title: Comparing the effects of nocturnal sleep and daytime napping on declarative memory consolidation.
abstract: Nocturnal sleep and daytime napping facilitate memory consolidation for semantically related and unrelated word pairs. We contrasted forgetting of both kinds of materials across a 12-hour interval involving either nocturnal sleep or daytime wakefulness (experiment 1) and a 2-hour interval involving either daytime napping or wakefulness (experiment 2). Beneficial effects of post-learning nocturnal sleep and daytime napping were greater for unrelated word pairs (Cohen's d=0.71 and 0.68) than for related ones (Cohen's d=0.58 and 0.15). While the size of nocturnal sleep and daytime napping effects was similar for unrelated word pairs, for related pairs, the effect of nocturnal sleep was more prominent. Together, these findings suggest that sleep preferentially facilitates offline memory processing of materials that are more susceptible to forgetting.
authors.affiliation: Cognitive Neuroscience Laboratory, Duke-NUS Graduate Medical School, Singapore, Singapore; Surrey Sleep Research Centre, University of Surrey, Guildford, United Kingdom; Department of Psychology, University of Surrey, Guildford, United Kingdom.
authors.forename: June C
authors.initials: JC
authors.lastname: Lo
authors.affiliation: Surrey Sleep Research Centre, University of Surrey, Guildford, United Kingdom.
authors.forename: Derk-Jan
authors.initials: DJ
authors.lastname: Dijk
authors.affiliation: Surrey Sleep Research Centre, University of Surrey, Guildford, United Kingdom; Department of Psychology, University of Surrey, Guildford, United Kingdom; Department of Psychology, University of Hull, Hull, United Kingdom.
authors.forename: John A
authors.initials: JA
authors.lastname: Groeger
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D000069077:Memory Consolidation; D012660:Semantics; D012890:Sleep / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult