One hundred twenty-six adults whose first language was Japanese (83 males, 43 females, mean age 39.72 years, SD = 9.41) participated in this study on April 2015. Age did not differ between the genders [t(124) = .14, p = .89, d = .03]. Participants were recruited using Yahoo! Crowdsourcing, an online labor market similar to Amazon Mechanical Turk, whose validity and reliability for psychometric studies have been confirmed (Buhrmester et al. 2011; Shapiro et al. 2013).
The Trypophobia Questionnaire (TQ; Le et al. 2015), Japanese version (Imaizumi et al. 2016) comprises 17 items with a one-factor structure assessing proneness to emotional (e.g., “Feel aversion, disgust or repulsion”) and somatic responses (e.g., “Have goosebumps”) induced by trypophobic stimuli (e.g., lotus seed pods, honeycombs). Participants rated their agreement with each item on a five-point scale ranging from 1 (“not at all”) to 5 (“extremely”). Responses were summed to produce a score of trypophobia proneness.
The Disgust Scale-Revised (DS-R; Haidt et al. 1994; modified by Olatunji et al. 2007b), Japanese version (Iwasa and Tanaka 2013), comprises 25 items measuring disgust sensitivity in three subscales: Core, Animal Reminder, and Contamination disgust. Participants indicated their agreement with 13 statements on a five-point scale ranging from 0 (“strongly disagree”) to 4 (“strongly agree”), and evaluated how disgusting they would find 12 situations, also on a five-point scale (0 = “not at all disgusting” to 4 = “extremely disgusting”). Although the original version adopted two- and three-point scales, five-point scales were used based on advice from the original authors of the English scale. Subscale scores were calculated by summing item scores.
Emotional and cognitive empathic traits were assessed with the Interpersonal Reactivity Index (IRI; Davis 1980, 1983), Japanese version (Sakurai 1988), which comprises 28 items in four subscales: Perspective Taking, which assessed cognitive empathic traits; and Fantasy, Empathic Concern, and Personal Distress, which assessed emotional empathic traits. Each item was answered using a five-point scale ranging from 0 (“does not describe me well”) to 4 (“describes me very well”). The empathic traits were defined as the summed item scores of each subscale.
We used the 23-item Visual Discomfort Scale (VDS; Conlon et al. 1999) to assess daily experiences of visual discomfort, including abnormal perception and somatic symptoms. Each item was answered using a four-point scale ranging from 0 (“event never occurs”) to 3 (“almost always”). The sum of item scores indicated proneness to visual discomfort.
This survey was administered via the online tool SurveyMonkey (http://www.surveymonkey.com) using participants’ own computers. Initially, potential participants were informed that participation was voluntary and that they could quit any time. Individuals who consented to participate first completed the TQ, then the DS-R, IRI, and VDS in a random order, and reported their gender and age. Finally, participants were thanked and paid 150 Japanese yen (approximately 1.25 US dollars).
We analyzed descriptive statistics and zero-order Pearson correlations for the TQ, DS-R subscales, IRI subscales, and VDS. Next, we checked for gender differences in these scales using two-tailed t tests because females may score higher on disgust sensitivity (Olatunji et al. 2008) and empathic traits (Davis 1980; Mestre et al. 2013) than males. To identify variables predicting trypophobia proneness, we performed stepwise multiple regression analysis with TQ as the dependent variable, and the DS-R subscales, IRI subscales, VDS, and gender as independent variables. All analyses were conducted using SPSS Statistics 20.0 (IBM Corp., Armonk, NY, USA) with the significance level set at p < .05.