Dreaming: Three Theories

Dreaming: Three Theories


There is no doubt that sleep is vital to living a healthy life.  Not only is it key in maintaining a healthy lifestyle (in fact, those of us who are good about our sleep often have a healthier weight than those of us who struggle to sleep regularly), but it works wonders for your mental processes as well.  Although most scientists still debate the specific reason why sleep is so important, there are many theories that explain why we do it.  During sleep, the brain is shown to actually restore and replenish energy stores for the next day, in addition to strengthening your immune system.

Sleep is also believed to be adaptive, having evolved to tune out the external world when the threat of danger is at a minimum.  This explains why some animals sleep at night, others sleep during the day, and others sleep according to their own peculiar cycles.  Only a few animals, such as frogs, exhibit states that cannot technically be considered sleep.  Fun fact:  Dolphins have uni-hemispherical sleep patterns, meaning that their individual cerebral hemispheres take turns sleeping!

Sleep is also extremely important for facilitating learning.  Sleep strengthens neural connections, which are at the basis of learning.  Studies have shown that in memory testing, participants perform better having slept in between tests than those who did not.  Other studies have shown that during exam weeks, students experience an increased amount of REM sleep, supporting the idea that when a greater amount of mental consolidation is necessary, sleep, especially REM sleep, is vital to the brain and body.

So what exactly happens when we sleep?  Most people can answer this pretty easily:  Dreams happen when we sleep!   However, many people don’t know that there are in fact two different types of dreams, REM dreams, and non-REM dreams.  The defining difference is that while REM dreams are often characterized by very bizarre and surreal events, non-REM dreams generally involve dull and mundane events.  So, next time you wake up from a dream about folding your socks, you can be sure you were in the middle of non-REM sleep!

But what exactly are dreams? The theories to explain dreaming have many similarities to the theories that explain sleep.  The first theory is called the activation-synthesis theory.  This theory states that during sleep, random brain activity occurs.  These random neural firings then activate parts of the brain that would normally be interpreting sensory input.  As a result, your brain must find a way to make sense of this random brain activity by synthesizing it with previously stored memories.  Evidence against this theory states that if this were true, our dreams would actually be much more bizarre than they already are and share even fewer similarities with waking life.

The second theory results from the work in the field of psychoanalysis done by Sigmund Freud.  Freud presented the theories of manifest content and latent content.  According to his research, dreams actually contain messages that are generally hidden from conscious awareness but represent unconscious conflicts within the mind of the dreamer.    This theory can be broken down into two parts:  manifest content, which is how the dream actually manifests itself within the dreamer and how it is remembered once the dreamer wakes up, and latent content, which is what the dream symbolizes to the dreamer.  Although there is no real support for Freud’s theory, it does offer an interesting insight into the endless ways the brain may be working and also how it could be interpreted.

And finally, the evolved threat-rehearsal theory contests that similar to how we have adapted to sleep at night, we have also evolved to experience dreams that simulate life-threatening situations thereby allowing people to rehearse and also learn from the particular situation.  According to this theory, dreaming may in fact be a direct result of evolution.  Several facts support this theory, specifically that dreaming is associated with the amygdala which is activated by real dangers.

While sleeping and dreaming have yet to be definitively defined, they are indicative of the endless possibilities behind the mystery of the human brain, which is pretty cool!

Cheers and sleep well.