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In a dark room, in the middle of the night, a woman lies dreaming. Suddenly, her eyes beneath their lids dart crisply left-right, left-right. The eye signal means she knows she’s dreaming.

Lucid dreamers are people who can recognize that they are dreaming and, in some cases, control the content of their dreams. For scientists, they have proven a crucial link to this nightly hallucinatory state. In a new paper in the journal Neuroscience of Consciousness, researchers asked dreamers, both lucid and otherwise, to dream about solving a specific puzzle they’d failed to solve before falling asleep. While the study was small, the team saw signs that dreaming about a puzzle was linked to being able to solve it the following morning–although, intriguingly, normal dreamers were more successful than lucid ones.

A mysterious landscape

For many years, dreaming was seen as more or less impossible to study scientifically, says Robert Stickgold, a professor at MIT who studies dreaming and memory. The verbal reports of people who’ve just woken up are not strictly speaking an unbiased source of information—you’re just going on their say-so that they dreamt, and what they dreamt about.

Still, scientists have devised clever ways to investigate how sleep and dreams can affect us. Studies have looked at whether playing sounds or providing other prompts during different stages of sleep can influence what people are capable of when they wake up. One recent study found that providing cues to remind people during Rapid Eye Movement (REM) sleep, when most dreams are thought to happen, about a process they had been learning led to better performance later. 

As well, in recent years, researchers have found ways to influence dreams by communicating with people while they are in a lucid state. In 2021, Ken Paller and Karen Konkoly of Northwestern University and their colleagues reported that they had established two-way communication with lucid dreamers, tapping their hands in a specific pattern and having them signal back with eye movements. The sleeping subjects received math questions and dreamed about the solutions, relaying them to the experimenter. This work opened the door to someday, perhaps, asking people in real time what they are dreaming about.

It is still unclear however, whether dreams might have some benefit for us, such as helping us work through issues we encounter during the day. It certainly feels that way—but proving it is far more difficult.

“How do dreams contribute to our creativity and problem solving abilities in the waking state?” asks Paller. “You could ask that by giving people problems before they go to sleep, and see if they come up with the answers when they wake up. But then, you’ll never know if it was because of what they were thinking about before they went to sleep, or as they were going to sleep, or any other time period–not their dreams.”  

Dreaming of solutions

In this new study, to explore whether explicitly dreaming about a problem can help people find solutions to it, Paller, Konkoly, and their colleagues had 20 subjects work on a set of logic puzzles. Each puzzle had a separate soundtrack that played while they worked on it. Then, as the subjects got ready to sleep in the lab, researchers explained that the soundtrack for a randomly selected puzzle they hadn’t been able to solve would play once they reached REM sleep. This was their cue to keep working on the puzzle in a dream. 

No one knew ahead of time which puzzle they’d be asked to solve. That meant the researchers could see whether dreaming of the specific puzzle was linked to solving it later. If dreamers found themselves lucid, the researchers asked them to announce the fact with an eye signal. In the morning, subjects reported their dreams to the researchers and had another chance to work on the puzzles. 

Some people dreamed of puzzles, some didn’t, some were lucid, some were not. Interpreting the data proved tricky, but one thing did come clear, says Konkoly. People who dreamed of the puzzles did tend to be more successful at solving them in the morning. 

Contrary to what Konkoly expected to see, “we had a lower solving rate for puzzles incorporated into lucid dreams,” she says. You’d think that being aware of dreaming and being able to control events would lead to better problem solving. But that doesn’t seem to be the case.

“One theory of creative problem solving is that during wake, you become fixated on an incorrect solution path, and then you forget that during sleep,” Konkoly says. That allows your mind to find the right answer, without interference. Asking people to bring deliberate focus to solving a puzzle during a lucid dream might prevent that forgetting, she speculates. 

Another theory is that lucid dreams might be too much like waking consciousness to help with solving problems. “Your unconscious mind has all this plurality of simultaneously thinking about 10 things at once…It’s not limited by a single track,” Paller muses. “And maybe that’s more creative, in a sense. Maybe lucidity is therefore antagonistic, because you want to not just focus on one thing, but focus on a whole bunch of things.”

The results tally with findings from other work on dreaming and creativity, says MIT’s Stickgold, who was not involved in the study. He points to a 2023 study from his group, led by Adam Horowitz, in which subjects were asked before sleeping to dream of trees. Upon waking, they were presented with tests of creativity around the theme of trees. While the study couldn’t control for what people were thinking about before they went to sleep, the way Paller and Konkoly’s study does, “the more references they had to trees in their dreams, the more creative they were,” Stickgold says. That suggests that priming people to dream about a subject can change how they think about it later.