PROJECT SUMMARY Sleep protects and enhances memory in young adults: performance changes on a range of tasks are greater following an interval with sleep relative to changes over an interval spent awake. In young adults, a mid-day nap is sufficient for gaining these performance benefits. Unlike adults, mid-day naps are routine for young children. As such, the nap opportunity in preschools may serve as a target for intervention in children with learning impairments and reduced overnight sleep opportunities. However, whether naps confer a particular benefit to learning and performance of young children is unknown. The specific objective of the proposed research is to examine whether naps contribute to immediate and delayed benefits on multiple forms of learning in young children (3-5 yrs). By probing recall prior to and following mid-day nap or wake intervals, the overarching hypothesis is that recent memories are actively processed (as opposed to passively protected) by a nap, conferring immediate or delayed (24-hrs) benefits on declarative (Aim 1), procedural (Aim 2), and emotional (Aim 3) memories. In two conditions, children will either be nap-promoted or wake-promoted mid- day. Subsequently, performance will be reassessed that day as well as the following day. The specific hypotheses examined are: a) mid-day naps benefit learning; b) naps yield stronger memories at 24-hrs; c) performance benefits are due to an active role of sleep as indicated by a relationship between sleep physiology and behavior. This work is innovative in that it presents a novel application of an accepted theoretical construct. Moreover, these results are expected to shift the current practices regarding naps in preschools to a practice of nap-promotion and better regard for the length of the nap opportunity. The translational significance may be seen in new policies regarding in-class nap opportunities and pediatric nap guidelines for preschool children. The theoretical significance is that these outcomes will drive an entirely new research dimension for educational sciences (sleep as a novel target to enhance learning) and spur further developmental studies on the influence and underpinnings of sleep-dependent cognitive and neural processes.