What Causes Dreams?

Did you ever wonder what causes dreams? Dreams are an interesting phenomenon, and the topic of much debate. Do dreams reveal hidden desires, or are they merely a conglomerate of random thoughts? What is the purpose of dreaming, and does it provide some type of psychological benefit to us? There are many questions to consider about dreams, but first we must understand the cause behind them.

Dreams are a series of images, emotions, sounds, or thoughts that occur during a specific portion of when you sleep. Your sleep is divided into two main blocks: rapid eye movement sleep (known as REM), and non rapid eye movement sleep (Non-REM). Dreams almost always only occur during REM sleep.

REM Sleep

REM sleep is only a small part of your sleep, usually taking up only about twenty percent of our overall sleep. Your sleep cycle is broken up into different stages—the first four stages are Non-REM and include your deep sleep stages, and the last stage is REM sleep.

During any given night, you will usually go through the sleep cycle at least three or four times, which means that you will have three or four periods of REM sleep. For example, if you sleep for about seven hours, you will have a little over an hour of REM sleep.

During REM sleep, your breathing is irregular and your heart rate is irregular as well. Your electroencephalographic recordings are also much lower and more rapid—much more similar to the type of brain activity that you have when you’re awake. During Non-REM sleep, your breathing and heart rate is much more regular and much slower.

Although scientists still aren’t exactly sure what causes dreams, it’s clear that REM sleep is very important to human beings. In studies, when individuals were deprived of REM sleep over and over again, their memory and learning ability was extremely decreased the next day. Further, when they were allowed to go back to sleep, their body would attempt to go directly into REM sleep and bypass the other stages. REM sleep has been shown to be fundamental to human health.

Theories on Why Dreams Occur

Even though there’s agreement about what causes dreams, there have been a lot of different theories about the topic. The physiological theory about why dreams occur, for example, is that dreams replace the functioning of transmitting messages that ceases because our brain is not active during sleep.

Psychological Theories About Dreams

Alternatively, there have been a number of psychological theories about dreaming. Sigmund Freud proposed that dreams were a combination of our daily activities, and suppressed wishes. In fact, Freud felt that dreams were the key to understanding our subconscious thoughts and desires.

Alternatively, Carl Jung proposed the dreams were a combination of personal experience, as well as Jung’s “collective unconscious.” Jung’s collective unconscious was the idea that the entire world shares certain memories, and beliefs. Dreams, thus, tapped into that.

Another famous psychologist, Alfred Adler, believed that dreams were a problem solving device. The problems and questions that individuals were confronted with in their daily lives presented themselves again during sleep, and individuals continued to try to solve them.

Neorological Research

Neuroscientists have also started to tackle this question. For example, during REM dreaming, serotonin levels are very low and acetylcholine levels are extremely high. This chemically explains why you have trouble remembering your dreams when you wake up—they weren’t encoded in your short term memory. When your brain becomes “active” and you wake up, your serotonin levels rapidly rise again and this makes it difficult to remember your dreams.

One neuroscientist, Hobson, hypothesizes that the reason why dreams are often so strange is because when your brain is awake, it’s performing a series of reality checks and logic as you interact with the world. However, since the serotonin levels are down during REM sleep, you cannot perform this same reality checking. Your brain attempts to make sense out of the chaos, but is only able to do an inadequate job.