The personality trait self-disgust describes the tendency of individuals to appraise themselves as repulsive. This may refer to their own body and personality (‘personal self-disgust’) and/or to their behaviors (‘behavioral selfdisgust’). The current voxel-based morphometry (VBM) study aimed at identifying associations between grey matter volume (GMV) in specific brain regions of the ‘disgust network’ (e.g., insula, prefrontal cortex) and reported self-disgust in a non-clinical sample. VBM data from 59 women (mean age = 24.8 years) with high vs. low scores on a self-disgust questionnaire were compared with each other. Relative to women with low personal self-disgust, women with a higher degree of this trait were characterized by less GMV in the bilateral insula. This difference was independent of depressed mood. The reduced insula volume may be one neural correlate of an undifferentiated, negatively valenced self-concept.

Introduction

According to evolutionary approaches, disgust evolved as a disease avoidance emotion (Davey, 2011). A variety of different stimuli and situations, such as spoiled food, body products, poor hygiene, and illness typically elicits disgust. The common characteristic of these disgust elicitors is that they can transmit pathogens, parasites and other infectious agents. Therefore, disgust motivates behaviors that reduce the risk of contamination, such as avoidance, rejection, grooming, and cleaning. However, disgust reactions are not limited to disease-relevant cues. Disgust can impact on many other areas of life. Disgust influences friend and mate choices, what social groups we reject (concepts of outgroups), political attitudes, moral decisions, as well as social learning (for a review see Kavaliers, Ossenkopp, & Choleris, 2019). Thus, disgust is a motivational system, which is involved in a broad spectrum of avoidance/rejection behaviors. Disgust is typically directed toward stimuli in the external environment but sometimes people show self-directed disgust responses. Self-disgust is defined as the tendency to experience disgust when appraising one’s own personal attributes and behaviors (Overton, Markland, Taggart, Bagshaw, & Simpson, 2008). Overton et al. (2008) were the first ones who developed a questionnaire for the assessment of the personality trait self-disgust. The self-disgust scale (SDS) has a twofactor structure: disgust as it relates to aspects of the self (disgusting self; e.g., “I find myself repulsive”) and disgust as it relates to aspects of one’s behavior (disgusting ways; e.g., ‘The way I behave, makes me despise myself’).