The dream-lag effect: Selective processing of personally significant events during Rapid Eye Movement sleep, but not during Slow Wave Sleep.
Neurobiology of Learning and Memory July 1, 2015 E Van Rijn, J-B Eichenlaub, P A Lewis et al.
Incorporation of waking-life events into REM sleep dreams is highest on the night after and then 5-7 nights after the events, known as the day-residue and dream-lag effects. In experiment 1 with 44 participants, the dream-lag effect appeared for personally significant events incorporated into REM dreams recalled at home, but not for major daily activities or major concerns. No dream-lag effect was found for slow wave sleep dreams or for REM dreams collected in the lab after earlier SWS awakenings. In experiment 2, the dream-lag effect appeared for references to the sleep lab experience in home dreams only among participants who had prior concerns about being in the lab.