Effects of wakeful rest on memory consolidation: A systematic review and meta-analysis

Individuals spend roughly two-thirds of their day awake, with about half of that time in an offline state. This period may appear unproductive, potentially leading to perceived inefficiency. However, this period appears to be an essential component of our daily lives. Studies have increasingly found that quiet and wakeful rest after learning facilitates the consolidation of newly acquired memories, and enhances memory performance. Few studies quantitatively assessed the overall effect size of wakeful rest on memory consolidation, or examined the potential moderating factors. Therefore, we conducted this meta-analysis, compiled from 37 studies, including a total of 63 experiments that contributed 82 comparisons to this meta-analysis. We used a multilevel random-effects model to reveal a significant effect of wakeful rest on memory consolidation (Hedges's g = 0.448, 95% CI [0.339, 0.557], Z = 8.044, p < .001), and this effect persists even after 7 days (Hedges's g = 0.270, 95% CI [0.024, 0.516], Z = 2.153, p = .031). The effect of wakeful rest was influenced by age, with older adults deriving greater benefits compared with younger adults. Across different outcome measurements, the effect was better reflected by recall than by recognition. Additionally, the duration of wakeful rest, whether the eyes are open or closed, the luminance level, and the body posture do not seem to influence the wakeful rest effect. This meta-analysis offers a deep understanding of the effects of wakeful rest on memory consolidation and provides guidance for the experimental designs of future research in this area.