Robert Todd Carroll
Dreams are mental activities occurring during sleep. Most dreams occur in conjunction with rapid eye movements; hence, they are said to occur during REM-sleep, a period typically taking up 20-25% of sleep time. Infants are believed to dream during about 50% of their sleep time. Dreams occurring during non-REM periods are said to occur during NREM-sleep.
Sleep researchers divide up sleep time into stages, mainly defined by the electrical activity of cortical neurons represented as brain waves by an electroencephalograph (EEG). The EEG records electrical activity in the brain by connecting surface electrodes to the scalp. The stages of sleep occur in sequence and then go backward to stage 1 and REM-sleep about 90 minutes later. This cycle recurs throughout the night with the REM period typically getting longer at each recurrence. Typically, a person will have four or five REM periods a night, ranging from 5 to 45 minutes each in duration. There is some evidence, however, that REM-sleep evolved before dreaming and that the two are independent of one another.1
The REM-dream state is a neurologically and physiologically active state. When a person is in deep sleep there is no dreaming and the waves (called delta waves) come at a high amplitude about 3 per second. In REM-sleep, the waves come at a rate of about 60-70 per second and the brain generates about five times as much electricity as when awake. Blood pressure, heart rate, breathing rate, etc. can change dramatically during REM-sleep. Since there is generally no external physical cause of these states, the stimuli must be internal, i.e., in the brain, or external and non-physical. The latter explanation--that dreams are a gateway to a paranormal or supernatural realm--seems to be largely without merit, although it is very ancient. Each of the following may have contributed to this misconception: dreams of dead persons, dreams of being in distant places or of traveling back or forth in time, dreams that seem prophetic, and dreams that are so strange, curious or bizarre that they call out for a paranormal interpretation.
Nowadays, hardly anyone believes that dreams are messages from the gods. But some parapsychologists, such as Charles Tart, believe that dreams offer entry into another universe, a paranormal universe of OBEs, cosmic messages, and blissful nirvana. His main evidence for this seems to be his personal faith and an anecdote about his baby sitter. He claims the unnamed baby sitter (he calls her "Miss Z") had the power to leave her body during sleep. He claims he tested his flying babysitter in his sleep lab at UC Davis after she told him that she "thought everyone went to sleep, woke up in the night, floated up near the ceiling for a while, then went back to sleep." Other psychologists might have been concerned for the mental well-being of "Miss Z" and the safety of his or her children. Tart was intrigued. He put a number on a shelf, hooked up "Miss Z" to an EEG machine and put her to bed. She claims that even though she didn't read the number on the shelf, she flew around the room the first few nights. She didn't get the number right until the fourth night. Skeptics think either Tart is making up the story or it took the girl four nights to figure out how to trick the scientist. One will search in vain, however, for either a scientific paper on this alleged incident or for any further testing to try to duplicate the event. Others, however, have investigated the question of whether the mind is open to telepathic input during sleep and have failed to find evidence of psychic ability while dreaming. Scientific research by psychiatrist Montague Ullman and parapsychologist Charles Honorton in the early 1970s at Maimonides Hospital in Brooklyn, New York, obtained chance results after an initial testing that looked positive for psi (Baker).
Tart and other parapsychologists who think that the dream state is a gateway to another world2 seem to think that the key scientific evidence for this is the distinct brain waves of the various stages of sleep. They seem to think that brain waves represent states of consciousness and that sleep is an altered state of consciousness. However, sleep is not a state of consciousness, but unconsciousness. Furthermore, brain waves represent not states of consciousness but electrical activity in the brain. Brain activity during dream-sleep is indeed curious. While dreaming, not only do we experience the equivalent of hallucinations, some of which would qualify as psychotic if we had them while awake, most of us feel like we are physically moving, acting and being acted upon, without the body actually moving. Brain stem mechanisms protect us during sleep from motor activities that could lead to self-injury or injury to others. That is, most of us are paralyzed during sleep. However, some people suffer a weakness or disruption of the brain stem that causes a sleep disorder where motor activities are not prevented. People who suffer from this disorder flail, sleepwalk, etc., and can be a danger to themselves or others. Such people do not leave their bodies, but they often leave their beds during sleep.
