For all our technological advancements, the nature of dreams still largely eludes our scientific understanding. One little-understood concept — mutual dreaming — makes an appearance in Season 2 of the hit Netflix sci-fi show Alice in Borderlands, and it raises an interesting question: can two or more people independently experience the same dream?
Warning! Spoilers ahead for Alice in Borderland Season 2.
Alice in Borderland, a sci-fi dystopian thriller, is set in some alternate-world Tokyo where the survivors are forced to engage in battle royale life-or-death games. At the end of Season 2, it’s revealed that these characters were all crossing a major intersection in Tokyo when a meteorite crashed into the city. They subsequently fell into a coma and were thereafter in limbo — a borderland — between life and death. The characters who survive the death games in this alternate reality eventually wake up from their coma.
The closest real-world analog we have to what the characters go through is some kind of shared dream in a parallel universe. Mutual dreaming might seem hokey, but it’s actually not scientifically implausible — though still highly unlikely to occur.
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Why do we dream?
“Dreams have been a topic of interest for humanity for millennia,” Moran Cerf, a professor of business and neuroscience at Northwestern University, tells Inverse.
Deirdre Barrett, Harvard university dream researcher and author of The Committee of Sleep, says people would go to temples in ancient Greece to either receive dream guidance or try to cultivate specific dreams with help from the gods — a sort of spiritual “dream incubation.”
In the Western world, dream analysis really took off with Freud, who posited that dreams were a way to explore our unfulfilled wishes from our waking lives — an idea that’s contested to this day.
Psychologists have been studying the topic for decades, but neuroscience research on dreams has been slower to catch up and has only progressed in the past ten years. Cerf explains that most dreams occur during rapid eye movement (REM) sleep — a time of significant brain activity.
“Every 90 minutes, you have a short window of time where your brain essentially creates the infrastructure for dreams,” Cerf says.
We usually forget dreams after they happen, and Cerf says that’s by design — our brains don’t want our dreams cluttering our waking minds. For that reason, it’s helpful to be able to study our brains while we’re asleep instead of just relying on dream diaries written after a person wakes up.
But if we forget our dreams, what evolutionary purpose do they serve? Cerf says there are multiple theories, but two schools of thought tend to dominate dream science.
The first asserts dreams are basically a way for the brain to activate the visual part of the mind while we’re sleeping — since our eyes are closed and not delivering information to the brain — and ensure we can still see when we wake up.
“We hate this theory because it means that dreams mean nothing and all these stories that we build and the experience that we have and all the kind of importance that we assign to them is useless,” Cerf says.
Instead, he favors a second school of thought, which holds that dreams are basically our brains’ default mode of virtual reality. Imagine you get a job offer in another state but are uncertain about whether to accept the offer. You might dream about an alternate reality in which you live in that other state as a way of testing out that future. When you wake up, you might feel better equipped to make a decision.
“Even though you forget the actual dream, and you forget what happened, what stays are all the decision-making processes and the emotions,” Cerf explains.
So, Freud may have been onto something after all. We know the emotional impact of dreams can linger long after we forget them, and Alice in Borderland knows it too. Even though the two lead characters, Usagi and Arisu, forget their alternate lives in the battle royale world, they faintly recognize each other when they wake up in the hospital, suggesting the friendship they built in the borderland will have lasting impacts on their real-life relationship.
What is mutual dreaming?
In Alice in Borderland, characters’ minds undergo a shared set of grueling fights to the death while their bodies are simultaneously struggling to awaken from a coma. Taken a certain way, we can interpret the show as a form of mutual dreaming, in which each person separately experiences the same dream.
Both Cerf and Barrett say there are shared dream topics that people across the world will experience again and again. Dreams of teeth falling out, delivering a presentation in your underwear, and failing an exam or class are all common examples of recurring dreams.
Similarly, traumatic events can linger in the collective consciousness and percolate into our dreams. Cerf says that after the 9/11 attacks, many Americans reported dreams involving falling, and he could imagine people in Japan having similar shared dreams should a meteorite hit Tokyo — as happened in Alice in Borderland. A survey Barrett conducted after the Covid-19 pandemic showed many people reporting dreams of getting sick with the virus, or, more bizarrely bug attacks — perhaps a shared metaphor for disease.
“I think the most common explanation is that there are a lot of psychological waking life things that could contribute to forming a lot of the same symbols,” Barrett says. “People may share a set of not just common experiences, [but] common metaphors and symbols for the world.”
But while these dreams might follow a shared theme, people aren’t literally experiencing the same dream. In rare cases, Barrett says that people have reported having nearly the exact same dream. These dreams take two forms: individuals experience the same dream from the same perspective. And in other dreams, two or more people will encounter each other from a reciprocal perspective — in other words, they meet up in a mutual dream.
The latter is more akin to what happens in Alice in Borderland, where strangers encounter each other in a dream world. A 2017 study of mutual dreaming found that while most mutual dreams took place between relatives, friends, or significant others, roughly four percent involved “non-familiar people.”
Barrett says that people with vivid dreams will often take an interest in mutual dreaming, finding similar people on online forums and forming meetup groups to try to encounter these familiar faces in their dreams. But these reported mutual dreams usually don’t hold up under scientific rigor.
“It does not tend to stand up very well to research — when you start this getting people to write down [mutual] dreams, it’s not happening more than chance,” Barett says.
So is Alice in Borderland plausible?
Right now, there isn’t much scientific basis for mutual dreams a la Alice in Borderland. But there are scientific techniques that could get us closer to unlocking mutual dreams.
Barrett explains a technique known as “dream incubation” where you use self-suggestion before falling asleep to try to achieve a particular dream. According to a 2021 Current Biology study, researchers were able to successfully communicate with people while they were lucid dreaming — a state in which the person is aware they are dreaming but still asleep. The dreamers used eye signals to answer questions the researchers posed.
It’s possible you could use a combination of dream incubation and similar techniques to the ones the researchers in the 2017 study did to allow for shared communication — and possibly even mutual dreams — between two dreamers. But that hasn’t been scientifically observed.
“It's theoretically possible, but that one hasn't actually been done as an experiment yet,” Barrett says.
Cerf says the closest researchers have come to incubating mutual dreaming is a study done over twenty years ago, when researchers had participants play a game of Tetris before falling asleep, and several individuals reported dreams of falling bricks afterward.
Before we can scientifically incubate mutual dreaming, we need to better how we can influence or control dreams in a single individual. A lot of dream research involves using electroencephalogram (EEG) to record brain activity, but Cerf’s research goes further and uses a device known as TMS to “zap” or stimulate the sleeping brain to induce lucid dreaming, allowing the participant to interact with the outside world while dreaming.
“That essentially takes over your dream, so to speak — it starts controlling it,” Cerf says, “What this does, is it essentially wakes you up without waking you up.”
Since Cerf’s team also works with patients undergoing brain surgery, they can also insert in-brain electrodes to “see their dreams from the inside” in a more precise way than EEG.
Cerf says he’s never tried to do this same experiment with two people at once so it’s not impossible for researchers to induce mutual dreaming, but it’s still in the realm of science-fiction. So we probably won’t be meeting up with strangers in life-or-death dreams anytime soon. But it’s sure fun to imagine.
Alice in Borderland is streaming now on Netflix.
