Ronald Thomas

Date of Graduation


Document Type


Degree Type



Eberly College of Arts and Sciences



Committee Chair

Natalie Shook

Committee Co-Chair

Amy Gentzler

Committee Member

Julie Hicks-Patrick


The Behavioral Immune System (BIS) is a set of psychological processes that evolved to protect individuals from harmful contaminants and pathogens in the environment (Miller & Maner, 2011; Schaller & Duncan, 2007; Tybur, Lieberman, Kurzban, & DeScioli, 2013). The primary mechanism through which the BIS functions is the emotion of disgust, which causes negative physical and affective reactions that encourage avoidance behavior and serve as a deterrent from approaching potentially harmful stimuli (Schaller & Duncan, 2007). Consequently, disgust is proposed to serve a disease-avoidance mechanism. However, relatively little research has empirically tested the link between disgust and general behavioral avoidance tendencies in the BIS literature. The purpose of this research was to directly test the association between disgust and general avoidance tendencies. The first study was correlational to demonstrate the association between trait levels of disgust sensitivity and avoidance tendencies. Participants completed self-report measures of disgust sensitivity and approach-avoidance tendencies, as well as a performance-based measure of approach-avoidance. Disgust sensitivity was positively correlated with avoidance as assessed by a self-report measure (i.e., the Behavioral Inhibition Scale; Carver & White, 1994) and negatively correlated with the approach of positive, but not negative, stimuli in the performance-based task. In the second study, a disgust induction (i.e., consumption of disgusting flavored jellybeans) was compared to a control condition (i.e., consumption of normally flavored jellybeans) in order to test the causal direction of the relation between disgust and avoidance. However, the induction could not be evaluated on whether disgust was induced. Although the groups acknowledged a difference in taste, there were no differences between the groups in self-reported feelings of disgust, although they differed on approach-avoidance tendencies in BeanFest. The data from Study 2 also replicated the correlational findings in Study 1. Disgust sensitivity was negatively correlated with the approach of positive stimuli in the performance-based task and was positively associated with self-reported avoidance. Across both studies, a consistent pattern emerged; people who were more sensitive to disgust exhibited more general avoidance tendencies. These findings have broad implications for behavioral tendencies across social domains. Those who are higher in disgust sensitivity tend to endorse more cautious and avoidant behavior, not just relative to clearly dangerous stimuli, such as phobias and other overt risks, but to general situations and events unrelated to disease.