The viruses and bacteria that cause infectious diseases cripple well-being, batter economies, and kill millions annually. These negative consequences can be drastically reduced via nonpharmaceutical interventions (NPIs) – behaviors that reduce the spread of pathogens. A wealth of recent theoretical and empirical work has illuminated how and why disgust intuitively motivates some NPIs, such as avoiding bodily wastes and spoiled foods. However, disgust does little to inhibit transmission via aerosols, respiratory droplets, and fomites – key pathways for the respiratory pathogens that circulate seasonally, have caused recent pandemics, and will cause the pandemics of the future. Hence, even with advances in our understanding of disgust, the psychological underpinnings of the less-intuitive NPIs that inhibit respiratory pathogens – such as handwashing, barriers to respiratory droplets and aerosols, and self-isolation while infectious – remain mysterious. This project addresses the urgent need to better understand these NPIs using theory and methods that cut across social psychology, evolutionary psychology, health psychology, and behavioral genetics. First, it catalogs and explains cross-cultural differences and similarities in NPI practices with an unprecedented survey of 61 nations, and it uses a state-of-the-art approaches to assess the degree to which differences in NPIs within societies emerge from genetic versus environmental factors. Second, it uses experimental methods to test the roles of folk theories of immunity, moralization, and conflicts between individual and collective interests on NPI practices. Third, it develops novel, theory-based interventions for increasing handwashing and voluntary quarantining while sick and uses assessments of soap use and social contacts to evaluate those interventions. By providing groundbreaking data, theory development, and informing empirically-supported interventions, this project will arm science and society with critical new knowledge in our battle against infectious disease.
