Why Do We Dream?

Paige Safyer

Biology 103

Why Do We Dream?

Over the years there have been many theories about why we dream, both neurological and psychological (2) but no one theory has fully explained this universal phenomenon (1). Everyone dreams (3), whether we are able to remember our dreams or not, and we all have our own beliefs about their importance. A person recounting their dreams is a commonplace activity. Some of us look for messages and meaning within our dreams, and many books about dream interpretation line the shelves of bookstores everywhere. There are also many theories about the neurobiological processes of dreaming (2), and as we begin to understand more and more about these processes we come closer to understanding their function.

We spend around 25% of our sleeping hours in REM sleep, which is the deepest form of sleep. This type of sleep occurs every 90-100 minutes alternating with the four other types of sleep. Together these four other types of sleep are known as NREM sleep. Sleep experiments have shown that in most cases of REM sleep dreaming occurs, while dreams only occur in NREM in a small percentage (4).

Because of the high correlation between REM sleep and dreaming conclusions were drawn that the same brain mechanisms that control REM sleep also control dreaming (3). In recent years, however, new experiments have shown that although there is a link between REM sleep and dreaming they are independent states and one can exist independently without the other. Evidence has suggested that dreaming is controlled by dopaminergic forebrain mechanisms while REM sleep is controlled by cholinergic brainstem mechanisms (4).

It has also been found that particular forebrain mechanisms are involved in the creation of dream content, which is actively created through complex cognitive processes. In other words, dreams may actually have meaning and importance. PET scans supporting this thought have found that the limbic and paralimbic regions of the brain are active while one is dreaming. These are areas that control emotion and motivation. Also, areas of the prefrontal cortex, which maintain working memory, attention, logic and self-monitoring, were inactive. These findings support the idea that dreaming is a higher mental function with meaning and importance behind it (4).

The idea that dreams are important is not a new one. Sigmund Freud, the father of psychoanalysis, believed that dreams were an attempt at wish fulfillment by the unconscious (5). Carl Jung, another famous psychiatrist believed that dreams were there own kind of language, and that their meanings could eventually be revealed through correct interpretation (2). Contemporary dream theory hypothesizes that dreams can help us cope with very intense emotions. If something traumatic happens to us, we may relive the emotions again through our dreams. In this way, dreaming helps us deal with our intense emotions and hopefully in the future we would be more equipped to deal with traumatic or stressful events. This may have been important to our ancestors, who experienced a lot more suffering in their lifetimes than we do in today’s westernized society (1).

Although the question of why we dream is far from being resolved, scientific and psychoanalytic theories have provided much to think about. As we’ve been learning in biology it seems that instead of finding definitive answers, science is more about discovering new questions. It seems to me that there are still many more questions waiting to be asked about the true nature of dreams.

Works Cited

1) http://www.sciam.com/askexpert_question.cfm?articleID=00072867-D925 1F0E-97AE80A84189EEDF

2) http://en.wikipedia.org/wiki/Dream

3) Hobson, J. A., Pace-Schott, E. F., & Stickgold, R. (2000). Dreaming and the brain: toward a cognitive neuroscience of conscious states. Behavioral and Brain Sciences, 23(6), 793-842

4) Solms, M. (2000). Dreaming and REM sleep are controlled by different brain mechanisms. Behavioral and Brain Sciences, 23(6), 843-850

5) http://en.wikipedia.org/wiki/The_Interpretation_of_Dreams