Combining Presleep Cognitive Training and REM-Sleep Stimulation in a Laboratory Morning Nap for Lucid Dream Induction

Previous experiments combining cognitive techniques and sleep disruption have been relatively successful in inducing at-home lucid dreams (LD) over training periods of 1 week or more. Here, we induce LD in a single laboratory nap session by pairing cognitive training with external stimulation. Participants came to the laboratory at 7:30 a.m. or 11:00 a.m. and during polysomnography setup were provided with information about lucid dreaming. For 20 min prior to sleep the experimenter played alternating audio and visual cues at 1-min intervals. Participants were instructed to practice a mental state of critical self-awareness, observing their thoughts and experiences each time they noticed a cue. This procedure associated the cues with the trained mental state. Subsequently, participants were allowed 90 min to nap, and the audio and visual cues were presented during REM sleep to activate self-awareness in dreams and elicit lucidity. A control group followed the same procedure but was not cued during sleep. All participants were instructed to signal their lucidity by looking left and right 4 times (LR signal). Signal-verified lucid dreams (SVLDs) qualified as dreams in which the LR signal was observed and the participant reported becoming lucid. Across the 2 nap times, this protocol induced SVLDs in 50% of cued participants. In the absence of cueing during sleep, participant SVLD rate was 17%. Of note, 3 successful participants had never before experienced a LD, suggesting this protocol may be effective across the general population. Implications of this Targeted Lucidity Reactivation protocol for nightmare treatment are discussed.