Deja vu

Déjà vu (/deʒa vy/, in French 'already seen') is a type of paramnesia of the recognition of some experience that feels as if it had been lived previously. Basically it is an event that feels like it has already been lived.

History

This term was coined by the French psychic researcher Émile Boirac (1851-1917) in his book L'Avenir des sciences psychiques (The future of psychic sciences), based on an essay he wrote while studying at the University of Chicago. It is the phenomenon of having the strong feeling that an event or experience that is lived in the present has been experienced in the past. The psychologist Edward B. Titchener, in his book A Textbook of Psychology (1928), explains déjà vu as caused by a person having a brief vision of a object or situation, before the brain has finished "building" a full conscious perception of the experience. Such "partial perception" then translates into a false sense of familiarity. Scientific approaches reject the explanation of déjà vu as «precognition» or «prophecy», but rather explain it as a memory anomaly, which creates a different impression, that an experience is «remembered». ». This explanation is supported by the fact that the sense of "memory" at the moment is strong in most cases, but that the circumstances of the "before" experience (when, where, and how the previous experience occurred) are uncertain. or are considered unknowable.

As time passes, subjects may exhibit a strong memory of having the "disturbing" experience of déjà vu, but little or no recollection of the details of the events or circumstances that have been the subject of the déjà vu itself. This may be the result of an "overlap" between the neurological systems responsible for short-term memory and those responsible for long-term memory, resulting in putative memories of past events being mistakenly perceived as more in the past. far. One theory is that events are stored in memory before the conscious part of the brain has even received the information and processes it. However, this explanation has been criticized on the grounds that the brain would not be able to store information without sensory input first.

Another theory suggests that the brain may process sensory information (perhaps all sensory input) as an "ongoing memory," and that therefore during the event itself one believes it to be a memory from the past. In a survey, Brown had concluded that approximately two-thirds of the population have had experiences of déjà vu. Other studies confirm that déjà vu is a common experience in healthy individuals, with between 31% and 96% of people reporting it. On the other hand, déjà vu experiences that are unusually prolonged or frequent, or in association with other symptoms such as hallucinations, are an indicator of neurological or psychiatric disease.

General information

The experience of déjà vu is often accompanied by a compelling sense of familiarity and also by a feeling of "awe", "strangeness", or "strangeness". The "previous" experience is often attributed to a dream, although in some cases there is a strong sense that the experience "actually occurred" in the past.

The experience of déjà vu seems to be very common. In formal studies, 60% or more of the population claims to have experienced it at least once. References to the experience of déjà vu are also found in literature from the past, indicating that it is not a new phenomenon. It has been extremely difficult to invoke the experience of déjà vu in the laboratory, so few scientific studies have been carried out. Researchers have recently found ways to recreate this sensation using hypnosis.

Types of déjà vu

According to Lucas Barros, there are three main types of déjà vu:

Déjà vécu

Usually translated as 'already lived' or 'already experienced', déjà vécu is described in a quote from Dickens:

We all have some experience of the sensation, which occasionally comes to us, that what we are saying or doing we have already said and done before, in a remote time; of having been surrounded, long ago, by the same faces, objects and circumstances; that we know perfectly what we will say next, as if we suddenly remember it!

When most people talk about déjà vu what they really experience is déjà vécu. Surveys have revealed that up to 70% of the population have had these experiences, typically between the ages of 15 and 25, when the mind is still subject to noticing the change in the environment. The experience is usually related to a very banal, but it is so shocking that it is remembered for years.

déjà vécu refers to an experience that includes more than just sight, so labeling it déjà vu is often inaccurate. The sensation includes a great amount of detail, perceiving that everything is exactly as it was before.

More recently, the term déjà vécu has been used to describe very intense and persistent feelings of a type of déjà vu, which occur as part of a memory disorder.

Let me feel

This phenomenon alludes to something 'already felt'. Unlike the precognition implicit in déjà vécu, déjà senti is primarily or even exclusively a mental event, lacks precognitive aspects, and rarely it remains in the memory of the person who experiences it.

Dr. John Hughlings recorded the words of one of his patients suffering from psychomotor or temporal lobe epilepsy in an 1889 essay:

What occupies the attention is what has occupied it before, and in fact has been familiar, but has been forgotten for a while and now recovers with a slight sense of satisfaction as if it had been looking for.... At the same time, or... more exactly in an immediate sequence, I notice subtly that memory is fictitious and my abnormal state. Remembrance always begins with the voice of another person or my own verbalized thought or what I am reading or verbalizing mentally, and I believe that during the abnormal state I tend to verbalize some phrase of simple recognition as "Ah, yes: I see" or "Of course I remember", but one minute or two later I cannot remember neither the words nor the verbalized thought that gave rise to the memory. I just find the strong feeling that they look like what I've felt earlier under similar abnormal conditions.

Like Dr. John Hughlings' patient, some temporal lobe epileptics can experience this phenomenon.

Let me visit

The déjà visité, which translates as 'already visited', is a less frequent experience that involves the rare knowledge of a new place. Here one can know how to find the way through a new city or place knowing at the same time that it cannot be.

