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It sounds straight out of a sci-fi movie. Some people are aware of their dreams while dreaming and can even steer themselves into this state of so-called lucid dreaming—and even exert some control over what happens.
Lucid dreams, which can be good, bad, or nightmarish, are notoriously difficult to study. Much remains in the realm of hypothesis, the anecdotal, and the stuff of Hollywood.
But there’s no doubt lucid dreaming is real, and the science of it is getting strange. Scientists have figured out how to hack into lucid dreams and communicate with people while they have them. Tech companies are working to invent devices to induce lucid dreaming, and researchers are eager to use lucid dreams to better understand the mysteries of our nighttime fantasies: what’s going on in our sleeping minds and why we dream at all.
What are lucid dreams, and when do they happen?
In lucid dreams, people are physiologically asleep yet aware they are dreaming. The phenomenon is not new—Aristotle referred to it, though he had no name for it. In the 1970s, scientists began to objectively verify that lucid dreaming is real, in part by having study participants indicate the start of lucid dreams by moving their eyes in patterns that they agreed upon while they were awake. They also found lucid dreaming elevated participants’ heart rates and breathing compared to regular dreaming (Baird, 2019).
Some people can alter the course of their lucid dreams, affecting the plot or the outcome (Schredl, 2018). The promise of dream manipulation is incredibly alluring. Think of it as entering an altered state of consciousness in which you might engineer a dream of doing something you can’t do in real life, like flying. Some people hope to exert control over their lucid dreams to promote their own well-being or psychological growth, solve problems, or overcome fears. Evidence suggests, however, that controlling events in lucid dreams is a rare accomplishment (Soffer-Dudek, 2020).
About 55% of adults say they’ve experienced lucid dreaming at least once, and nearly a quarter claim they have them frequently (Saunders, 2016). About one percent of people are thought to have them several times a week (Erlacher 2020).
If all goes well, a night in bed involves a series of repeated cycles of deep sleep, lighter sleep, and wakefulness. During deep sleep, the brain is largely ignoring sensory input. But during REM (rapid-eye movement ) sleep, we’re closer to being awake, and images and other sensations—the stuff of dreams—flit about (NIH, 2019).
Like most dreams, lucid dreams usually happen during the REM phase (Erlacher, 2020).
Scientists have long pondered whether dreams are mere imagination or if, in the brain, they’re more akin to actual perception. In one study of lucid dreamers, scientists concluded that dreaming activates the same brain areas as does perception and that the visual imagery of REM-sleep dreams “is more similar to perception than imagination.” In fact, researchers think some of the rapid eye movement might relate to scanning the dream scene (LaBerge, 2018).
How to have lucid dreams
Lucid dreams can occur spontaneously, without trying to induce them. But the practice of kickstarting them is becoming increasingly popular, with thousands of people joining forums and following blogs on the topic (Soffer-Dudek, 2020).
Going back three decades or so, dozens of techniques have been proposed for inducing lucid dreams. The results for most of them have been inconsistent at best, but a few have proven promising (Erlacher 2020).
A handful of techniques are cited frequently in the scientific literature and were tested in one of the largest studies on the topic (Aspy, 2020):
Mnemonic induction of lucid dreams (MILD)
After waking up from a dream and while aiming to go back to sleep, you create a “memory intention” by repeating a phrase like “next time I’m dreaming, I will remember I’m dreaming.”
Senses initiated lucid dream (SSILD)
This one also involves waking up after a few hours of sleep, then closing your eyes and shifting your attention repeatedly between senses:
- Focus on your closed eyelids without trying to actually see anything.
- Then focus on sounds, whether outside, in your home, or in your body.
- Now focus on physical sensations—air temperature, the weight of your blanket, your heartbeat; you might feel tingling or a sense of spinning.
This involves waking up after five hours of sleep, perhaps by setting an alarm, then going back to sleep to dream some more. It is often used in conjunction with MILD and SSILD.
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Reality testing (RT)
Similar to what the protagonist does in Christopher Nolan’s blockbuster “Inception” (more on that below), you develop a test to prove if you are awake or dreaming, such as checking your environment throughout the day to see if you’re dreaming. The idea is it’ll become a habit, so you’ll do it while dreaming and trigger lucidity (Aspy, 2020).
The large study noted above, involving 355 people interested in lucid dreaming, found that the MILD and SSILD techniques, each used in conjunction with WBTB, were similarly effective. After a week of journaling their dreams, the participants were divided into separate groups to practice the various techniques. MILD induced lucid dreaming for 16.5% of them, and SSILD worked for 16.9 percent. The RT method did not work, just as it had not in several previous studies by other researchers (Aspy, 2020).
