The Science of Dreams

Today, we’re diving into the fascinating world of dreams and exploring what happens inside our brains while we sleep. The scientific study of dreams is known as oneirology, but for most of history, this field barely existed. The main reason? Dreams are elusive—they can’t be touched, measured, or observed directly. You can’t taste or see someone else’s dream, and even if you ask people to describe their dreams, the results are often unreliable. In fact, it’s estimated that we forget about 95% of our dreams, especially within the first 10 minutes after waking up.

But in 1952, something remarkable happened. Researchers at the University of Chicago discovered a unique type of electrical activity that occurs during a specific stage of sleep. When they woke people up during this stage, they almost always reported that they had been dreaming. This stage is known as REM (Rapid Eye Movement) sleep, and during it, a person’s eyes move rapidly under their eyelids—a phenomenon you can actually observe if you watch someone sleep.

During REM sleep, some pretty strange things happen in the brain. The electrical activity in a brain during REM sleep is almost identical to that of an awake brain, with one significant difference: the production of certain chemicals like norepinephrine, serotonin, and histamine is almost completely blocked. This chemical suppression causes the muscles to become paralyzed, which explains why you can dream about running, flying, or fighting ninjas without physically moving. However, people with a disorder that prevents complete REM atonia (muscle paralysis during REM sleep) can move around in their sleep, sometimes even acting out their dreams or sleepwalking.

It’s also possible to wake up and find yourself temporarily unable to move. This occurs because your body is still in a state of REM atonia, even though you’re fully conscious—a phenomenon known as sleep paralysis. On the flip side, there’s lucid dreaming, where you become aware that you’re dreaming while still in the dream. Lucid dreaming is particularly intriguing because it allows you to make conscious decisions within your dream, like flying or having a tea party with historical figures. However, achieving lucid dreaming is not easy. There are techniques and tips to help, like those found in a Howcast video, which I’ve linked in the description.

Researchers have even gone so far as to deprive mice of REM sleep to study its effects. They used a method where the mice were placed on a small platform in the middle of a tub of water. The platform was just large enough for the mouse to sit on, but when the mouse entered REM sleep and its muscles relaxed, it would fall off into the water and wake up. This experiment revealed that mice deprived of REM sleep had significant trouble remembering things. The same holds true for humans—if people are deprived of sleep, especially REM sleep, their ability to remember things like word pairs or newly learned tasks deteriorates dramatically.

But REM sleep isn’t just important for memory. If you learn a difficult new task, like playing an instrument or solving a complex puzzle, your brain will replay the electrical activity associated with that task while you sleep, whether you’re aware of it or not. This has led to popular theories suggesting that dreams might be a byproduct of the brain organizing and strengthening memories from the day while discarding unnecessary information.

According to this theory, the electrical impulses generated by the unconscious brain during memory consolidation are detected by the conscious brain, which then tries to create a cohesive story out of them—resulting in dreams. This might explain why dreams often seem so random and nonsensical; they’re not intended to make sense but are simply the brain’s attempt to interpret the noise coming from the unconscious processes.

However, not everyone agrees with this interpretation. Some researchers believe that dreams serve a primary purpose, specifically in preparing us for threats. This theory suggests that the negative emotions commonly experienced in dreams, such as anxiety, anger, and abandonment, are part of an evolutionary mechanism. Early humans, who lived in uncertain and dangerous environments, may have developed the ability to simulate potential threats in their dreams, allowing them to better cope with real-life anxieties.

The theories we’ve discussed are popular, but there’s no consensus on them, and they barely scratch the surface of the scientific study of dreams. Dreams remain one of the most mysterious aspects of human experience. To put it in perspective, we know a great deal about distant phenomena like the Eagle Nebula, a massive structure in space 6,500 light-years away. We understand its composition, size, and even its future trajectory. But despite our knowledge of the universe, we still don’t fully understand why we dream or what dreams truly mean. And that mystery is part of what makes dreams so fascinating.