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Comparing the effects of nocturnal sleep and daytime napping on declarative memory consolidation

Lo, June C.; Dijk, Derk Jan; Groeger, John A.


June C. Lo

Derk Jan Dijk

John A. Groeger


Marianna Mazza


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.


Lo, J. C., Dijk, D. J., & Groeger, J. A. (2014). Comparing the effects of nocturnal sleep and daytime napping on declarative memory consolidation. PLoS ONE, 9(9), Article e108100.

Journal Article Type Article
Acceptance Date Aug 20, 2014
Online Publication Date Sep 17, 2014
Publication Date Sep 17, 2014
Deposit Date Apr 20, 2016
Publicly Available Date Oct 27, 2022
Journal PLoS ONE
Print ISSN 1932-6203
Electronic ISSN 1932-6203
Publisher Public Library of Science
Peer Reviewed Peer Reviewed
Volume 9
Issue 9
Article Number e108100
Keywords Memory consolidation, Sleep, Napping, Cognition
Public URL
Publisher URL
Additional Information Copy of article first published in: PLoS ONE, 2014, v.9, issue 9.


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Copyright Statement
© 2014 Lo et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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