Déjà Vu: the strange sensation of living something already lived before

Do you know what Déjà Vu is? We explain the psychological keys to this strange phenomenon.

Have you ever experienced something that you think you have already experienced at another time? Have you ever been in a place that seems familiar to you but you don't remember why it is familiar to you?

If you have felt something similar, it is very likely that you have experienced a Déjà Vu.

What does Déjà Vu mean?

Déjà Vu is a French term coined by psychic researcher Émile Boirac that means "already seen" and implies a sensation of experiencing a situation identical to a previously experienced one of which, however, we are unable to remember when or why, we are not able to remember when or why it is familiar to us.. It usually lasts a few seconds and is characterized by the sensation of living again a moment already experienced, as if the same story were repeating itself.

Through a compilation of data by Millon and his team it has been observed that, approximately, 60% of people experience it and that it turns out to be a more frequent phenomenon under situations of stress and fatigue (Brown, 2003). (Brown, 2003). It usually occurs between the ages of 8-9 years, since a certain level of brain development is required for Dèjá Vu to occur, but once we experience it, it becomes more frequent between the ages of 10-20 years (Ratliff, 2006).

When we talk about Dèjá Vu, we are not talking about a new term, since Dèjá vu experiences have already been described in works of great writers such as Dickens, Tolstoy, Proust and Hardy (Sno, Linszen & Jonghe, 1992).

Why does Déjà Vu occur?

This question is still unclear to us. Numerous fields offer various explanations for this phenomenon, some of the best-known theories are those that relate Déjà Vu as a a symptom of paranormal experiences (past lives, premonitions, etc.). and even, in the field of psychoanalysis, Freud (1936) postulated that this sensation was caused by the similarity of the present situation with a repressed fantasy of an unconscious dream, however, he declared the phenomenon as something confusing to investigate.

What does neuroscience tell us about the Déjà Vu phenomenon?

Focusing on a neurocognitive analysis, Alan Brown (2004), psychologist at Southern Methodist University and author of "The Déjà vu Experience", shows us a classification of the various scientific explanations regarding Déjà Vu through four theories:

1. Double processing

The central idea is the affirmation of Déjà Vu as a result of two parallel result of two parallel, synchronized cognitive processes that momentarily lose synchronization..

This asynchrony may be due to the absence of one process when the other is activated or that the brain is encoding the information and retrieving it at the same time, i.e. two related pathways that are normally separated are merging. The fact that we are observing an image and at the same time remembering it gives us a sensation of having previously experienced that situation.

2. Neurological

Déjà Vu is produced due to a brief dysfunction/interruption brief dysfunction/interruption in a circuit of the temporal lobe, involved in the experience of remembering situations.This fact generates a "false memory" of the situation. This theory is justified by the study of patients with temporal lobe epilepsy, who frequently experience Déjà Vu just before suffering one of their seizures.

By measuring neuronal discharges in the brains of these patients, scientists have been able to identify the regions of the brain where Déjà Vu signals begin and how stimulating those same regions can produce the sensation.

3. Mnesic

Defines Déjà Vu as an experience experience generated by the similarities and overlaps between past and present experiences.. Psychologist Anne M. Cleary (2008), researcher of the neural bases underlying Déjà Vu, postulates this phenomenon as a normal metacognitive mechanism that occurs when a past experience bears a resemblance to the present one and, consequently, makes us believe that we have already been there.

Through various studies and research it has been shown that the mind stores fragments of information, that is, it does not store the complete information and, therefore, when we observe, for example, a street that resembles another or that has identical or similar elements, this sensation may arise.

4. Double or attentional perception

It is postulated that this phenomenon is produced as a consequence of a momentary distraction of the brain momentary distraction of the brain just after part of the scene has been captured (non-explicit memory) and, when this attention is retaken (fractions of a second) and performs a complete capture, we attribute to that scene a strong sense of attention.When this attention is retaken (fractions of a second) and performs a complete capture, we attribute to that scene a strong sense of familiarity without being aware of its origin, giving a sensation of "false memory", since part of that scene had been implicitly and unconsciously registered.

The fact that there are several theories shows that such a phenomenon is not due to a single cause. It is also true that not all Déjà Vu is the consequence of a normal mnesic process, since there seems to be a type of Déjà Vu related to a mnesic alteration observed in pathologies such as schizophrenia or, as mentioned above, in temporal lobe epilepsy in which the phenomenon can last for a few minutes or even hours (Thompson, Moulin, Conway & Jones, 2004).

At the moment, there is no clear and definitive explanation as to the anatomical and functional basis for this phenomenon to occur, but advances in the techniques used in the field of epilepsy have been made in the past few years.but advances in neuroimaging techniques and current research may help to better understand the issue from a neurocognitive perspective.

Bibliographical references:

• Brown, A. (2003). A review of the déjà vu experience. Psychological bulletin, 129(3), 394.

• Brown, A. (2004). The Dèjá vu experience. England: Psychology Press.

• Cleary, A. M. (2008). Recognition memory, familiarity, and déjà vu experiences. Current Directions in Psychological Science, 17(5), 353-357.

• Freud, S. (1964). A disturbance of memory on the Acropolis. In The Standard Edition of the Complete Psychological Works of Sigmund Freud, Volume XXII (1932-1936): New Introductory Lectures on Psycho-Analysis and Other Works (pp. 237-248).

• Ratliff, E. (2006). Déjà vu, again and again. New York Times Magazine, 2, 38-43.

• Sno, H., Linszen, D., & Jonghe, F. (1992). Art imitates life: Deja vu experiences in prose and poetry. The British Journal of Psychiatry, 160(4), 511-518.

• Thompson, R., Moulin, J., Conway, M. & Jones, R. (2004). Persistent Déjà vu: A disorder of memory. International journal of geriatric psychiatry, 19(9), 906-907.