Emotional Salience of Evolutionary and Modern Disgust-Relevant Threats Measured Through Electrodermal Activity

Background: The study of psychophysiological responses to disgust-evoking stimuli has long been neglected in favour of other emotional stimuli, especially those evoking fear. While the basic cascade of responses to a frightening stimulus is relatively well-understood, psychophysiological responses to disgust-related threats, such as parasites or rotten food, are scarcely studied. Methods: Here, we aimed to assess skin resistance (SR) change as a measure of electrodermal response to visual cues that signal the presence of disgust-relevant threats. To this aim, we recruited 123 participants and presented them with one of the following varieties of disgust-relevant threats: disgust-evoking animals (e.g., parasites, worms), spoiled food, threat of pandemic, or pollution and toxicity. The latter two represented modern threats to test whether also these modern stimuli can initiate immediate automatic reaction. Results: We found significant differences between the categories: Participants responded with the highest probability to disgust-evoking animals (38%) and sneezing (52%), suggesting that only ancestral cues of pathogen disgust trigger automatic physiological response. Moreover, we found significant inter-sexual differences: women exhibited more SR change responses than men, and the amplitude of these responses was overall larger. Finally, we report a weak effect of subjectively perceived disgust intensity on reactivity to threat stimuli. Conclusions: We discuss heterogeneity of disgust-relevant threats, their adequate behavioural responses, and subsequent heterogeneity of respective SR responses. We conclude that large interindividual variability might eclipse systematic differences between participants with high or low sensitivity to disgust, and that subjectively perceived intensity of disgust is only a weak predictor of electrodermal response to its elicitor.