Theories attempting to explain the origin and functions of REM sleep include: (1) that
REM sleep provides stimulation for the development of the brain; (2) that it performs a chemical
restoration function, since during REM dreaming neuro-protein synthesis occurs along with the
restoration of other depleted brain chemicals; (3) that it provides oculomotor (eye movement)
coordination, since during non-REM sleep the eyes move independently of each other; (4) that it
provides a vigilance function, since REM sleep (stage I) is characterized by a level of
consciousness close to the awakened state; (5) in a more recent and controversial theory, REM
dreaming performs a neurological erasure function, eliminating extraneous information build-up in
the memory system; and (6) that, in a more cognitive psychological explanation, REM dreaming
enhances memory storage and reorganization.
Contrary to popular belief, dreaming is not caused by eating certain foods before
bedtime, nor by environmental stimuli during sleeping.
Dreaming is caused by internal biological
process. Some researchers have proposed the activation-synthesis hypothesis. Their
neurological research indicates that large brain cells in the primitive brain stem spontaneously fire
about every 90 minutes, sending random stimuli to cortical areas of the BRAIN. As a
consequence, memory, sensory, muscle-control, and cognitive areas of the brain are randomly
stimulated, resulting in the higher cortical brain attempting to make some sense of it. This,
according to the research, gives rise to the experience of a dream.
Now, as in the past, the most significant controversy centers on the question of whether dreams
have intentional, or actual personal, meaning. Many psychotherapists maintain that while the
neurological impulses from the brain stem may activate the dreaming process, the content or
meaningful representations in dreams are caused by nonconscious needs, wishes, desires, and
everyday concerns of the dreamer. Thus, such psychotherapists subscribe to the
phenomenological-clinical, or 'top-down,' explanation, which holds that dreams are intentionally
meaningful messages from the unconscious. The neurological, or 'bottom-up,' explanation
maintains that dreams have no intentional meaning. In between these two positions is an
approach called content analysis. Content analysis simply describes and classifies the various
representations in dreams, such as people, houses, cars, trees, animals, and color, though no
deep interpretation is attributed to the content. Differences in content have been discovered
between the dreams of males and females, and between dreams and occurring in different
developmental stages of life. What these differences mean is under investigation.
Some recent research seems to indicate that dream content reflects problems that the
dreamer experiences in life, and that the function of such dreams is to facilitate the emotional
resolution of the problems. Numerous accounts exist of scientific problems being resolved, and
literary works being developed in dreams after dreamers had consciously immersed themselves in
a problem for an extended time.
Cognitive psychologists are concerned with logic and thought processing during
dreaming, and how they are different from mental processes during the waking state. In studies
of the developmental cognitive processes of children's dreams, for instance, it has been found
that the increasing complexity of children's dreams parallel waking cognitive development. Many
researchers believe that knowledge about dreaming is important for understanding waking
Current and future research issues involve further establishing and extending all of the
above areas. Anthropologists are studying cross-culture similarities and differences in dreams.
Research into NIGHTMARES and bizarre dreams continues. In addition, REM research is
important for understanding psychobiological abnormalities. Some findings indicate that epileptic
seizures are suppressed during REM sleep. Narcoleptics, people who may involuntarily fall asleep
at any time, enter REM sleep almost immediately. Research continues on the variations in dream
recall. For instance, artists tend to recall more dreams than scientists, and, for the population at
large, only a small percentage of dreams are recalled.
Lucid dreaming, the ability of dreamers to become aware of and to control their dreams while
dreaming, is also the focus of some current research. Some lucid dreamers can learn to
communicate with researchers through nonverbal signals. New research also promises to yield
significant knowledge about memory, storage and retrieval, cognitive organization,
psychobiological processes, human consciousness, and specific operations of the mind