Influence of sleep and nap habituality on mnemonic discrimination in early childhood: An online study.

Naps protect memories in early childhood. However, critical to episodic memory is the ability to discriminate between similar items, which requires precise memory for details to accurately reject lures. The goal of the present study was to disentangle the role of sleep for general item memory and memory for precise details in 3-5-year-old children, a critical age for development of episodic memory. We used an online child-friendly version of the mnemonic similarity task to examine the roles of napping and overnight sleep on mnemonic discrimination in habitually napping and non-habitually napping children ranging in age from 3;1 years to 5;11 years. In habitual nappers, mnemonic discrimination decreased following a nap but not a similar period awake, suggesting naps promoted generalization of memory representations. Mnemonic discrimination improved following overnight sleep, suggesting overnight sleep promoted memory precision. In non-habitual nappers, mnemonic discrimination did not change following nap or wake conditions. These results suggest that habitual nappers may require overnight sleep to support memory for details while non-nappers may have sufficiently mature brains to support precision memory without sleep.