It’s Possible to Learn in Our Sleep. Should We?
May 1, 2026Save this storySave this storySave this storySave this storyIn 1932, the inventor Alois Benjamin Saliger patented the Psycho-phone, a phonograph hooked up to a timer which could play recordings while a person was asleep. The audio could be heard at his dimly lit office on Lafayette Street, in Lower Manhattan. In one recording, titled “Prosperity,” Saliger intoned, “I have complete confidence in the Psycho-phone. It lulls me to sleep, but my unconscious mind hears and is deeply impressed by these affirmations. Money wants me and comes to me.” In another, titled “Mating,” he declared, “I radiate love. I have a fascinating and attractive personality. My conversation is interesting. My company is delightful. I have a strong sex appeal.”
An advertisement in Psychology magazine declared that, by listening to Saliger’s messages overnight, a person could get results that “would take months or years to accomplish by conscious effort.” The device cost up to two hundred and thirty-five dollars—more than four thousand dollars in today’s money. In 1933, a writer for this magazine visited Saliger and reviewed letters from satisfied customers. Some said that they’d lost weight or come into money. One claimed to be expecting a “Psycho-phone baby.”
People have long fantasized about learning effortlessly during sleep. What if you could snooze through “War and Peace,” or a Mandarin course, and wake up having absorbed it? In Aldous Huxley’s dystopian novel “Brave New World,” hypnopaedia—sleep education—not only teaches new languages but brainwashes people with government messaging. Many thinkers have reported that key insights came to them in their dreams. For the Russian chemist Dmitri Mendeleev, in 1869, it was the organization of the elements into the periodic table. For the novelist Mary Shelley, it was the plot of “Frankenstein.”
When scientists initially studied attempts to learn while sleeping, the results seemed promising. In a 1916 study, Navy soldiers seemed to better learn Morse code when it was played overnight. In 1942, a researcher tried to get twenty boys at a summer camp to stop biting their nails. Three hundred times a night, for almost two months, he played the phrase “My fingernails taste terribly bitter” through a loudspeaker; forty per cent of them stopped biting their nails, and none in a control group did. Participants in a 1952 experiment memorized more Chinese words when they heard vocabulary while asleep. But these early studies were deeply flawed—most significantly, because they couldn’t verify that test subjects were actually unconscious. Brain scans were not widely available, and there was scant knowledge of sleep stages such as REM sleep, when more vivid dreams take place.
Rasch and Arzi’s most significant findings were from sleep stages in which people dream less frequently. Emma Peters, a self-described “dream engineer” at the University of Bern, has instead conducted experiments on lucid dreamers while they are in REM sleep. In these kinds of experiments, participants are told to practice physical activities—finger tapping, coin tossing, dart throwing with a nondominant hand—within their dreams. After they wake up, they turn out to show more improvement on those tasks than a control group. (That said, dreams are not the most controlled environment. One dart-throwing dreamer was distracted by a volley of darts from a doll that suddenly appeared; this participant was not any better at throwing darts the next day.)
In perhaps the most striking example of learning during sleep, Konkoly, Paller, and several collaborators witnessed what amounted to conversations with people who were in the midst of dreams. Independent lab groups in the U.S., France, Germany, and the Netherlands asked lucid dreamers to answer yes-or-no questions and solve simple math problems. Electrodes measuring body and brain activity verified that the participants were not awake. Martin Dresler, a sleep researcher at the Donders Institute, who ran the Dutch experiments, said that they were able to verbally deliver new information to the sleeping mind—and to receive responses. Some people could remember the questions they had been asked when they woke up. “This is a form of very complex learning,” he told me.
Christopher Mazurek, one of the participants in the study, was nineteen at the time. He recalled hearing a math problem—eight minus six—during a lucid dream. He doesn’t remember what the dream was about—“something about my favorite video game,” he told me—but he knew that the question came from beyond the dream. He was instructed to respond by moving his eyes from left to right, and sure enough, the researchers counted two rightward movements of his eyes. Other participants experienced the sounds within the context of their dreams; in one, the question seemed to emanate from a dream radio. Thomas Andrillon, a sleep neuroscientist at the Paris Brain Institute who was not involved in the research, called it “one of the most mind-breaking papers I’ve ever read.”
Once, in Paller’s lab, Bark-Huss dreamed that she crashed her car. She was convinced that she’d spent too much time as a study participant and had become sleep-deprived. She saw flashing lights that she interpreted as the police. “I was freaking out because I thought I might have killed somebody,” she told me. “Then I realized, It’s not the cops. I’m in the lab now, and that’s the light from the lab.” She was able to communicate with Konkoly using eye signals—and, through it all, she continued sleeping. She remembered finding it eerie to come across signals from the waking world. “You realize that somebody is communicating to you from what feels like another dimension,” she said.
Konkoly’s study of problem-solving was published earlier this year, in Neuroscience of Consciousness. Twenty lucid dreamers, including Bark-Huss, spent multiple nights in the lab, trying to work out puzzles in their sleep. Each puzzle was paired with a specific sound, which was supposed to prompt them to resume work on the associated puzzle. One participant dreamed of asking for help from a fellow-passenger in a car. “I actually don’t know,” the passenger replied. “It’s kind of hard.” Another dreamed of solving the puzzle when it appeared on a school exam; upon waking, the solution was apparent in real life. In the lab, participants figured out forty-two per cent of the puzzles that showed up in their dreams. They solved only seventeen per cent of the ones that didn’t.
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Shayla Love is a journalist who writes about science, health, and the mind.Read MoreOpen QuestionsIs It Wrong to Write a Book with A.I.?