Dreams, reincarnation, and even out-of-body travel have been invoked as explanations for this phenomenon. Also, some suggest that reading a detailed description of a place can lead to this feeling when you visit it later. Two famous examples of such situations are described by Nathaniel Hawthorne in his book Our Old Home and Sir Walter Scott in Guy Mannering. Hawthorne recognized the ruins of a castle in England and later he was able to trace the origin of the sensation to a work written about the castle by Alexander Pope two hundred years before.

C. G. Jung published an account of a déjà visité in his 1952 essay On Synchronicity.

In order to distinguish déjà visité from déjà vécu it is important to identify the source of the sensation. The déjà vécu is related to temporal occurrences and processes, while the déjà visité has more to do with geography and spatial relationships.

Scientific research

In recent years déjà vu has been the subject of serious psychological and neurophysiological research. Its most plausible explanation is that déjà vu is not an act of "precognition" or "prophecy" but rather an anomaly of memory: the impression that an experience is "being remembered." This explanation is corroborated by the fact that in most cases the feeling of "memory" at the moment is strong, but the circumstances of the "previous" experience (when, where, and how it occurred) are quite uncertain. Also, as time passes, subjects may exhibit a strong memory of having undergone the "upsetting" experience of déjà vu itself, but no recollection of the specific events or circumstances that were " reminiscing" when they had that experience. In particular, it may be the result of an overlap between the neurological systems responsible for short-term memory (events perceived as belonging to the present) and those responsible for long-term memory (events perceived as belonging to the past).. Many theorists believe that the memory abnormality occurs when the conscious mind has a slight delay in receiving perceptual input. In other words, the unconscious mind perceives the environment before the conscious mind. This causes the consciousness itself to perceive something that is already in memory, despite the fact that it is only an instant apart from the perception.

Relationships with disorders

A clinical correlation has been found between the experience of déjà vu and disorders such as schizophrenia and anxiety, and the probability of suffering from it is considerably increased in subjects who are in such conditions. However, the strongest pathological association of déjà vu is with temporal lobe epilepsy. This correlation has led some researchers to speculate that the experience of déjà vu it is possibly a neurological abnormality related to undue electrical discharges to the brain. Just as most people experience a mild (i.e., non-pathological) epileptic episode on a regular basis—for example, the sudden "jolt" that often occurs just before falling asleep, or hypnagogic jerk—it has been conjectured that a (mild)) similar neurological aberration occurs in the experience of déjà vu, resulting in a sense of erroneous memory.

Pharmacology

Certain drugs have been reported to increase the chances of experiencing déjà vu. Some drugs, when combined, also cause déjà vu. Taiminen and Jääskeläinen (2001) reported the case of an otherwise healthy man who began to experience recurrent intense feelings of déjà vu when he took amantadine and phenylpropanolamine to relieve flu symptoms. He found the experience so interesting that he completed the treatment and reported it to the psychologists, who picked it up. Due to the dopaminergic action of drugs and previous findings of brain electrode stimulation (for example, Bancaud, Brunet-Bourgin, Chauvel, & Halgren, 1994) Taiminen and Jääskeläinen speculate that déjà vu occurs as a result of hyperdopaminergic action in the medial and temporal areas of the brain.

Explanations based on memory

Neural Theories

In the late 19th and early 20th centuries, it was widely believed that déjà vu could be caused by temporary lapses in neuronal synapses. This lapse was thought to lead the brain to believe that it was experiencing a stimulus a second time, when in fact, it was simply re-experiencing the same event from a slightly delayed source. There are a number of variations on this theory, with miscommunication of the two hemispheres of the brain and abnormally fast neuronal synapses as explanations for the sensation. Perhaps the most widely accepted neural theory is the optical path delay theory, which explains déjà vu as the product of delayed optical input from one eye.

Non-scientific research

Parapsychology

Déjà vu is associated with precognition, clairvoyance, or extrasensory perceptions, and is frequently cited as evidence of "psychic" aptitudes in the general population. Non-scientific explanations attribute the experience to prophecy, visions (such as those received in dreams), or memories of a previous life.

Dreams

Some maintain that déjà vu is the memory of dreams. Although most dreams are never remembered, a sleeping person can present a great display of activity in brain areas related to the long-term memory process. It has been speculated that dreams are "read" directly from long-term memory, bypassing short-term memory.

In this case, déjà vu could be a memory of forgotten dreams with elements common to the experience lived in the waking state. The déjà vu occurs in dreams many times because the brain is reporting something that it thinks, but it does not consciously think and simply warns. The déjà vu are also generated by ideas that come from instinct, when this situation arises, since situations occur again in life many times, you are prepared because they are stored in the memory, although have never happened and are just an unconscious ideation.

Related phenomena

I never saw you

Jamais vu ('never seen', 'never seen'): is not explicitly remembering having seen something before. The person knows that it has happened before, but the experience seems strange to him.

Presque vu

Presque vu ('almost seen'): it is almost remembering something, but without actually doing it. This is the feeling of having it "on the tip of your tongue."

It is commonly mentioned by people who suffer from epilepsy or other diseases related to brain attacks.

L'esprit de l'escalier

L'esprit de l'escalier is a French expression that describes the feeling one gets when the action that should have been taken comes to mind, too late.

Des vu

The awareness that what is being lived in the moment will become a memory.