Dreaming contains abundant references from recent dreamer’s own life, following a surprising 7 day U-shaped timescale (most recent and most old memories in the 7-day period)

Eichenlaub JB., Cash S.S., Blagrove M. (2017) Daily Life Experiences in Dreams and Sleep-Dependent Memory Consolidation. In: Axmacher N., Rasch B. (eds) Cognitive Neuroscience of Memory Consolidation. Studies in Neuroscience, Psychology and Behavioral Economics. Springer, https://doi.org/10.1007/978-3-319-45066-7_10

Abstract: Memories constitute much of the source material for our dreams. Although waking life events are not faithfully replayed in dreams, dream content arises from recent daily experiences. Numerous empirical studies and theoretical accounts highlight the key function of sleep in the consolidation of newly learned memories, raising the question how reference to waking memories in dreams relates to ongoing memory-related processes that take place during sleep. This review attempts to present first the current knowledge of the incorporation of waking memories in dreams by highlighting three main features of this phenomenon i.e. (1) dreaming contains abundant references from recent dreamer’s own life, (2) the wake-dream relation can follow a surprising 7 day U-shaped timescale and (3) salient/intense waking events are more easily incorporated than indistinct/less-intense waking events. Second, this review attempts to discuss the relationship between this phenomenon and the memory-related processes that take place during sleep. The features of the incorporation of waking memories in dreams are in line with some characteristics of the memory processing hypothesized to take place during sleep, suggesting that dreaming might reflect this memory processing. However, substantial limitations and alternative hypotheses must be regarded and addressed in future studies to clarify the link between dream content and sleep-dependent memory consolidation.