Masks as a moral symbol: Masks reduce wearers' deviant behavior in China during COVID-19.

Since the outbreak of COVID-19, mask wearing has become a global phenomenon. How do masks influence wearers' behavior in everyday life? We examine the effect of masks on wearers' deviant behavior in China, where mask wearing is mostly a public-health issue rather than a political issue. Drawing on behavioral ethics research, we test two competing hypotheses: (a) masks disinhibit wearers' deviant behavior by increasing their sense of anonymity and (b) masks are a moral symbol that reduces wearers' deviant behavior by heightening their moral awareness. The latter hypothesis was consistently supported by 10 studies (including direct replications) using mixed methods (e.g., traffic camera recording analysis, observational field studies, experiments, and natural field experiment) and different measures of deviant behavior (e.g., running a red light, bike parking in no-parking zones, cheating for money, and deviant behavior in the library). Our research (n = 68,243) is among the first to uncover the psychological and behavioral consequences of mask wearing beyond its health benefits.