Children's thinking about asymptomatic carriers of disease.

Prior research has examined children's understanding of disease transmission between people who demonstrate illness symptoms or are labeled as sick (Blacker & LoBue, 2016; DeJesus et al., 2021). The present studies examine North American children's thinking about illness carriers with varying symptoms in terms of the likelihood and severity of disease transmission (Study 1) and moral judgments about disease transmission (Study 2). In Study 1, we tested 6- to 12-year-old children on Zoom (n = 108, 42 % female, 59 % White). Children were introduced to one character that was symptomatic, asymptomatic, or did not have a novel germ ("Germ X") inside them (the carrier). After the carrier interacted with their friend (the recipient), participants were asked if the recipient caught Germ X and how they would feel later. Children rated the recipient as feeling worse if the carrier had Germ X and was symptomatic. In Study 2, we tested 5- to 10-year-olds at a children's museum (n = 96, 53 % female, 54 % White). Here, the carrier was symptomatic or asymptomatic and shared an apple with the recipient, who later became symptomatic or asymptomatic. Children were asked before and after learning about the recipient's symptoms if the interaction was okay. Children provided worse ratings if the carrier felt sick, and adjusted their ratings based on recipient status after the interaction. Across studies, we observed limited age effects. These findings suggest that children consider the severity of illness as part of its transmissibility and by age 5 negatively view interacting while sick.