stimulus Ratings. 13

Procedure. 13

Results. 13

Rating and Questionnaire Responses. 13

Pupil Data Reduction. 14

Analysis of Stimulus Type. 15

Discussion. 16

General Discussion. 17

References. 21

Figure 1. 26

Figure 2. 27

Figure 3. 28

Table 1. 29

About this Honors Thesis

Rights statement
  • Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.
  • English
Research Field
Committee Chair / Thesis Advisor
Committee Members
Last modified

Primary PDF

Supplemental Files