Experimentally provoking dreams of unsolved puzzles during REM sleep boosts creative problem-solving

Dreams have been a source of inspiration and creativity for millennia. Yet, demonstrating that REM-sleep dreaming promotes creative thinking has been challenging. Existing evidence does not provide strong support for this link; dream manipulations were generally confounded by waking activities that influenced dream content, such that any boost in creativity could be attributable to waking rather than sleep cognition. Correlational evidence cannot directly establish that dreams cause insights. Some studies indicate that memory reactivation during deep sleep or sleep-onset dreams can increase related creativity, but direct experimental manipulations of REM sleep dreams are still limited. Here, we aimed to engineer dreams by reactivating memories in people who frequently lucid-dream (i.e., realize they’re dreaming while still asleep). Participants slept after failing to solve several puzzles that had unique soundtracks, half of which were replayed during REM sleep (during lucid dreams when possible). Participants were instructed to continue working on a puzzle if they heard its sound in a dream. Sound cues during sleep increased the proportion of dreams related to associated puzzles, particularly in dreams containing lucidity signals. Cues also boosted later puzzle-solving, but only for participants who showed an increase in cue-related dreaming. Whereas it is well-known that sounds can be incorporated into dreams and change dream content, our experimental procedure promoted dreams pertaining to specific pre-sleep objectives. Results provide strong support for the conclusion that the specific content of REM-sleep lucid dreams can boost creativity that aids problem-solving.