Children's sleepiness facilitates the effect of vicarious learning on the development of fear.

A substantial body of research demonstrates the importance of sleep for emotional processing and learning as well as the association between sleep problems and heightened anxiety. However, there is currently no research exploring the impact of sleepiness on vicariously learned fear responses. Experiment 1 (N = 38) first demonstrated no effect of trait or state sleepiness on children's (7-11 years of age) subjective ratings of fear. Experiment 2 (N = 42) and Experiment 3 (N = 46) used an established vicarious learning paradigm to demonstrate that trait sleepiness facilitated vicariously acquired avoidance preferences for animals paired with fearful faces (fear-paired animals), whereas state sleepiness facilitated children's fear cognitions and attentional bias toward fear-paired animals. This study is the first to demonstrate the role of state and trait sleepiness in moderating vicarious fear learning in children.