Sleep as a Window Into Early Neural Development: Shifts in Sleep-Dependent Learning Effects Across Early Childhood

Sleep is an important physiological state for children and adults to consolidate and generalize new learning. In this article, we review research on sleep-dependent memory consolidation and generalization in infants and preschool children, and place the findings in the context of the development of the neural systems underlying memory (the hippocampus and its connections to the cortex). Based on the extended trajectory of hippocampal development, transitions in the nature of sleep-dependent learning are expected. The studies we review show that the nature of sleep-dependent learning changes across early childhood, with sleep facilitating generalization in infants but enhancing precise memory in children 18-24 months and older. Looking ahead, studies on sleep-dependent learning in infants and young children must consider these transitions in early brain development.