Ever since Freud first proposed that dreams were the ''royal road to the unconscious,'' it has been standard clinical practice to assume that dreams bear meaningful psychological messages, though often in bizarre disguise.
In recent years some researchers and neuroscientists, using new, sophisticated techniques for measuring brain activity during sleep, have attacked that understanding. They assert that dreams are essentially mental nonsense that have no psychological significance whatever. Their conclusions have provoked widespread argument in the field because they suggest that all therapeutic uses of dreams may be much less valid than had been thought. But already there are some signs of compromise.
Wherever the argument may ultimately lead, the new data and theories even now are prompting some clinicians to modify their understanding of the role of dreams in mental life.
In general, researchers divide sleep into two principal phases: rapid eye movement, or REM, sleep, and non-REM sleep. Dreams are associated with REM sleep
The body and brain are in a unique state during REM sleep. The eyes move back and forth under the closed lids, hence the name. Brain waves are in many ways similar to those during the waking state. At the same time, the major muscles of the body are in a kind of paralysis, so that they move little, if at all.
In sleep research, volunteers are monitored for eye movements, brain waves and other biological functions during the night. To investigate dreaming, the volunteers are awakened when these indicators signal REM sleep. About 80 percent of the time a sleeper awakened from REM will report being in the middle of a dream. In the remaining cases, for the most part, the wakened subject will report some other mental activity, such as vague thoughts, but with no visual image or sense of a dream.
The classic Freudian view of dreams held that dreams are upsetting impulses that the mind has disguised.
''The psychological work done in dreams is to disguise these impulses so they won't be disturbing, and to keep the sleeper from waking,'' Dr. Morton Reiser, chairman of the Department of Psychiatry at Yale University and a former president of the American Psychoanalytic Association, explained in an interview. ''In a nightmare, the disguise is inadequate; the disturbing material breaks through and the person wakes up.''
''Dreams are useful in therapy,'' he added, ''because they harbor clues to the psychological issues and earlier conflicts in a person's life.''
Although Dr. Reiser takes a psychoanalytic view toward dreams, he is one of those who is able to reconcile it with the new brain research.
Within the school that places great value on dreams, there are many approaches to finding the psychological message of a dream, each reflecting different theoretical outlooks. A Freudian will find one kind of meaning in a dream, while a Jungian will find another, and a Gestalt therapist will find still another meaning. But all would agree that there is meaning to be found, even if they may disagree as to exactly what that meaning might be. And many say each and every element of a dream - a given image or sensation, say - has significance.
But the view that dreams have psychological meaning at all has come under strong attack from neuroscientists.
Strong Attack on Theory One of the strongest attacks comes from a theory published last year in the journal Nature by Francis Crick of the Salk Institute in La Jolla, Calif., and Graeme Mitchison of Cambridge University. Dr. Crick, who won a Nobel Prize as the co-discoverer of DNA, has turned his attention to brain research.
Dr. Crick and Dr. Mitchison propose that REM sleep is the occasion for the brain to eliminate mental activity that might interfere with rational thought and memory. Their view holds that during a day the brain makes many more connections between brain cells than are needed for efficient thinking and memory.
The function of dreams, they say, is to ''unlearn'' or purge the brain of these unneeded connections. According to this view, what goes through the mind during a dream is merely the result of a sort of neural housecleaning.
This theory, they say, explains some facts about dreams that the opposing view cannot. For example, newborn infants have a great deal of REM sleep, but presumably suffer none of the psychological conflicts or upsetting impulses that Freudian theory says leads to dreams. But, Dr. Crick and Dr. Mitchison say, infants have the same need as adults to rid the brain of accidental or meaningless connections, and thus they have dreams.
The implications of the Crick- Mitchison theory goes beyond dream meaning. They say it also suggests that it may be damaging to recall one's dreams because doing so might strengthen neural connections that should be discarded. Most dreams, Dr. Crick and Dr. Mitchison note, are never remembered. In their view, this is as it should be. ''We dream in order to forget,'' they write. A different view with similar implications has been offered by Christopher Evans in his book ''Landscapes of the Night: How and Why We Dream,'' published posthumously by Viking this month. His theory also implies that dreams do not have the psychological meanings that therapists find in them, but Dr. Evans comes to his conclusion on a different basis than that of Dr. Crick and Dr. Mitchison.
Dr. Evans, a psychologist and computer scientist, proposes that dreams are the brain's equivalent of a computer's inspection of its programs, allowing a chance to integrate the experiences of the day with the memories already stored in the brain. His theory is based in part on evidence that dreaming consolidates learning and memory.
The contents of a dream, according to Dr. Evans, are fragments of events and experiences during the day which are being patched into related previous memories. ''Dreaming,'' he writes, ''might be our biological equivalent to the computer's process of program inspection.''
Such conclusions have been challenged by the work of two researchers at Harvard Medical School, Robert McCarley and J. Allan Hobson. Studies of the brain, they say, show that there is a ''dream state generator'' that repeatedly stimulates the cortex during REM sleep. This ''generator,'' located in the brainstem - specifically in the so-called giant pontine cells of the reticular formation - sends random signals to higher brain centers that control such functions as vision, hearing, balance, movement and emotions, the researchers say.
