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Why do we dream? It’s a question dream analysts and sleep researchers have been studying for years. Now new research suggests that some dreams may actually result from the brain’s effort to keep learning, even as we sleep.

In a study led by researchers at Beth Israel Deaconess Medical Center in Boston, 99 volunteers trained for an hour on a virtual maze, trying to find their way through the complicated, three-dimensional puzzle as quickly as possible. Then half the volunteers were allowed to sleep for 90 minutes. The other half stayed awake, reading or relaxing. During the resting period, the subjects were interrupted or awakened and asked to describe their thoughts or dreams.

After the resting period, the participants were asked to again tackle the maze. Those who hadn’t napped showed no improvement or did even worse after the break. Nappers who were rested but didn’t report any maze-related dreams did better but showed only marginal improvement.

However, four nappers who reported dreaming about the maze showed a startling improvement, cutting their completion time in half. The difference in scores before and after sleeping was 10 times higher for the maze dreamers than those who hadn’t dreamed about the task, according to the findings published Thursday in the journal Current Biology.

Even though the number of dreamers was small, the researchers noted that the gap in learning between the dreamers and nondreamers was so wide that the finding was highly statistically significant.

Notably, the dreamers had all performed poorly on the test prior to dreaming about it. That suggests that struggling with a task might be the trigger that prompts the sleeping brain to focus on the subject and work on getting better, explained the lead author, Robert Stickgold, a cognitive neuroscientist at Harvard Medical School.

“It’s almost as if your brain is rummaging through everything that happened today and deciding that you’re not done with it,” Dr. Stickgold said. “The things that really grip you, the ones you decide at an emotional level are really important, those are the ones you dream about. The things you’re obsessed with are the ones that your brain forces you to continue to process.”

The study subjects who dreamed about the maze didn’t dream about trying to complete it over and over. Instead, they simply dreamed about it in a variety of ways. One person said he dreamed about the music that played along with the task. Another dreamed about seeing people along checkpoints in the maze and remembering a bat cave he had once toured. Another dreamed of searching for something in a maze. The lesson may be that dreams don’t necessarily have to make sense or be obvious to the awake mind in order to have a learning benefit.

“It might be that sleep is the time when the brain is tuned to find those types of association you wouldn’t notice during waking,” Dr. Stickgold said. “It does this by focusing on weak associations. If that’s the case, the dreams you have in REM sleep might be so bizarre for exactly the same reasons. It’s not that the dreams make no sense. They make wacky sense.”

More study is needed to fully understand the power of dreams in learning. The researchers are planning a new study that “spiffs up” the maze tests using colors and images in a way that most likely will trigger an increase in dreaming among the study participants.

Whether someone can ultimately harness the power of dreaming to improve learning is an open question, but Dr. Stickgold does have a suggestion for students or others trying to master a task or study subject.

“If you’re a student and you want to do better on the test, you might need to dream about it,” Dr. Stickgold said. “The question is, ‘How do I get myself to dream about it?’ The answer is to get excited about it. That seems to be what you dream about.”