Another curious quality of brain activity during dreaming is that almost all dreams are forgotten. Dream amnesia is the norm. This is not due to anything paranormal or supernatural, but to weak encoding. Memory depends upon encoding the data of experience. Encoding depends upon connections in parts of the brain, which in turn depend upon connections in experience. An event with a strong emotional component is more likely to be remembered than one with no emotional component because emotional memories are recorded in one part of the brain while visual components are recorded in another. Neural connections link them. We are likely to remember dreams if we wake shortly after they occur. Even so, if we do not encode the dream by making some effort to remember it, we are likely to forget it. Some people assist memory by getting up and writing down the dream. Others find that an easier method is to stay in bed and create some associations. The easiest association is made by giving the dream a title and a purposive description. For example, a dream of being chased by a polar bear across the snow into a library might be labeled "Research the Polar Bear." Go back to sleep and you are likely to remember the dream by recalling the title.
Perhaps the most curious quality of dreams is that most of us most of the time are not aware that we are dreaming while we are dreaming. PET scans during dreaming have shown that there is reduced activity in the prefrontal cortex during REM-sleep and this might account for several features of the dream-state.
Some researchers cite the lack of prefrontal activity as a sign that the function of sleep is restorative. Sleep gives a rest to the frontal lobes, the most active part of the brain while awake.4 And, it may well be that lucid dreaming--being aware of dreaming while dreaming--is possible for some people because their frontal lobes don't completely shut down during dreaming. Most parapsychologists, however, are not interested in the physiology of dreaming. They focus instead on the content of dreams, which they believe reveals a passage to the paranormal or the supernatural.
The prophetic or clairvoyant dream is perhaps the strongest reason for believing that dreaming is a gateway to another world. Some dreams seem uncanny. They seem to foretell events. If a significant number of dreams of just a single person corresponded to future events, this would be a great benefit to humankind and we should try to find out what mechanism is at work here. However, no such person has yet been found. Individual dreams that occasionally seem clairvoyant provide very weak evidence for clairvoyant dreams. I once had a very vivid dream of an airplane crashing nose first in San Diego (where I lived for 20 years). About ten years after the dream an airliner went down in San Diego. Am I clairvoyant? Would the case be stronger for clairvoyance if the airliner went down the day after I had my dream? I don't think so.
While it is admitted by most parapsychologists that some amount of coincidence is to be expected between what a person dreams and what actually happens, it is argued that there are too many cases of seemingly prophetic dreams to reasonably explain them all away as due to coincidence. It is true that not all prophetic dreams can be explained away as being due to coincidence. Most of them probably should be so understood, but many of them may be explained away as due to filling in memories of dreams after the facts and many others should be explained away as cases of lying. But the vast majority of prophetic dreams are probably coincidences. Such dreams are impressive to those who lack understanding of The Law of Truly Large Numbers, the Forer effect and how memory works. If the odds are a million to one that any given dream is truly prophetic, then, given the number of people on earth and the average number of dreams people have during each sleep period (250 dream themes a night, according to Hines, p. 50), we should expect that every single day of our lives there will be more than 1.5 million dreams that seem clairvoyant. That is not including all the dreams had by cats, dogs and other animals, who may well be having apparently psychic experiences while they sleep, though to what purpose we can only guess. Furthermore, one would think that if dreaming were a gateway to the paranormal or supernatural that blind persons would not have their dream time restricted by their physical limitations any more than those with sight. Yet, people blind from birth do not have visual dreams.5
There are also those who think that the dream-state is a gateway to past lives. There are some who even think that the dreams we have today are due to the fears our hunter-gatherer ancestors had. Universal dream themes, such as being chased or falling are said to hearken back to our hunter-gatherer days. We have these dreams because our ancestors were chased by saber-toothed tigers and slept in trees. The evidence for such beliefs is negligible, if not non-existent, although a strong case can be made that the form rather than the content of such dreams might well be due to an evolutionary development linked to exercising instinctive behavior necessary for survival.
If the dream-state is a gateway to anything, it is probably a gateway to current personal fears and desires, rather than to ancient ones of other people. We assume dreaming has a purpose, but that purpose is more likely to be rooted in this life than in some other one. Any decent theory of dreams must try to explain why the brain stimulates the memories and confabulations that it does. It is most likely that dreams are a result of electrical energy that stimulates memories located in various regions of the brain. Why the brain stimulates and confabulates just the memories it does remains a mystery, though there are several plausible explanations. Explanations in terms of the paranormal and supernatural are not as likely to have merit as those that limit themselves to biological and emotional mechanisms linked to brain activity.