Random Activity in Brain
The contents of a dream, the theory holds, are the product of this random activity, which the higher brain centers try to weave into a coherent story, just as is done with experiences during waking life.
Dr. McCarley and Dr. Hobson see their theory as contradicting the Freudian view that dreams are psychological in origin, being caused by unfulfilled impulses arising from psychological conflicts. The bizarreness of dreams, they say, is not a disguise for such conflicts, but simply reflects the random nature of brain activity caused by the dream generator.
''Dreams are like a Rorschach inkblot,'' Dr. Hobson said in an interview. ''They are ambiguous stimuli which can be interpreted in any way a therapist is predisposed to. But their meaning is in the eye of the beholder - not in the dream itself.'' That idea, it can be argued, is borne out by clinical examples collected by others that show how different therapists interpret the same dream differently.
Dr. Hobson has engaged in a series of public debates with psychoanalysts in which he challenged the view that dreams have psychological meaning.
Dr. Reiser of Yale is one of those who has debated Dr. Hobson. ''McCarley and Hobson overextend the implications of their work when they say it shows that dreams have no meaning,'' he said. ''I agree with them that their work refutes Freud's idea that a dream is instigated by a disguised wish. Knowing what we do now of brain physiology, we can no longer say that.''
''The wish may not cause the dream,'' he added, ''but that does not mean that dreams do not disguise wishes. The brain activity which causes dreams offers a means whereby a conflicted wish can give rise to a particular dream. In other words, wishes exploit - but do not cause - dreams.'' Dr. Reiser's view stems from a growing body of evidence that seems to show that dreams serve a major role in psychological life.
Typical of this line of research is the work of Rosalind Cartwright, a psychologist at Rush-Presbyterian- St. Lukes Medical Center in Chicago. In an article to appear next month in the journal Psychiatry, Dr. Cartwright presents findings suggesting that dreams are connected with adjustment to major life crises, in this case divorce.
Dreams of Women Explored
Dr. Cartwright compared the dreams of women who were recently divorced and also depressed with two other groups, one made up of women who had just been divorced but showed no signs of depression, and the other consisting of married women who said they were not contemplating divorce.
She found that the depressed women had an unusual pattern of REM sleep, including an earlier onset, longer duration and more intensely visual first REM period of the night, ''as if these patients can't wait to dream.''
Of more significance psychologically, though, is what the different groups of women dreamed about. The depressed women, in Dr. Cartwright's view, rarely dealt with marital issues in their dreams. And while those divorced women who were not depressed frequently dreamed of themselves in the role of wife or former wife, the depressed women almost never appeared in those roles in any of their dreams.
The divorced women who were not depressed had the most anxious dreams of all, with the level of anxiety in their dreams increasing as the night progressed. The identical pattern has been found in a group of patients judged successfully treated in psychotherapy.
The depressed women, who had less overall anxiety in their dreams, with anxiety decreasing over the course of the night, duplicated the pattern of psychotherapy patients who failed to improve.
These results, in Dr. Cartwright's view, support the view that dreams are ''safety valves,'' allowing the dreamer to deal with upsetting psychological issues.
A blend of the seemingly opposing views that, on one hand, dreams are composed of random elements, and that, on the other, they hold psychological meaning, has recently been proposed by Martin Seligman, a psychologist at the University of Pennsylvania.
Building on the work of Dr. McCarley and Dr. Hobson, Dr. Seligman accepts that the stuff of dreams consists largely of random visual hallucinations and unrelated feelings activated by the brain's dream generator. But, Dr. Seligman says, these random elements are woven into a meaningful fabric by cognitive activity that goes on continuously, day and night.
Indeed, sleep researchers have found that when people are awakened during non-REM sleep, they still report having thoughts, but not dreams.
A Stream of Thought
According to Dr. Seligman, this stream of thought operates much the same during the night as it does during the day. ''In my research, subjects who were asked to tell a story about random slides constructed plots similar in form to their dreams. For example, people whose dreams were tightly knit constructed tightly knit stories about the slides,'' Dr. Seligman said in an interview. Dr. Seligman's theory holds room for both camps. The raw stuff of dreams may be random, but ''subconscious motivation may influence the way we integrate the elements of a dream,'' he said.
Many clinicians, familiar with the debate over dreams, agreed in general with Dr. Seligman's proposal, although they differed over particulars. ''There are vastly more elements - images, ideas, actions and the like - in a dream than we can deal with in analysis,'' said Dr. Reiser. ''The way the dreamer connects those elements gives them their meaning. That's how the mind exploits the brain in a dream.''
''But there is lots of 'noise' in a dream,'' he added. ''When you find the signal - that is, the significance - in the dream, it leads you to issues in the person's life. Those parts of the dream we can't make sense of may be the random noise. Often what seems most obscure on the surface is what finally reveals a deeper meaning.''
''The therapist's art is finding the signal in the noise,'' he said
.
