As long as we have been dreamers, we have longed for the answer to this question. In ancient times, dreams were treated as prophecy, portents, and divine inspiration. Some believe they provide a view into our subconscious or are a tool our brain uses to sort and process our experiences. But the truth is, even with the most modern technology, we simply don’t yet know why we dream.
There are several modern day theories that seek to explain what happens when our eyes close and our bodies go still. Each theory is rooted in science but relies on assumptions and leaps of faith to fill in the gaps. Sleep science has advanced by leaps and bounds in the last 60 years and continues to expand with the use of modern technology. It may not be long before we have a scientific basis with which to answer that question. Until then, however, here are the most popular modern day theories on why we dream.
The Evolutionary Theory
The basis of the evolutionary theory is that we use dreams to help us practice how we would respond to threatening situations. Many dreams include situations that are uncomfortable, frightening, and even dangerous to us personally. You are standing at the head of the class in your underwear. You are falling off a cliff or being chased by a hidden enemy. Scientists have found that the part of our brain that is responsible for triggering the fight or flight reaction is more active during REM sleep as is the part of our brains responsible for motor activity. They theorize that these types of dreams provide a safe space to practice real world responses.
The Memory Card Theory
If you have ever plugged your camera’ memory card into your computer and transferred all the files from the camera to the computer, you already understand this theory of why we dream. Those in this camp see dreams as a way for our brain to sort through all the images, memories, knowledge, and experiences of the day so that they can be filed away, stored, or discarded. This theory is supported by behaviors observed in rats whose brains seem to repeat the same patterns during REM sleep that they exhibited during the day. In essence, dreams keep our brains from overflowing with information.
The Defrag Theory
There is another school of thought that believes dreaming is like defragging our internal hard drive. When you run a defragmenting program on your hard drive, it cleans up and consolidates the information stored there to streamline the system and make more space available. According to this theory, dreaming is our brains way of discarding useless or broken connections, making new connections, and basically keeping everything streamlined.
The Therapist Theory
The fourth theory centers on the dream state as therapist. Those in this camp believe that we use dreams to confront difficult emotions, to process experiences, and to work through our internal drama in a place that is safe. It is kind of like our own internal mobile therapist couch.