Understanding the Brain

Déjà vu

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Déjà vu (French pronunciation: [deʒa vy]Template:IPA audio link, literally "already seen") is the experience of feeling sure that one has already witnessed or experienced a current situation, even though the exact circumstances of the previous encounter are uncertain and were perhaps imagined. The term was coined by a French psychic researcher, Émile Boirac (1851–1917) in his book L'Avenir des sciences psychiques ("The Future of Psychic Sciences"), which expanded upon an essay he wrote while an undergraduate. The experience of déjà vu is usually accompanied by a compelling sense of familiarity, and also a sense of "eeriness", "strangeness", "weirdness", or what Sigmund Freud calls "the uncanny". The "previous" experience is most frequently attributed to a dream, although in some cases there is a firm sense that the experience has genuinely happened in the past.[1]

The experience of déjà vu seems to be quite common among adults and children alike. References to the experience of déjà vu are found in literature of the past,[2] indicating it is not a new phenomenon. It has been extremely difficult to invoke the déjà vu experience in laboratory settings, therefore making it a subject of few empirical studies. Certain researchers claim to have found ways to recreate this sensation using hypnosis.[3]

Scientific research

The most likely explanation of déjà vu is not that it is an act of "precognition" or "prophecy", but rather that it is an anomaly of memory, giving the false impression that an experience is "being recalled".[4][5] This explanation is substantiated by the fact that the sense of "recollection" at the time is strong in most cases, but that the circumstances of the "previous" experience (when, where, and how the earlier experience occurred) are quite uncertain or known to be impossible. Likewise, as time passes, subjects can exhibit a strong recollection of having the "unsettling" experience of déjà vu itself, but little or no recollection of the specifics of the event(s) or circumstance(s) they were "remembering" when they had the déjà vu experience. In particular, this may result from an overlap between the neurological systems responsible for short-term memory and those responsible for long-term memory (events which are perceived as being in the past). The events would be stored into memory before the conscious part of the brain even receives the information and processes it.

Another hypothesis being explored is that of vision. The hypothesis suggests that one eye may record what is seen fractionally faster than the other, creating the "strong recollection" sensation upon the "same" scene being viewed milliseconds later by the opposite eye.[6] However, this hypothesis fails to explain the phenomenon when other sensory inputs are involved, such as hearing or touch. If one, for instance, experiences déjà vu of someone slapping the fingers on his left hand, then the déjà vu feeling is certainly not due to his right hand experiencing the same sensation later than his left hand considering that his right hand would never receive the same sensory input. Also, people with only one eye still report experiencing déjà vu or déjà vécu (a rare disorder of memory, similar to persistent déjà vu). The global nature of the phenomenon can therefore at least in certain cases be narrowed down to the brain itself (i.e., one hemisphere being late compared to the other one).

Links with disorders

Early researchers tried to establish a link between déjà vu and serious psychopathology such as schizophrenia, anxiety, and dissociative identity disorder, with hopes of finding the experience of some diagnostic value. However, there does not seem to be any special association between déjà vu and schizophrenia or other psychiatric conditions.[3] The strongest pathological association of déjà vu is with temporal lobe epilepsy.[7][8] This correlation has led some researchers to speculate that the experience of déjà vu is possibly a neurological anomaly related to improper electrical discharge in the brain. As most people suffer a mild (i.e. non-pathological) epileptic episode regularly (e.g. a hypnagogic jerk, the sudden "jolt" that frequently, but not always, occurs just prior to falling asleep), it is conjectured that a similar (mild) neurological aberration occurs in the experience of déjà vu, resulting in an erroneous sensation of memory. For someone who regularly has such seizures, there is typically a feeling of déjà vu associated with whatever sensations (particularly sounds) may be occurring nearby.

Pharmacology

Certain drugs increase the chances of déjà vu occurring in the user. Some pharmaceutical drugs, when taken together, have also been implicated in the cause of déjà vu. Taiminen and Jääskeläinen (2001)[9] reported the case of an otherwise healthy male who started experiencing intense and recurrent sensations of déjà vu upon taking the drugs amantadine and phenylpropanolamine together to relieve flu symptoms. He found the experience so interesting that he completed the full course of his treatment and reported it to the psychologists to write up as a case study. Due to the dopaminergic action of the drugs and previous findings from electrode stimulation of the brain (e.g. Bancaud, Brunet-Bourgin, Chauvel, & Halgren, 1994).[10] Taiminen and Jääskeläinen speculate that déjà vu occurs as a result of hyperdopaminergic action in the mesial temporal areas of the brain. Many scientists are still working towards the actual link of déjà vu with hypnagogic epilepsy.

The sensation of uncannieness and dearth of tangible causality lead many to impart a supernatural component to déjà vu, however it is possible that there is a neurochemical basis to the phenomena. An endochemical that spurs the sensation of memory much like Epinephrine inspires the fight/flight response.
A bell curve of perception intensity supports this hypothesis. This is the typical modality of a neurochemical blood/brain exchange.
A hypothetical neurotransmitter that convays the 'this is a memory' sensation. A random and sporadic burst of which would inspire the "feeling" of memory while remaining fleeting, ephemeral and puzzling yet scientifically rational.

Memory-based explanations

The similarity between a déjà-vu-eliciting stimulus and an existing, but different, memory trace may lead to the sensation.[3][11] Thus, encountering something which evokes the implicit associations of an experience or sensation that cannot be remembered may lead to déjà vu. In an effort to experimentally reproduce the sensation, Banister and Zangwill (1941)[12][13] used hypnosis to give participants posthypnotic amnesia for material they had already seen. When this was later re-encountered, the restricted activation caused thereafter by the posthypnotic amnesia resulted in three of the 10 participants reporting what the authors termed "paramnesias". Memory-based explanations may lead to the development of a number of non-invasive experimental methods by which a long sought-after analogue of déjà vu can be reliably produced that would allow it to be tested under well-controlled experimental conditions. Cleary[11] suggests that déjà vu may be a form of familiarity-based recognition (recognition that is based on a feeling of familiarity with a situation) and that laboratory methods of probing familiarity-based recognition hold promise for probing déjà vu in laboratory settings. Another possible explanation for the phenomenon of déjà vu is the occurrence of "cryptamnesia", which is where information learned is forgotten but nevertheless stored in the brain, and similar occurrences invoke the contained knowledge, leading to a feeling of familiarity because of the situation, event or emotional/vocal content, known as "déjà vu"...

Related phenomena

Jamais vu

Jamais vu (from French, meaning "never seen") is a term in psychology which is used to describe any familiar situation which is not recognized by the observer.

Often described as the opposite of déjà vu, jamais vu involves a sense of eeriness and the observer's impression of seeing the situation for the first time, despite rationally knowing that he or she has been in the situation before.

Jamais vu is more commonly explained as when a person momentarily does not recognize a word, person, or place that they already know.

Jamais vu is sometimes associated with certain types of aphasia, amnesia, and epilepsy.

Theoretically, as seen below, a jamais vu feeling in a sufferer of a delirious disorder or intoxication could result in a delirious explanation of it, such as in the Capgras delusion, in which the patient takes a person known by him or her for a false double or impostor. If the impostor is himself, the clinical setting would be the same as the one described as depersonalisation, hence jamais vus of oneself or of the very "reality of reality", are termed depersonalisation (or surreality) feelings.

Times Online reports:

Chris Moulin, of the University of Leeds, asked 95 volunteers to write out "door" 30 times in 60 seconds. At the International Conference on Memory in Sydney last week he reported that 68 percent of the volunteers showed symptoms of jamais vu, such as beginning to doubt that "door" was a real word. Dr. Moulin believes that a similar brain fatigue underlies a phenomenon observed in some schizophrenia patients: that a familiar person has been replaced by an impostor. Dr. Moulin suggests they could be suffering from chronic jamais vu.[14]

Presque vu (Tip of the tongue)

Déjà vu is similar to, but distinct from, the phenomenon called tip of the tongue, a situation in which when one cannot recall a familiar word or name, but with effort one eventually recalls the elusive memory. In contrast, déjà vu is a feeling that the present situation has occurred before, but the details are elusive because the situation never happened before.

Presque vu (from French, meaning "almost seen") is the sensation of being on the brink of an epiphany. Often very disorienting and distracting, presque vu rarely leads to an actual breakthrough. Frequently, one experiencing presque vu will say that they have something "on the tip of my tongue".

Presque vu is often cited by people who suffer from epilepsy or other seizure-related brain conditions, such as temporal lobe lability. This is described a glitch of neuropatic nerves in the brain, mainly in the left hemisphere.

In popular culture

Film

Déjà vu provides a plot point in The Matrix, a 1999 science fiction-action film written and directed by Larry and Andy Wachowski. The protagonist, Neo, glances at a cat and comments that he has just experienced déjà vu. Those with a knowledge of 'The Matrix' and its internal workings state that déjà vu means something within the Matrix was altered from its prior state and is referred to as a "glitch".

Television

Déjà Vu was the third episode of the second season of Monty Python's Flying Circus, a British comedy program. Michael Palin plays a television host with the problem.[15]

Music

Déjà Vu has been gaining more notice in current pop culture. Below is a list of artists who have referenced Déjà Vu in their work.

See also

References

  1. Berrios G.E. (1995) Déjà vu and other disorders of memory during the nineteenth century. Comprehensive Psychiatry 36: 123-129
  2. "Neppe Déjà Vu Research and Theory". Pacific Neuropsychiatric Institute. http://www.rebornspirit.com/23.html. Retrieved 2005-11-29. 
  3. 3.0 3.1 3.2 Brown, Alan S. (2004). The Déjà Vu Experience. Psychology Press. ISBN 1841690759. http://books.google.com/?id=5flMtjmezeYC&vq=the+deja+vu+experience+alan+brown. 
  4. "The Meaning of Déjà Vu", Eli Marcovitz, M.D. (1952). Psychoanalytic Quarterly, vol. 21, pages: 481-489
  5. The déjà vu experience, Alan S. Brown, Psychology Press, (2004), ISBN 0-203-48544-0, Introduction, page 1
  6. A Theory on the Deja Vu or Déjà vu Phenomenon
  7. Neurology Channel
  8. Howstuffworks "What is déjà vu?"
  9. PMID 11535020 (PubMed)
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  10. PMID 8149215 (PubMed)
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  11. 11.0 11.1 Cleary, Anne M. (2008). "Recognition memory, familiarity and deja vu experiences". Current Directions in Psychological Science 17 (5): 353–357. doi:10.1111/j.1467-8721.2008.00605.x. 
  12. Banister H, Zangwill OL (1941). "Experimentally induced olfactory paramnesia". British Journal of Psychology 32: 155–175. 
  13. Banister H, Zangwill OL (1941). "Experimentally induced visual paramnesias". British Journal of Psychology 32: 30–51. 
  14. Ahuja, Anjana (2006-07-24). "Doctor, I've got this little lump on my arm . . . Relax, that tells me everything". London: Times Online. http://www.timesonline.co.uk/article/0,,6-2282789,00.html. Retrieved 2010-05-01. 
  15. http://www.ibras.dk/montypython/episode16.htm

Further reading

External links