Department of Psychology, School of Social Sciences, University of Mannheim.
Psychol Bull. 2021 Dec;147(12):1309-1353. doi: 10.1037/bul0000350.
People recall more information after sleep than after an equally long period of wakefulness. This sleep benefit in episodic memory has been documented in almost a century of research. However, an integrative review of hypothesized underlying processes, a comprehensive quantification of the benefit, and a systematic investigation of potential moderators has been missing so far. Here, we address these issues by analyzing 823 effect sizes from 271 independent samples that were reported in 177 articles published between 1967 and 2019. Using multilevel metaregressions with robust variance estimates, we found a moderate overall sleep benefit in episodic memory (g = 0.44). Moderator analyses revealed four important findings: First, the sleep benefit is larger when stimuli are studied multiple times instead of just once. Second, for word materials, the effect size depends on the retrieval procedure: It is largest in free recall, followed by cued recall and recognition tasks. Third, the sleep benefit is stronger in pre-post difference measures of retention than in delayed memory tests. Fourth, sleep benefits are larger for natural sleep and nighttime naps than for alternative sleep study designs (e.g., slow-wave sleep; SWS-deprived sleep, daytime naps). Although there was no obvious evidence for selective reporting, it is a potential threat to the validity of the results. When accounting for selective reporting bias, the overall effect of sleep on episodic memory is reduced but still significant (g = 0.28). We argue that our results support an integrative, multicausal theoretical account of sleep-induced episodic memory benefits and provide guidance to increase their replicability. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
人们在睡眠后比在同等长度的清醒后能回忆更多的信息。这种情景记忆的睡眠益处已经在近一个世纪的研究中得到证实。然而，目前还缺乏对假设的潜在过程的综合分析、对益处的全面量化以及对潜在调节因素的系统研究。在这里，我们通过分析 1967 年至 2019 年间发表的 177 篇文章中的 271 个独立样本的 823 个效应量来解决这些问题。使用具有稳健方差估计的多层次元回归，我们发现情景记忆中的睡眠益处具有中等程度的总体效应（g = 0.44）。调节分析揭示了四个重要发现：首先，当刺激被多次学习而不是仅一次学习时，睡眠的益处更大。其次，对于单词材料，效应大小取决于检索过程：在自由回忆中最大，其次是线索回忆和识别任务。第三，在保留的前后差异测量中，睡眠益处大于延迟记忆测试。第四，自然睡眠和夜间小睡比替代睡眠研究设计（例如，慢波睡眠；剥夺慢波睡眠的睡眠，白天小睡）的睡眠益处更大。尽管没有明显的选择性报告证据，但这是对结果有效性的潜在威胁。当考虑选择性报告偏差时，睡眠对情景记忆的整体影响会降低，但仍然显著（g = 0.28）。我们认为，我们的结果支持睡眠诱导情景记忆益处的综合多因果理论解释，并为提高其可重复性提供指导。（PsycInfo 数据库记录（c）2022 APA，保留所有权利）。
