Why Do We Dream?

Have you ever wondered why we dream? What's happening inside our brains while we sleep? In this article, we'll delve into the scientific study of dreaming, also known as oneirology, and explore some popular theories behind why we dream.

For most of human history, the study of dreams didn't really exist because dreams are difficult to measure. You can't hold a dream, taste it, or see other people's dreams, and if you ask them to tell you what they dreamt, the results are almost always unreliable. In fact, it's estimated that we forget 95% of the dreams we have, especially within the first 10 minutes of having them.

But in 1952, researchers at the University of Chicago found a unique type of electrical activity that occurs during a certain stage of a person's sleeping. This is the Rapid Eye Movement (REM) stage. When researchers awoke people during this stage, they almost always reported that they had been dreaming. Also, at the same time during this stage, people's eyeballs are rapidly darting all over the place underneath their eyelids. If you watch people sleep during REM sleep, some pretty bizarre stuff happens.

If you look at the electrical activity of a brain that is in REM sleep, it almost exactly mimics the way the brain acts when it's awake. The biggest difference being that the production of chemicals inside the brain, like norepinephrine, serotonin, and histamine, is almost completely blocked, and that causes the muscles to stop moving, which is why you can dream about flying or running around or fighting ninjas, but your body doesn't move. People who have a disorder achieving complete REM, called REM sleep behavior disorder (RBD), move around in their sleep and act out their dreams. They can even get out of bed and sleepwalk.

Lucid dreaming is another fascinating phenomenon. It's when you're inside a dream and know that you're dreaming. While in a lucid dream, you can make conscious decisions about what you do. Achieving a lucid dream is quite elusive, but there are some tips and tricks on how to achieve one.

Researchers were able to deprive mice of REM sleep by using an inverted platform inside a tub of water. When that happens, the mouse can still fall into non-REM sleep, but as soon as they reach REM sleep and their muscles relaxed, they fall off the platform into the water, waking up. What they found was that when mice are not allowed to achieve REM sleep, they have an incredible amount of trouble remembering things. This happens in humans too. If you have people remember word pairs and then don't allow them to sleep the next day, their memory for that stuff is incredibly terrible.

Many popular theories about why we dream are variations on the idea that while we sleep, the unconscious part of our brain is busy organizing memories and strengthening connections from the day before that we need in the future, while getting rid of the junk that would otherwise clog the brain. While doing so, the brain is replaying those electronic impulses, and our conscious brain is detecting them, trying its best to create a cohesive story, creating a dream. This would explain why dreams are often so fantastic and seemingly random. They're not supposed to make sense; they're not an actual message from our brain. It's just the results of our cortex trying to synthesize the noise coming from all the work being done back in the unconscious.

Under this way of thinking, dreams are an epiphenomenon. They're not a primary process that has a purpose. Instead, they're the accidental result of a more important process going on behind the conscious brain. But some researchers don't believe in this theory and instead argue that dreams serve an important function in the brain. One such theory is that dreams help with memory consolidation, as the brain replays and processes the events of the day during sleep. Another theory suggests that dreams are a way for the brain to work through and process emotions and experiences, allowing individuals to better cope with stress and trauma. Still, others believe that dreams serve a more evolutionary purpose, such as allowing the brain to simulate potential scenarios and prepare for future challenges. Despite ongoing research, the exact purpose and function of dreams in the brain remain a topic of debate and exploration.