One such hypothesis for sleep-related rhythms is that they are the brain's way of disconnecting the cortex from sensory input. When we are asleep, thalamic neurons prevent penetration of sensory information upward to the cortex.6 This gives the cortex a bit of a rest and explains why people who suffer sleep deprivation suffer a loss of critical thinking abilities and are prone to poor judgment. Another hypothesis is that dreaming plays a role in memory processing, especially with emotional memories. During REM-sleep, the amygdalas, which play a role in the formation and consolidation of memories of emotional experiences, are quite active.7 A related theory is that dreams are "watchdogs of the psyche" (Baker). Dreams are mechanisms that inform and guide our feelings and emotions. In short, this theory maintains that dreams are a way for us to express our desires and fears that, for whatever reason, need to be expressed but are not expressed when awake. If this is true, it would seem to follow that only one very intimate with the dreamer should attempt to interpret a particular dream. Dreams are very personal and speak to the specific emotional life of the dreamer. The "surest guide to the meaning of a dream is the feeling and judgment of the dreamer himself or herself, who, deep down inside, knows its real meaning" (Baker). This theory seems to be based upon the fact that most dreams are about things that have occurred within the past day or two and reflect the dreamer's present life and concerns, including unresolved feelings. This theory also implies that the interpretation of dreams can play a significant role in self-discovery; for, dreams reflect feelings and desires of which we are not conscious when awake. We may have anxieties or desires that only our dreams can reveal.
Most of us would have little difficulty in finding examples of "anxiety dreams" or "wish-fulfillment dreams" from our own experience. We may not have been aware of our desires or fears until they were awakened by the dream. Sometimes our symbolic dreams are so clear that we do not need outside assistance to help us interpret their meaning. Yet, many dreams are so strange, irrational or bizarre, that we are at a loss to find meaning in them. We seek others who claim expertise in dream interpretation to help us ferret out the hidden meanings of our dreams. Those who engage in the interpretation of dreams should be especially careful not to impose their own pet theories onto the dreams of others. For example, the dream mentioned above of being chased by a polar bear into a library might be interpreted in many different ways, but only I, my wife and one or two other persons familiar with the experience that that dream is rooted in are in a position to interpret it "correctly." I don't doubt that there are many possible interpretations and that some of them might seem quite plausible. But the "correct" one is one that has meaning for the dreamer. It was a frightening dream, just as the experience of dealing with a close relative with bipolar disorder (manic depression) was frightening. The experience led me to the library and to bookstores to get as much information about this brain disorder as I could. I have no doubt that a Freudian or Jungian could find some latent or symbolic meaning here that I do not note, but I have no interest in their interpretations because I have no way to check them against reality and do not share their assumptions regarding the psyche. I have no idea why my brain confabulated this dream, arousing fear and disturbing sleep. Reality is bad enough without having our brains arouse more fears during sleep.
There are some people, however, who have experienced much more horrible things than I have, who dream about them every single night of their lives (Sacks). Why the brain should terrify its owner by repeating horrifying memories during sleep seems beyond comprehension. Such obsessive dreaming is of no more value than obsessive-compulsive behavior. Such people don't just have nightmares; they are terrified to go to sleep. They need the help of a good therapist, but they are not in need of dream interpreter. If such dreamers are to be helped they must learn control their dreams. There are various method used to control dreaming, most of them involving visual or auditory preparations prior to sleep. Some therapists claim success with victims of recurrent nightmares by treating what is loosely called "post traumatic stress disorder." Some patients claim that they have been helped to overcome the experience of repetitious nightmares by lucid dreaming. None have been helped by treating dreams as a gateway to some higher realm of consciousness.
Alcock, James E. Science and Supernature: a Critical Appraisal of Parapsychology (Buffalo, N.Y.: Prometheus Books, 1990). $30.95
Asserinsky, E. & Kleitman, N. "Regularly occurring periods of ocular motility and concomitant phenomena during sleep," Science, 1953, 118: 361-375.
Baker, Robert. "Prophetic Dreams," in The Encyclopedia of the Paranormal edited by Gordon Stein (Buffalo, N.Y.: Prometheus Books, 1996) pp. 553-560. $104.96
Coren, Stanley. Sleep Thieves: An Eye-Opening Exploration into the Science and Mysteries of Sleep (The Free Press, 1997). $9.60
Farady, Ann. The Dream Game (New York: Washington Square Press, Pocket Books, 1985).
Hines, Terence. Pseudoscience and the Paranormal (Buffalo, NY: Prometheus Books, 1990). $19.16
Hobson, J. Allan. The Dreaming Brain; How the Brain Create Both the Sense and the Nonsense of Dreams (Basic Books, 1988). $20.00
Sacks, Oliver W. An anthropologist on Mars : seven paradoxical tales (New York : Knopf, 1995). $10.40
Schacter, Daniel L. Searching for Memory - the brain, the mind, and the past (New York: Basic Books, 1996). $11.20
Robert Todd Carroll
|Last updated 11/18/98|