

Scientists Just Changed the Rules of What You Can Do While You Sleep

A new experiment shows it's possible to talk to dreaming people—and actually hear back.

man floating in mid air, sleeping
C.J. BurtonGetty Images
  • It turns out lucid dreamers can go one step further and answer questions while sleeping.
  • Scientists used sleep study technology to measure and cue dreamers to do math.
  • The sleepers remembered cues from waking life to do during sleep.

    Scientists at Northwestern University are doing a dream job—literally: they’re questioning people who are deep in dream-filled REM sleep. The crazy part? Those dreamers are actually answering basic questions by moving their eyes back and forth.

    By prompting people to lucid dream and asking questions, these scientists are proving dreams are permeable in both directions. That’s big.

    We’ve known for a while that dreams can include things prompted by real life, like a monster that turns out to be a stifling pillow or an alarm clock noise that joins the dream action. But this is one of the first experiments to show that people having dreams can reach out from their dreaming state into real life.

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    “Individuals who are asleep and in the midst of a lucid dream (aware of the fact that they are currently dreaming) can perceive questions from an experimenter and provide answers using electrophysiological signals,” the researchers write in Current Biology.

    In the study, the subjects exhibited “various capabilities” during REM sleep, the scientists say, including making “distinctive eye movements and selective facial muscle contractions” and correctly answering questions “on 29 occasions across 6 of the individuals tested.”


    Polysomnography, a fancy word for sleep study, “records your brain waves, the oxygen level in your blood, heart rate and breathing, as well as eye and leg movements during the study,” according to the Mayo Clinic.

    In this study, the researchers had subjects move their eyes back and forth to count out numbers—for example, eight minus six, so they’d move their eyes back and forth two times. The scientists gave the subjects instructions while they were awake that they carried into their lucid dreams and remembered to be able to do on cue.

    sleep study diagram
    IN (lower left) refers to methods whereby information was transmitted from experimenter to dreamer. OUT (lower right) refers to methods whereby information was transmitted from dreamer to experimenter. Examples of three dreams (color-coded for each input method) are illustrated below relevant excerpts from corresponding dream reports obtained following awakening.
    Konkoly, et. al./Current Biology

    The Northwestern study is very small, with just six people out of 36 who were able to both have lucid dreams and register correct answers to questions from inside. But if that number reflected the larger population, it would mean over 15 percent of people might lucid dream and be able to communicate in this way.

    To make sure the subjects were really, truly in REM sleep, the scientists used the full capability of their polysomnography setup to measure “sleep physiology,” like a highfalutin’ version of waving your hand in front of someone’s face. One obstacle is that REM sleep must be “stabilized,” the scientists say, because even the eye movements themselves can wake people up sometimes.

    Benjamin Baird, a sleep researcher at the University of Wisconsin–Madison who wasn’t involved in this study, told Scientific American the findings “challenge our ideas about what sleep is.” SciAm has more:

    Sleep has classically been defined as unresponsiveness to external environmental stimuli—and that feature is still typically part of the definition today, Baird explains. “This work pushes us to think carefully—rethink, maybe—about some of those fundamental definitions about the nature of sleep itself, and what's possible in sleep.”

    The idea of learning during sleep has long become a sitcom cliché—someone listens to a dating tape or a stop-smoking tape, for example, and suddenly acts odd because of subliminal cues. But this research indicates that people might really be able to study while asleep in a way that could help their waking life, like memorizing facts or visualizing high performance sports or music.

    “In addition, interactive dreaming could also be used to solve problems and promote creativity,” the researchers conclude. “The next moonshot ideas could be produced with an interactive method that can combine the creative advantages of dreaming with the logical advantages of wake.”

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