The health benefits of getting a good night's sleep are widely known. But if you weren't already committed to getting enough shut-eye, here's yet another reason to make it a priority: You're missing a potentially vital opportunity to practice essential survival skills.
That's the theory explored by a recent report from Nautilus, which focuses on the science of dreaming. For a long time the general consensus has been that dreams, be they delightful or terrifying, are useless: a mish-mash of experiences, impulses, memories, and that random episode of The Walking Dead that you watched just before bedtime, all distilled into a surreal nightmare in which you're being chased through the halls of your old high school by zombies … and for some reason, you're not wearing pants.
But some researchers have found evidence for an alternative possibility: that dreams are a form of threat simulation, readying your brain in the rare event that you do find yourself confronted (pantsless or otherwise) with a dangerous situation.
According to this theory, outlined by cognitive researcher Jim Davies, dreams act as a dress rehearsal for dangerous scenarios in real life. Support for the idea comes in several forms, beginning with the fact that our most vivid and memorable dreams tend to be more like archetypal nightmares.
"They have a tendency to feature negative emotions—fearful, angry, and anxious dreams are more common than happy ones," Davies writes. "And the things we dream about tend to be biased in the direction of ancient dangers rather than more modern ones. We dream about being chased by animals and monsters more than having our credit card defrauded, even though most of us have very little real-life experience of being chased by animals (or monsters)."
Additionally, there are clues to the purpose of dreaming in the way the human subconscious responds to real-world events. In 2008, researchers at Tufts discovered a shift in the way people dreamed immediately after 9/11, as dreams about being attacked increased in intensity and frequency. But while people were having more and worse nightmares, they weren't about plane crashes or terrorism; the central imagery of their dreams remained unchanged, suggesting that their brains were reaching for an ancient script about being under threat —and rehearsing for the possibility of a future catastrophe—rather than reliving the memory of the recent tragedy. Per the researchers, the evidence pointed to dreams being an "emotionally guided construction or creation, not a replay of waking experience."
Another curious link between dreaming and disaster-preparedness: the phenomenon of prescient dreams. Though not formally researched, anecdotes abound from people who've dreamed of a frightening experience only to then live through it in real life. For instance, in 1983, 20-year-old painter James Murphy III survived a terrifying fall from his job site atop the Rip Van Winkle Bridge in upstate New York, plummeting more than 150 feet into five feet of marshy water on the coast of the Hudson River. In an interesting wrinkle, Murphy's mother reported that he had dreamed about falling the previous night, and that in the dream, he took a tuck position upon entering the water, protecting his head and neck—a move he repeated the next day when he plunged into the Hudson. Did dreaming his way through the fall beforehand contribute to Murphy's quick thinking, and subsequent survival, in that critical moment? The theory of dreams as threat simulation suggests that the answer is yes.
There's a lot to learn yet about why and how we dream, and per Davies, the most likely explanation is that dreaming is a multi-faceted and multi-functional process. But in the meantime, everything we know about the usefulness of mental "practice" supports the idea that dreams help prepare you to navigate the waking world. Studies show that visualizing yourself performing a skill makes you substantially better at it. And for the minority of people who are capable of lucid dreaming—the practice of recognizing when you're in a dream and taking control of the narrative—there's no end to the things you can learn to do while you're asleep.
"You can rehearse any skill in a lucid dream," Daniel Erlacher, a researcher at the University of Bern, Switzerland who led a study in which lucid dreaming led to improved performance in a coin toss game, told the Harvard Business Review. "It has been well established that athletes who mentally rehearse an activity can improve their performance, and it makes sense that dreams can achieve the same effect."
And much like the reports of prescient dreaming, anecdotal evidence certainly supports the concept of rehearsing for real life in your dreams (be they lucid or not). German researcher Paul Tholey, who founded the scientific study of dreams (oneirology), for one, used himself as a guinea pig.
"He claimed that by practicing in his dreams, he’d learned to snowboard so well that he could do it without bindings, which is almost impossible," said Erlacher. "I’ve spoken with people who went snowboarding with him, and they watched him do it. So there has been some validation."