The human brain is a mysterious little ball of gray matter. After all these years, researchers are still baffled by many aspects of how and why it operates like it does. Scientists have been performing sleep and dream studies for decades now, and we still aren't 100 percent sure about the function of sleep, or exactly how and why we dream. We do know that our dream cycle is typically most abundant and best remembered during the REM stage of sleep. It's also pretty commonly accepted among the scientific community that we all dream, though the frequency in which dreams are remembered varies from person to person.
The question of whether dreams actually have a physiological, biological or psychological function has yet to be answered. But that hasn't stopped scientists from researching and speculating. There are several theories as to why we dream. One is that dreams work hand in hand with sleep to help the brain sort through everything it collects during the waking hours. Your brain is met with hundreds of thousands, if not millions of inputs each day. Some are minor sensory details like the color of a passing car, while others are far more complex, like the big presentation you're putting together for your job. During sleep, the brain works to plow through all of this information to decide what to hang on to and what to forget. Some researchers feel like dreams play a role in this process.
It's not just a stab in the dark though -- there is some research to back up the ideas that dreams are tied to how we form memories. Studies indicate that as we're learning new things in our waking hours, dreams increase while we sleep. Participants in a dream study who were taking a language course showed more dream activity than those who were not. In light of such studies, the idea that we use our dreams to sort through and convert short-term memories into long-term memories has gained some momentum in recent years.
Another theory is that dreams typically reflect our emotions. During the day, our brains are working hard to make connections to achieve certain functions. When posed with a tough math problem, your brain is incredibly focused on that one thing. And the brain doesn't only serve mental functions. If you're building a bench, your brain is focused on making the right connections to allow your hands to work in concert with a saw and some wood to make an exact cut. The same goes for simple tasks like hitting a nail with a hammer. Have you ever lost focus and smashed your finger because your mind was elsewhere?
Some have proposed that at night everything slows down. We aren't required to focus on anything during sleep, so our brains make very loose connections. It's during sleep that the emotions of the day battle it out in our dream cycle. If something is weighing heavily on your mind during the day, chances are you might dream about it either specifically, or through obvious imagery. For instance, if you're worried about losing your job to company downsizing, you may dream you're a shrunken person living in a world of giants, or you're wandering aimlessly through a great desert abyss.
There's also a theory, definitely the least intriguing of the bunch, that dreams don't really serve any function at all, that they're just a pointless byproduct of the brain firing while we slumber. We know that the rear portion of our brain gets pretty active during REM sleep, when most dreaming occurs. Some think that it's just the brain winding down for the night and that dreams are random and meaningless firings of the brain that we don't have when we're awake. The truth is, as long as the brain remains such a mystery, we probably won't be able to pinpoint with absolute certainty exactly why we dream.