mong some tribal groups in Borneo, dreams and waking reality are closely linked. One tradition holds that if a man dreams that his wife has been unfaithful, she must return to live with her father. In West Africa, as part of a coming-of-age ritual, teenage boys from the Bwiti cult drink tea made from the root of a local shrub. The potent brew induces a trancelike state during which the boy dreams a morality-laden account of his life--past, present, and future. • “It's a kind of ‘Equatorial Christmas Carol,’” says anthropology professor and chair Bryan Page. Here in the United States and in other Western societies, one common interpretation of dreams may seem equally fanciful: Dreams are windows into the subconscious mind--deeply symbolic tales that bring out one's hidden fears and anxieties. • These disparate beliefs, as useful as they are to their adherents, may illustrate how much we don't know about dreams. Despite advances in the neurosciences that allow us to peer inside the brain, measuring in detail the electrochemical activity that occurs while sleeping, the source and purpose of dreams remain as enigmatic to advanced Western cultures as they do to nonliterate or “primitive” ones. And in the absence of hard fact, customs persist and assumptions abound. • Perhaps the only common thread is humankind's endless conjecture on this age-old mystery: Why do we dream?

Some scholars, Page says, postulate that dreams are the origin of all religious and metaphysical thought. Long before organized religion, before the earliest traces of animism, before any recognition of higher consciousness, we dreamed. Their hallucinatory nature gave rise to the conception of the supernatural.

As civilization developed, explains Page, who also holds a professorship in psychiatry and behavioral science at the School of Medicine, dreams became associated closely with prophecy and divination. In both Western and Eastern traditions, dreams were thought to be messages from the supernatural world that could explain the causes of illness or famine, or to foretell the outcome of great events such as military battles. In the Old Testament, for example, Joseph gains favor with the Egyptian Pharaoh for his ability to decode dream symbols.

In the second century A.D., the Greek mystic Artemidorus Daldianus published the Oneirocritica, perhaps the most famous dream interpretation book of all time. By the seventh century A.D., dream divination was so entrenched in popular culture that Muhammad, the founder of Islam, is said to have banned the practice.

In the Middle Ages, the widely held belief that dreaming provided a link to the supernatural plane spawned a literary genre. In so-called dream allegory, or dream vision, the author uses a dream narrative to relay an allegorical tale. Geoffrey Chaucer's Book of the Duchesse and Guillaume de Lorris' Le Roman de la Rose are among the better-known examples. Literature, in fact, remained deeply influenced by the spiritual dimension of dreams up through the 19th century. Samuel Taylor Coleridge claims to have penned his poem Kubla Khan following an opium-induced dream. Other Romantic-era writers used dreams to create an altered state of being in which characters could transcend mortal consciousness.

ut that began to change in 1899. It was that year that psychiatrist Sigmund Freud published his landmark work The Interpretation of Dreams. Freud rejected the supernatural origin of dreams, arguing instead that they bubble up from the subconscious mind. Dreams, he believed, represent a person's deeply held wishes or fantasies, which are often sexual or aggressive in nature. Because these wishes could be painful to consider, even during sleep, they often took symbolic form. Wild animals, for example, signified lustful, passionate urges.

"Freud's principal position was that all human productions have meaning, and dreams are certainly among those productions," says associate professor of English Frank Stringfellow, whose specialty is literature and psychoanalytic theory. Freud's theory became the bedrock of psychoanalysis, the technique for treating mental disorder that emphasizes the disclosure of unconscious mental processes.

Freudian psychoanalytic theory profoundly influenced how Western cultures viewed the individual's relationship to the cosmic world. No longer were we left to the will of the gods or other spiritual influences. Our dreams, for better or worse, were our own creations. Early 20th-century art and literature reflected this new paradigm. Franz Kafka's The Metamorphosis, a story of a man who wakes up one morning to find himself a monstrous insect, is characteristic of literature's Expressionism movement of that time, which emphasized the deeper significance, rather than the outward appearance, of people and events.

In art, the influence of Freudian free association--a technique he often used in dream analysis--can be seen in works by surrealist artists such as Salvador Dali and Andre Breton.

While the impact of Freud is still broadly felt today within popular culture, his dream theory is no longer in vogue. Indeed, explains Stringfellow, Freud's writings are more likely to be taught within academia's English departments than they are in psychology departments.

n the 1950s, at a time when the theories of Carl Jung and other psychologists were supplanting Freud's, researchers began the first detailed physiological investigations of the brain during sleep. They discovered that dreams were most likely to occur during sleep stages known as rapid eye movement or REM. Studies revealed that REM, which occurs during about 25 percent of a nighttime sleep cycle, is controlled by a part of the brain called the pons. But the pons was discovered to control primitive functions such as breathing and reflexes. The more advanced parts of the brain--those that controlled emotions, memories, and symbolic messaging--were inactive during dreams. Freud, they concluded, must have been wrong. Dreams were seen as merely random images created by the incessant firing of the brain's neurons.

But advances in brain scanning techniques may reveal that the verdict on Freud's dream theory was premature. Bruce Nolan, associate professor of neurology and director of the Sleep Disorders Center at the School of Medicine, says new research indicates that other parts of the brain, including those that control higher emotional functioning, are indeed active during sleep. Studies also have revealed that dreaming occurs in sleep stages other than REM. While the new findings neither conclusively support nor reject Freud's theories, sleep researchers have been forced to rethink their concept of dreams.

Not surprisingly, the absence of a scientific explanation has led to a slew of hypotheses. One idea currently gaining favor is that dreaming is an evolutionary adaptation that allows us to rehearse survival behaviors by arousing our fears and anxieties. By dreaming about stressful situations (albeit imaginary ones), we're exercising our brains with the appropriate emotional response. Another idea is that dreaming allows our brain to continue working on the problems of waking moments, but without the clutter of life's external stimuli. This may account for the occasional reports of insights acquired while dreaming. A celebrated example is that of the 19th-century German chemist Friedrich August Kekule, who claimed that his discovery of the molecular structure of benzene came to him in a dream.

Nolan believes that dreaming is the brain's way of processing and organizing the vast amount of information it takes in each day. Why is it, he asks, that you can remember what you had for breakfast today but not three weeks ago? Dreaming is a means for sorting out the necessary from the superfluous. "The brain must continually make new associations, get rid of old ones, and reprogram the individual in a positive way," says Nolan.

Will we ever know, with certainty, the cause and meaning of dreams? Nolan is optimistic. "Sleep research has experienced tremendous breakthroughs in the latter half of the past century," he says. "My expectation is that even more startling discoveries will help to fill the wide gaps in what we currently don't know."

Decoding Dreams

or centuries philosophers have given symbolic meaning to the objects and concepts that appear in our dreams. Even today many mental health professionals routinely conduct dream analysis, occasionally using interpretive manuals to decode a dream's narrative tale.

Psychologist Kim Fuller, director of the University of Miami's Psychological Services Center, says such manuals can be helpful to "confirm hunches" but are far from authoritative. "These so-called dream dictionaries can be useful, but you really have to take them with a grain of salt," she cautions.

What do your dreams mean? Here is a sampling of objects and their symbolic representation as listed in The Dreamer's Dictionary by Lady Stearn Robinson and Tom Corbett: