DÉJÀ VU gives us the feeling we have experienced an event before, even though this may seem to be an impossibility. Thus, the feeling of familiarity accompanying déjà vu is often unexpected and inexplicable, leading many people to wonder if their déjà vu experiences are psychic, physiological, or both.
A number of mechanisms have been advanced to account for the déjà vu experience. Because psychic experiences of many kinds have been associated with déjà vu, it has often been suggested that déjà vu itself is a psychic experience. In this regard, déjà vu has been reported to be the result of reincarnation memories, subconscious memories of dream projections or out-of-body –experiences, subconscious memories of precognitive dreams, and clairvoyance. A higher frequency of déjà vu experiences have been reported for those who meditate frequently.
Another proposed mechanism for déjà vu is that of biochemically encoded ancestral memories. This concept states that memories build up over generations into instincts, race memories, the collective unconscious, and all the materials that make up the totality of mind. Such a theory of memory, both personal and inherited, was advanced by C.G. Jung as a explanation for déjà vu. According to Jung, whenever an external event touches upon some subconscious knowledge, this knowledge can reach our objective consciousness. “The event is realized as déjà vu, and one remembers a pre-existent knowledge about it.”
While the puzzling phenomenon of déjà vu has been reported in nearly all categories of altered states of consciousness, brain stimulation also achieves similar effects. Only a half-second’s stimulation in the hippocampal and amygdala portions of the limbic system. Lying deep within the brain’s temporal lobe, promotes déjà vu or familiarity as it is called by some researchers. Dr. Jose Delgado of Yale University noticed that patients stimulated in certain regions of the limbic system would listen to subsequent exchanges between themselves and the doctor with an air of amusement and bewilderment. “But this has all happened before. I knew what you were going to say before you said it.”
Patients with temporal lobe epilepsy who frequently experience déjà vu are more likely to have lesions in the right temporal lobe. Coincidentally perhaps, the right hemisphere is non-verbal, and more intuitive and artistic than the left hemisphere.
J.E. Orme of Middlewood Hospital in Sheffield, England, discussed the relationship of déjà vu to time theory in his scholarly work, Time, Experience and Behavior. He cited the work of R. Elfron, who found that the brain hemispheres do not necessarily process a message simultaneously. In a right-handed subject, a stimulus delivered to the left hand of the body is not available to the left hemisphere for two to six milliseconds after the right hemisphere receives the signal from the left side of the body. During the delay, the left hemisphere is unable to verbalize the sensation. The delay is the time it takes for the information to be passed to the talkative left hemisphere. If a lesion were to further delay the transfer, Elfron felt that maybe everything would appear to be happening twice, like instant replay.
This speculation falls short of accounting for the subjective feeling that one is recalling the distant past. Also, the déjà phenomenon is sometimes accompanied by a wave of ineffable poignancy; the memory seems to be set in an emotional context. The psychic nature of déjà vu often leaves one feeling of wonder. This unique sense of wonder accompanied by familiarity is a hallmark of the mystical experience, and thus, the increased incidence of déjà vu frequently reported for meditators is not unexpected. During such mystical experiences déjà vu may also be accompanied by specific memories of precognitive dreams and visions. In these instances the specific dream memory may be of a metaphoric or symbolic character. For instance, one subject in our laboratory reported dreaming of a recently deceased pet who transformed into another personality that was not recognized by the dreamer at that moment. But soon afterwards, when a close friend with identical features to those of the dream personality unexpectedly died, the laboratory subject experienced déjà vu. He came to realize that the dream was helpful to others as well as himself, for the dream served to prepare them comfort during subsequent events.
The brain mechanisms, while essential for the realization of such experiences as déjà vu, reflect a psychic process that lies deeper than the brain itself. The value of brain mechanisms, however, is that they allow us the opportunity to reflect more deeply upon the true nature of self