The Contagiousness Bias (with Julia Y. J. Jeong)

We identify the “contagiousness bias,” a self-other discrepancy in judgment, whereby people infected with a contagious disease perceive themselves to be less contagious than a stranger with the same disease. In five studies, we document the contagiousness bias for various diseases (e.g., cold, COVID-19, STIs). We show that this bias occurs because people cope with being sick by downplaying the symptom severity of their own (vs. another person’s) illness. Accordingly, perceptions of symptom severity mediate this effect (Studies 1 and 5) and the contagiousness bias attenuates when people merely imagine being sick (i.e., when there is less of a need to employ coping mechanisms; Study 2). Furthermore, we find that the contagiousness bias persists even in the presence of explicit information about one’s own contagiousness (Study 3) and creates a self-other discrepancy in attitudes toward complying with health recommendations (Studies 1 and 3). Finally, we show that the contagiousness bias is moderated by the extent to which others are included in one’s self-concept (Studies 4 and 5). We discuss the theoretical and practical implications of these findings for management and organizational behavior.