Dreaming is the subjective experience of imaginary images, sounds/voices, words, thoughts or sensations during sleep, usually involuntarily. The scientific discipline of dream research is oneirology. Dreaming is associated with rapid eye movement (REM) sleep, a lighter form of sleep that occurs during the later portion of the sleep cycle, characterized by rapid horizontal eye movements, stimulation of the pons, increased respiratory and heart rate, and temporary paralysis of the body. It can also occur in other phases of sleep, though this is less common. Hypnogogia, which occurs spontaneously during the approach to deep sleep, is thought to be related to dreaming.
Dreams are a language of imagery. This imagery ranges from the normal to the surreal; in fact, dreams often provoke artistic and other forms of inspiration. Forms of dream include the frightening or upsetting nightmare and erotic dreams with sexual images and nocturnal emission.
Most scientists believe that dreams occur in all humans with about equal frequency per amount of sleep. Therefore, if individuals feel that they did not dream or that they only had one dream in any given night, it is because their memory of the dream has faded. This "memory erasure" aspect of the dream state is mostly found when a person naturally awakes via a smooth transition from REM sleep through delta sleep to the awake state. If a person is awoken directly from REM sleep (e.g. by an alarm clock), they are much more likely to remember the dream from that REM cycle (although it's most likely that not all dreams will be remembered because they occur in REM cycles, which are interrupted by periods of delta sleep which in turn have a tendency to cause the memory of previous dreams to fade.)
True dreaming has only been positively confirmed in Homo sapiens, but many believe that dreaming occurs in other animals as well. Animals certainly undergo REM sleep, but their subjective experience is difficult to determine. The animal with the longest average periods of REM sleep is the armadillo. It would appear that mammals are the only, or at least most frequent, dreamers in nature, which is perhaps related to their sleep patterns.
Neurology of dreams
There are two competing stories as to the neurological cause of the dreaming experience. The state of REM sleep is known to be produced by a brain region known as the pons. The activation-synthesis theory states that the brain tries to interpret random impulses from the pons as sensory input, producing the vivid hallucinations we know as dreams. Sensory-based input interpretation is in turn based on past experience. Perhaps this is the reason why our dreams contain many characters and scenes from our regular lives. For some people, there are dreams that recur again and again over many years, sometimes with new additions derived from new experiences during waking life.
However, research by Mark Solms seems to suggest that dreams are generated in the forebrain, and that REM sleep and dreaming are two different brain systems. The debate between these two theories is ongoing.
Supernatural interpretation of dreams
Oneiromancy is the art of divination by interpreting dreams.
- Main article: Lucid dreaming
Lucid dreaming researchers often define lucid dreaming as simply "being aware in a dream that one is dreaming". Many others define a lucid dream as a dream in which the dreamer has full awareness that the situation he is in is a construct of his mind, and thus can analyse the situation logically and react accordingly. Such full awareness adds numerous extra abilities to the dreamer. The dreamer usually has control of the direction of the dream and can thus explore the dream world. This control is particularly helpful during nightmares, when the dream self can turn round and face the attacker to confront or destroy it. When lucid, the dreamer usually has direct control of the dream environment, and hence can do things impossible in real life, such as making new objects appear, polymorphing, or flying. Lucid dreams can occur spontaneously, especially during youth, but for lucid dreams to occur more frequently, dedication and practice is almost always necessary.
Lucid dreams can be categorized into Dream-Initiated Lucid Dreams (DILDs) and Wake-Initiated Lucid Dreams (WILDs). DILDs start as non-lucid dreams, but at some point in the dream the dreamer realizes they're dreaming. In a WILD, conscious logic and reasoning is preserved while the dreamer transitions from waking to dreaming, and the dreamer is lucid from the beginning of the dream. These uses of "WILD" and "DILD" have mostly fallen into disuse (or rather they mostly never came into use), though "WILD" is often used to refer to any technique in general that happens to induce a wake-initiated lucid dream, by moving directly from conscious wakefulness to conscious dreaming.
Lucid dreamers are those who practice lucid dreaming frequently for personal or spiritual gain. They usually induce lucid dreams through the use of one of many induction techniques. A common technique, known as MILD (Mnemonic Induction of Lucid Dreams) and developed by Stephen LaBerge, consists of remembering to recognize that they are dreaming the next time they have a dream.
Books on Dreams
- Artemidorus, The Oneirocritica of Artemidorus, University Microfilms, New Haven (1971).
- Gerolamo Cardano, Sul sonno e sul sognare , Marsilio, Venezia (1989).
- Carlos Castaneda, The Art of Dreaming, Rayo, (1994).
- Jayne Gackenbach , Stephen LaBerge, Conscious Mind, Sleeping Brain: Perspectives on Lucid Dreaming, Plenum Publishing Corporation, New York (1988).
- Carl Gustav Jung, Dreams, Princeton University Press, Princeton (1974).
- Namkhai Norbu Rinpoche , Dream Yoga and the Practice of Natural Light, Snow Lion Publications, Ithaca, New York (1992).
- Sigmund Freud, The Interpretation of Dreams , Avon, (1980).
- Tenzin Wangyal Rinpoche, The Tibetan Yogas of Dream and Sleep, Snow Lion Publications, Ithaca, New York (1998).