From drug laws to recreational substance use: The adaptationist role of disgust sensitivity

Disgust promotes evolutionary fitness by reducing contact with stimuli that pose pathogenic, sexual, and moral threats. One behavior that may be viewed as a threat to evolutionary fitness is substance use, which is associated with disease transmission, reproductive issues, and engagement in moral transgressions. However, the extent to which individual differences in disgust sensitivity are related to substance use is unclear. Across three studies, associations were examined among sexual, moral, and pathogen disgust sensitivity and beliefs and behaviors regarding substance use. Individuals with higher sexual and moral disgust sensitivity viewed drug laws as more important, endorsed greater punishment for breaking those laws, reported less engagement in substance use, and had lower intentions of engaging in future substance use. Greater sexual disgust was uniquely associated with stronger feelings of obligation to obey drug laws and fewer opportunities to engage in substance use offered by others. Furthermore, associations among sexual disgust, substance use intentions, and self-initiated behavior were partially mediated by beliefs about the harmfulness of substance use. Findings support the adaptationist role of disgust, and suggest that disgust sensitivity is an important individual difference in substance use beliefs and behaviors.