Article previously published in the magazine, a highly recommended online platform that specializes in neuroscientific courses and publications.
Who has not ever had the disturbing feeling of repeating an experience already lived even though it is actually totally new? This phenomenon, named by Emile Boirac as deja vu (“already seen”, in French) more than a century ago it aroused the curiosity of hundreds of scientists throughout history.
He deja vu or paramnesia is a psychological reaction that causes the brain to tell the person that it has been in the place where they are without perhaps having ever been, or that they know someone, even if they have never seen them before, or even that You feel something that you didn’t feel on another occasion. In short, it is the experience of perceiving yourself as a previous witness of a new situation, but which in reality never occurred.
This sensation lasts between 10 and 30 seconds (hallucinations and false memories with which it is often confused last much longer) and has an unpredictable and fleeting nature that is related to the process of memory and human consciousness.
It occurs because the brain has several types of memory. The memory immediate, capable of repeating a telephone number and then forgetting about them; that of short termwith events that are perceived as belonging to the present and lasts a few hours, and that of long termwith events that are distinguished as belonging to the past and we preserve for months or even years.
If you value articles like this, consider supporting us by becoming a Pro subscriber. Subscribers enjoy access to members-only articles, materials, and webinars.
Feel a Deja vu It is really a technical problem of the brain; as a kind of memory anomaly, where events that are happening are stored directly in long-term or short-term memory, when the correct thing would be for them to go to immediate memory, thus giving the impression that the event has already occurred before .
There are several theories, on the neuroscience side, that try to explain this phenomenon. Among them we find the proposal of Alan Brown, psychologist at Southern Methodist University and author of “The Déjà vu Experience”, where he shows a classification of the various scientific explanations in relation to deja vu:
The central idea is the affirmation of deja vu as a result of two synchronized parallel cognitive processes momentarily losing synchronization. This asynchrony may be due to the absence of one process when the other is activated or to the fact that the brain is encoding information and retrieving it at the same time, that is, two related pathways that are normally separated are merging. The fact of observing an image and at the same time remembering it gives us a feeling of having previously experienced that situation.
He deja vu It is produced due to a brief dysfunction/interruption in a circuit of the temporal cortex, involved in the experience of remembering experienced situations. This fact generates a “false memory” of the situation. This theory is justified by the study of patients with epilepsy of the temporal cortex, who often experience Déjà Vu just before suffering one of their attacks. By measuring neuronal firing in the brains of these patients, scientists have been able to identify the brain regions where the signals begin.deja vu and how by stimulating those same regions it is possible to produce that sensation.
Define deja vu as an experience generated by the similarities and overlaps between past and present experiences. Psychologist Anne M. Cleary (2008), researcher of the neural bases underlying deja vu, postulates this phenomenon as a normal meta-cognitive 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 complete information and that, therefore, when we observe, for example, a street that looks like another or that has identical elements or similar, this sensation may arise.
It is postulated that the phenomenon is produced as a consequence of a momentary distraction of the brain just after part of the scene has been captured (non-explicit memory). When this attention is returned (fractions of a second) and makes 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 it had been registered implicitly and unconsciously.
The fact that there are various theories shows that such a phenomenon is not due to a single cause. Likewise, it is true that not all deja vu is a consequence of a normal memory process, since there seems to be a type of deja vu related to a memory alteration observed in pathologies such as schizophrenia or, as mentioned above, in epilepsy of the temporal cortex in which the phenomenon can last a few minutes or even hours (Thompson, Moulin, Conway & Jones, 2004) .
Through data collection by Millon and his team, it has been observed that approximately 60% of people experience it and it turns out to be a more frequent phenomenon under situations of stress and fatigue (Brown, 2003).
It usually arises between 8-9 years of age, since for a deja vu a certain level of brain development is required. However, once experienced, it becomes more frequent between 10-20 years of age (Ratliff, 2006).
Although most people perceive this alteration of reality on many occasions in their lives, in some cases the anguish caused by the experience of the deja vu itself can lead to higher levels of deja vu, similar to the feedback loops manifested in other anxiety states, such as panic attacks. That is why many scientists assume that, for neurobiological reasons, anxiety can lead to the generation of this phenomenon.
In any case, it is also true that as one ages or as degenerative processes such as Alzheimer’s progress, it becomes more difficult to form unique memories for similar places or experiences and it is very likely to lead to the confusion of déjà vu that afflicts the elderly and those They take care of them. So, the deja vu or paramnesia is, therefore, a memory problem that occurs in the brain and over the years this failure occurs more frequently. That is why it is usually common in people with Alzheimer’s disease.
While that time arrives, suddenly, in the middle of any moment, the feeling arises that the same scene has already been experienced or dreamed of before. What surprises and horrifies many is the aforementioned sensation of deja vu!
By: Mr. Luis M Labath, Former Medical Director of the José M. Cullen Hospital. Period: 2002-2007.