Spit, Disgust, and Parasite Stress Theory: A Message Experiment

Public health interventions targeting coughing and spitting during the Tuberculosis and 1918 flu epidemics were largely successful. Specifically, public health officials' messaging framed the behavior of spitting as repulsive and endangering to others, prompting an elicitation of disgust. Anti-spitting campaigns - messaging that focuses on the threat of spit or sputum - have long been common during pandemics and manifested once again to combat the spread of COVID-19. Yet, few scholars have theorized if and how anti-spitting campaigns function to change behavior. One possibility is parasite stress theory, which posits that human behavior is driven by a desire to avoid pathogenic threats like spit. The application of these types of disgust appeals in public health messaging remains understudied and warrants exploration. To test the applicability of the parasite stress theory, our message experiment with US adults (N = 488) examined reactions to anti-spit messages that varied in visual disgust (low and high). For more highly educated respondents, the high disgust appeal directly decreased spitting intentions, and this relationship was stronger for individuals with higher levels of pathogen and moral disgust. Given the importance of public messaging during pandemics, future research should continue to examine the efficacy and theoretical underpinnings of specific disgust appeals.