Excerpted from Kelley Bulkeley‘s Where God and Science Meet. Click to download the pdf chapter on the Origin of Dreams.

Physiology of Sleep

For the past one hundred years, the main goal of Western scientific dream research has been to explain the form and content of dreams in terms of sleep physiology. Sigmund Freud developed the psychoanalytic model by which dreams were explained as “guardians of sleep” whose manifest content (i.e., the dream as remembered) is actually a deceptive mask enabling the secret, hallucinatory fulfillment of repressed instinctual desires. Beginning in the 1950s, Freud’s model was displaced by the discovery of rapid eye movement (REM) sleep and its connection to dreaming. Researchers found that human sleep (and indeed all mammalian sleep) is structured by automatic cycles of greater and lesser brain activation. This led to numerous investigations to identify correlations between the physiology of REM sleep and the psychological elements of dreams.

Disappointingly, the results of later studies did not fulfill the initial expectations. The movements of the eyes during REM sleep do not directly match or track what people are seeing in their dreams. Penile erections (and clitoral swelling) are automatic physiological accompaniments of sleep and do not always correspond to dreams of sexual imagery or arousal. No particular sleep-stimulus, whether a memory task, a physical activity, or watching a movie, has been shown to have a simple, direct impact on what people dream the subsequent night. More fundamentally, subsequent research demonstrated that dreams are no exclusively the province of REM sleep but are also reported with some frequency from NREM sleep (non-REM sleep). The more closely researches looked at actual dreams, the more they realized that REM physiology does not account for their basic features.

If nothing else, these findings indicate that pursuing a simplistic REM-dreaming isomorphism is a dead end for future scientific dream research. REM sleep may be a kind of triggering mechanism for most dreams, but the process of dreaming itself emerges from a complex, widely distributed system of brain-mind activities that are functionally independent of REM physiology. For now, the point is that the origins of dreaming are very clearly not in REM sleep.

A new scientific story of origins in needed, one that better accounts for current knowledge about the actual patterns of dreaming form and content.

Such a story will need to include an understanding of sleep physiology across REM and NREM stages. Indeed, there is no reason to believe that the artificial categories of REM and NREM are eternally valid, and we may hope that future researchers will find a better way to account for the complex, multidimensional sleep cycles of humans and other creatures. In the meantime, our stories of the origins of dreaming must include recognition of the strong and steady (if not absolute) relationship between the neurophysiology of REM sleep and the frequency and intensity of dreaming, while also acknowledging that genuine dreaming occurs outside of REM sleep. Our understanding of dreaming will always depend on our understanding of sleep in general, and future dream research will be most prosperous if it grounds itself in a more sophisticated foundation of knowledge about what’s happening in the approximately one-third of our lives we pass in slumber.

With this preliminary background in sleep physiology, the next step is to look more closely at the form and content of dreaming.

Psychology of Dreams

I focus not on dreams in general, but those relatively rare types of dreams that make a strong and lasting impact on the dreamer’s waking consciousness. If there is any function or value to dreaming, it is most likely to appear in those dreams that are remembered with greatest intensity, by the widest variety of people, from many different historical eras. The frequency of such dreams is increasingly well documented, and the Western psychological tradition has developed several important insights regarding their prototypical features. Drawing these insights together will provide a new basis for correlating dream psychology and sleep physiology, and this in turn will enable us to reassess the relationship between scientific and religious stories of the origins of dreaming.

Freud

The modern psychological study of dreams began with Sigmund Freud and the publication in 1899 of his monumental The Interpretation of Dreams. Freud’s psychoanalytic theory was created in large part through a probing investigation of his own dreams in the years following the death of his father. The central claim of his theory is that dreams are the disguised fulfillment of repressed wishes. To maintain healthy functioning of the mind, dreams serve as a kind of pressure valve, releasing pent-up instinctual energies in a safe and harmless fashion. The instinctual wishes that emerge are primarily egotistical and antisocial in nature, harkening back to infantile pleasure-seeking. Freud says an agency within the mind called “the dream-work” employs symbolic imagery and metaphorical language to fulfill the instinctual wishes without arousing moral anxiety, thereby allowing the individual’s sleep to continue undisturbed.

The psychoanalytic theory of dreams has attracted tremendous controversy over the past 100 years, and fortunately for our purposes we do not need to worry about the ongoing battles between Freud’s friends and foes. Taken as a comprehensive explanation of all features of dreams, Freud’s wish-fulfillment theory is certainly wrong. However, taken as an insight into vital (but not all-encompassing) features of human dream experience, Freud’s theory is certainly right: dreams frequently express instinctual wishes of an egotistical (especially sexual) nature, they do so by using a culturally saturated language of symbol and metaphor, and they contribute to healthy functioning of mind and body. Freud had very little to say about highly memorable dreams per se. Indeed, he believed dreams were meant to be forgotten, the better to hide their disturbing instinctual core, and so he was not inclined to pay much attention to those rare dreams that for some reason or another can’t be forgotten. But these three points — the role of instinctual desires, the language of symbol and metaphor, and the positive psychological function — are directly relevant to our contemporary understanding of prototypical human dreaming.

Jung

Carl Jung dates his fascination with dreaming to the earliest remembered dream from his childhood, in which he descends to an underground throne room and confronts a massive phallus on a throne. Jung was one of Freud’s earliest and most enthusiastic followers, but after the angry break-up of their relationship Jung withdrew into professional and personal isolation, surrendering to an upsurge of fantasy material from his unconscious. Building on these numinous, life-altering experiences, Jung developed a theoretical synthesis of clinical psychiatry and comparative mythology that explained dreams as natural (i.e. undisguised) expressions of the psyche whose function, even in the case of intensely frightening nightmares, is to promote the ultimate goal of individuation. Dreaming, Jung says, has the beneficial functions of compensating for the imbalances of the conscious mind and anticipating future challenges and developments in life. The classic themes, motifs, and symbols of world mythology provide the inherited mental language for oneirological expression. For Jung, dreaming is not simply a matter of animal instinct but also of spiritual enlightenment. This is especially true with what he calls “big dreams,” intensely vivid and memorable dreams that “are often remembered for a lifetime, and not infrequently prove to be the richest jewel in the treasure-house of psychic experience.”

As with Freudian psychoanalysis, Jung’s theory is questionable if taken in absolute terms. Whether we accept the entirety of his psychological system, several of his key points remain legitimate and important: the “naturalness” of remembered dreaming, the potential psychological value of nightmares, the symbolic interplay between dreaming and mythology, and, most crucially for our purposes, the recognition of various types of extraordinary “big dreams.”  Jung realized, in a way Freud never did, that certain dreams are different from others, with recurrent images, themes, and feelings that deserve careful investigation in their own right. Jung’s case studies may be open to debate as sources of evidence, but his key insight into the significance of highly memorable dreams has been strongly supported by subsequent research.