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.
Highlights
Sleep facilitates consolidation of declarative memory [1] such that recall of previously acquired materials is better after sleep than after wakefulness
Experiment 1: nocturnal sleep Participants were better at learning related than unrelated word pairs (Relatedness: F1,58 = 191.30, P,0.001)
Learning was at different times of day, the sleep and the wake groups showed similar learning performance (Group: F1,58 = 0.38, P = 0.54; Relatedness6Group interaction: F1,58 = 0.43, P = 0.51; Table 1)
Summary
Sleep facilitates consolidation of declarative memory [1] such that recall of previously acquired materials is better after sleep than after wakefulness. Besides the difference in circadian phase, nocturnal sleep and daytime naps differ in multiple important aspects, such as total sleep time, the amount of sleep spindle-rich stage 2 sleep, slow wave sleep (SWS), and rapid eye movement (REM) sleep. These differences might contribute to differential facilitative effects of nocturnal sleep and daytime napping on declarative memory consolidation [6]. In a study which directly tested the moderating effects of semantic relatedness, nocturnal sleep only abolished the forgetting of unrelated word pairs observed over wakefulness [3] These differential effects have not been investigated for daytime naps. We compared whether nocturnal sleep and daytime napping benefited related and unrelated materials to different extents
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
