Researchers have found that playing sounds associated with unsolved puzzles during REM sleep can help lucid dreamers solve those puzzles more effectively the next day. The study involved 20 participants who signaled awareness in their dreams through eye movements and sniffs. This technique, known as targeted memory reactivation, leverages the brain's memory processes to enhance learning during sleep.
A study conducted by Karen Konkoly at Northwestern University in Illinois demonstrates how sounds can influence dreams to aid problem-solving. The research, published in Neuroscience of Consciousness (DOI: 10.1093/nc/niaf067), involved 20 self-identified lucid dreamers. These participants attempted puzzles while awake in a sleep lab over two sessions, with each puzzle paired to a unique soundtrack, such as birdsong or steel drums.
Researchers monitored brain activity and eye movements to identify the rapid eye movement (REM) stage of sleep, when dreams are typically vivid and narrative-driven. During REM, they played soundtracks for randomly selected unsolved puzzles. Participants indicated lucidity by making at least two rapid left-to-right eye movements and confirmed hearing the sound and engaging with the puzzle through at least two rapid in-out sniffs.
The following morning, participants reported that hearing the soundtracks during sleep made puzzles more likely to appear in their dreams. Among those who dreamed about the puzzles, about 40 percent solved them successfully, compared to 17 percent of those who did not report dreaming about them.
This effect may stem from targeted memory reactivation, where the sound cues activate memories in the hippocampus, a key brain region for memory formation. Konkoly explains that REM dreams are "hyper-associative and bizarre," mixing new and old memories with imagination, potentially allowing access to less inhibited parts of the mind. "You have this brain that’s active [during this stage], but maybe with less inhibition, so you can reach farther into the corners of your mind," she says.
Tony Cunningham at Harvard University notes that the findings suggest "people may be able to deliberately focus on a specific unsolved problem while dreaming." However, he raises concerns about potential disruptions to sleep's restorative functions, such as clearing brain debris, and the risk of commercial exploitation, like advertisements in sleep devices. "Our senses are already assaulted from all directions by ads, emails and work stress during our waking hours, and sleep is currently one of the few breaks we get from that," Cunningham says.
Konkoly plans further research into why the same stimuli can produce varying results in individuals across different nights.
