Facial impressions of niceness influence children's interpretations of peers' ambiguous behavior

Children infer personality traits from faces when they are asked explicitly which face appears nice or mean. Less is known about how children use face-trait information implicitly to make behavioral evaluations. We used the Ambiguous Situations Protocol to explore how children use face-trait information to form interpretations of ambiguous situations when the behavior or intention of the target child was unclear. On each trial, children (N = 144, age range = 4-11.95 years; 74 girls, 67 boys, 3 gender not specified; 70% White, 10% other or mixed race, 5% Asian, 4% Black, 1% Indigenous, 9% not specified) viewed a child's face (previously rated high or low in niceness) before seeing the child's face embedded within an ambiguous scene (Scene Task) or hearing a vignette about a misbehavior done by that child (Misbehavior Task). Children described what was happening in each scene and indicated whether each misbehavior was done on purpose or by accident. Children also rated the behavior of each child and indicated whether the child would be a good friend. Facial niceness influenced children's interpretations of ambiguous behavior (Scene Task) by 4 years of age, and ambiguous intentions (Misbehavior Task) by 6 years. Our results suggest that the use of face-trait cues to form interpretations of ambiguous behavior emerges early in childhood, a bias that may lead to differential treatment for peers perceived with a high-nice face versus a low-nice face.