Another study found the combination of WBTB and MILD can effectively induce dreams in people even if they had no previous ability with lucid dreaming (Erlacher, 2020).
What actually causes lucid dreams?
The specific neurobiology of lucid dreaming—what happens in the brain and why some people can do it easily and some cannot—is unknown. But evidence suggests at least two brain areas are involved: the anterior prefrontal cortex and the parietal cortex (Baird, 2018).
Brain images reveal that the anterior prefrontal cortex in lucid dreamers is larger than in people who don’t dream lucidly. This part of the brain normally plays a role in self-reflection, so scientists speculate that people who have lucid dreams are probably more self-reflective during their waking hours (Filevich, 2015). But scientists still don’t understand why the techniques proven to induce dreams actually work.
With the SSILD technique, the thinking is that it creates a heightened awareness of stimuli, which carries into the next round of sleep. One study participant had this to say: “As I was drifting off to sleep, I found myself continuing to do the technique, even though I wasn’t trying to” (Aspy, 2020).
Are lucid dreams useful?
Various studies have suggested that lucid dreaming might be harnessed to treat nightmares, enhance problem-solving creativity, or even improve skills via dream rehearsal. But research into these possibilities has yet to yield firm results (Aspy, 2020). A review of scientific literature on using lucid dreams to control nightmares concluded that though it might be feasible, the studies are mostly small, and the overall body of research is inconclusive (de Macêdo, 2019).
Nightmares: causes, symptoms, and how to stop them
In one study, 20 of 39 people who reported lucid dreaming during nightmares could not alter the plot. However, ten said the awareness either reduced their anxiety or resulted in changing the course of the dream, and nine others said they used their lucidity to wake themselves up (Schredl, 2018).
Regardless, the American Academy of Sleep Medicine includes lucid dreaming as a useful therapy for nightmare disorders (Morgenthaler, 2018).
Could lucid dreaming be dangerous?
While there is no comprehensive evidence suggesting any danger to lucid dreaming, in some cases, lucid dreams might do more harm than good. It’s possible that lucid dreams could disrupt the boundary between reality and fantasy for other people, with possible consequences we don’t yet understand. And on a more basic level, inducing lucid dreams might disrupt sleep quality (Soffer-Dudek, 2020).
From Hollywood to your bedroom
Whether lucid dreaming is considered helpful, dangerous, or just interesting, many scientists, entrepreneurs, and enthusiasts would like to figure out how best to induce the phenomenon.
Several drugs have been proposed for triggering lucid dreaming, from alcohol to LSD to obscure chemicals with names like AChEI galantamine. Some have been tested, but there’s no clear evidence that any of them are effective. Likewise, tests using electrical brain stimulation to induce lucid dreams are so far inconclusive (Baird, 2019).
Hollywood, however, has it all figured out.
The 2010 Christopher Nolan film “Inception,” starring Leonardo DiCaprio, is a nightmare of a movie. DiCaprio’s character, a professional thief, uses lucid dreams and Hollywood-devised dream-sharing technology to hack into people’s dreams, steal corporate secrets, and then implant an idea in someone else’s mind.
While some of the “Inception” plotlines may seem far-fetched, the broad premise is closer to reality than you might think.
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Scientists developed a mask that detected REM sleep more than two decades ago and used flashing lights to cue lucid dreaming. Newer, similar masks are sold commercially, and other modern devices in development are said to detect brain waves thought to be associated with REM sleep. Some commercial and lab devices employ sound, light, and even vibrations to trigger lucid dreaming. However, objective studies on these products are lacking, so it’s unclear how promising they might be (Mota-Rolim, 2019).
But in one of the most vivid examples of sci-fi becoming a reality, scientists have now hacked into people’s lucid dreams and had two-way conversations as the dreamers slept.
While the participants had vivid, lucid dreams, some were able to answer yes-no questions from the scientists, follow simple instructions, and even do a little math. The lucid dreamers responded not by talking but through eye movements and contracting the muscles in their faces. The techniques didn’t work every time, but the findings suggest that “interactive dreaming” during lucidity could help scientists better understand the process and purpose of dreams (Konkoly, 2021).
“Dreams take us to a different reality, a hallucinatory world that feels as real as any waking experience,” the researchers wrote. “This relatively unexplored communication channel can enable a variety of practical applications and a new strategy for the empirical exploration of dreams.”
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Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.