The feeling of perceiving something as familiar, even though you have never experienced that before is known as déjà vu.Most people experience déjà vu at some point in their lives. This phenomenon occurs more in younger people, as opposed to elders.The concept of déjà vu has been around for ages. However, the term was officially recognized towards the end of the 19th century. Considerable research has been carried out in this field. Even psychoanalysts have tried to fully comprehend why people experience déjà vu.A number of reasons have been held as the cause for déjà vu. While some research focuses on the interplay between short and long-term memory, other kinds of scientific research have highlighted the role of mental health, neural processing mismatch, and so on in the occurrence of déjà vu. In addition, focal seizures, which are caused due to issues in the temporal lobe, also cause déjà vu. Further, many people have associated spiritual reasons with these happenings. For instance, déjà vu can be a message from one’s own soul.To learn more about déjà vu, keep reading!What is déjà vu?Déjà vu is the feeling of familiarity that most of us have felt at one point or the other. A déjà vu experience is highlighted by intense feelings of perceiving a situation to be more familiar or known than it really is. The word déjà vu in itself has been taken from French and incorporated into the English language without being translated. Nevertheless, its translation stands for ‘already seen.’ Emile Boirac, a French philosopher, can be credited with the conception of this term.A majority of people, 60-70% to be exact, experience déjà vu. The first experiences of déjà vu usually occur between the age of 6-10. However, the age group that has déjà vu experiences more often are between 15-25. A déjà vu experience can be triggered at any moment. For instance, a person can walk into the room and get a strong sensation that they’ve been in that room before. However, since déjà vu experiences last only for a few seconds, it is not very easy to recollect the strange memory or sensation again.The history of déjà vu can be traced back to ages ago. Quite fascinatingly, the earliest known record of this strange experience can be attributed to Saint Augustine. In 400 A.D. Saint Augustine named this phenomenon ‘falsae memoriae,’ which translates to false memory. Years later, in the 1800s, there were some recorded cases of that eerie feeling of familiarity again. For instance, in the year 1815, Sir Walter Scott published a novel titled, ‘Guy Mannering,’ or ‘The Astrologer,’ which described an incident that included a déjà vu experience. Another famous literary allusion to déjà vu was made by Charles Dickens in his book ‘David Copperfield.’ The book was published in 1815 and continues to be one of the most cited references for déjà vu experiences.Towards the end of the 19th century, the term ‘déjà vu’ was officially proposed to refer to this phenomenon. With F.L. Arnaud’s proposition of this term in 1896, déjà vu not only gained a name for itself but additionally became a topic of interest within the scientific community.The case F.L. Arnaud presented to support his cause was that of a person who had amnesia after suffering from cerebral malaria. Once the man, whose name was Louis, recovered, he felt a sense of familiarity, even for events that did not happen.Causes Of Déjà VuResearchers and common people have attributed a number of underlying causes for déjà vu. Scientists usually conduct observational studies, experimental studies, or both, in order to arrive at a coherent theory about this phenomenon. Let us now look at how far science has gone in the field of déjà vu.One of the basic theories behind the occurrence of déjà vu is that the incident really did happen, and then it may have simply slipped out of the person’s memory. In this case, when something like that happens again, the brain might give the feeling of familiarity without the person understanding why it led to a déjà vu.The next theory is known as the ‘Dual Processing Theory,’ which simply highlights a processing error in the brain cells. To put it simply, when two cognitive pathways are supposed to act in sync together but end up being mismatched, false memories are formed.The ‘Divided Attention Theory’ states that one can experience déjà vu if they perceive a single moment or event simultaneously. Also known as split perception, in this situation, the brain might perceive a situation in an incomplete manner for the first time, followed by a more clear perception of the same situation, leading to the person feeling they already have a memory of whatever they are observing.Another common cause that could lead to intense feelings of déjà vu is delayed neural transmission. There are two variants of this case. In the first situation, only a single neural pathway is delayed, while in the second situation, one of the neural pathways becomes slow in comparison to the other. While the first may give a feeling of familiarity, the second situation leads to someone feeling they’ve predicted the situation that just occurred.A much more serious cause of déjà vu is epilepsy. Those that are suffering from temporal lobe epilepsy tend to experience déjà vu right before they have a seizure attack. This seizure is also known as a focal seizure. This is because the temporal lobe of the brain is responsible for processing emotions and short-term memories. Hence, temporal lobe epilepsy leads to the weird experience of déjà vu, and the focal seizures eventually lead one to lose consciousness.In those who have a seemingly healthy brain and do not suffer from temporal lobe epilepsy, a déjà vu could be a tiny seizure that occurred in the temporal lobe area of the brain. While in most cases, déjà vu is a sign of strong recognition memory, for some people, this might be a warning sign to get their nervous system checked.Symptoms Of Déjà VuThe symptoms of déjà vu encompass some specific sensations. These sensations have most likely been felt by almost everyone.The most common symptom of déjà vu is the feeling of knowing a certain place even though you have never been there or feeling like a situation that is just happening has occurred before. Even though such feelings seem to be quite strong, they only last for a few seconds.In some people, chronic déjà vu has also been observed. In this case, the sensation is the same, but it persists throughout. Researchers have suggested in such people that the temporal lobe has failed permanently, and hence, resulted in the creation of memories that aren’t true.Overall, the most common kind of déjà vu is associative déjà vu. In this type of déjà vu, people smell, hear or see something particular that makes them associate that perception with something they’ve smelt, heard, or seen before.In the case of epilepsy affecting the temporal lobe, which leads to seizures, déjà vu is one of the symptoms. In this sort of déjà vu, which is referred to as biological déjà vu, the sensation of having encountered a scenario previously is stronger than in associative déjà vu, which is the more common type. Other symptoms associated with such a seizure are muscle twitching, sudden emotions like anger or joy, and not being able to control one’s own muscles.Explanations For Déjà VuApart from focal seizures, split perception, and so on, a number of other explanations have been given to make sense of why one can experience déjà vu.A prominent explanation for déjà vu is the occurrence of memory mismatch. In this case, the brain itself is aware of the conflicting memory signals that it is receiving, resulting in déjà vu. While many theories point at the temporal lobe being the cause behind déjà vu, in this case, the hippocampus gives feelings of familiarity.The science of déjà vu also encompasses the concept of dreams. For instance, sometimes déjà vu recreates dream memories instead of real ones. Research has shown that there is a strong connection between dreams and déjà vu. Further, dream frequency is also related to déjà vu.Lack of sleep, in addition to exhaustion, stress, and even traveling, can incite feelings of déjà vu in a person. This is because a stressed-out brain has more chances of misprocessing information or delaying neural pathways. Further, lack of sleep can also lead someone to pay undivided attention, and hence, they experience déjà vu.The presence of a dominant eye can also result in déjà vu. In this situation, the stronger eye perceives its surroundings faster before the other eye can process them. Even though the delay in vision is just for a few nanoseconds, it is enough to create a familiar feeling.Cryptomnesia, when the brain forgets a piece of information, even though it is still stored within the brain, is a probable cause of déjà vu. Cryptomnesia is influenced by how the brain reconstructs memories more than recollecting them.Apart from scientific explanations, a number of spiritual reasons are also used to explain déjà vu. One reason could be that the person’s higher self, or soul, is trying to get in touch with them to let them know that they are on the right track in their life.Many people also think that déjà vu is essentially a recollection of one’s past life. So, within the brain, the past and present lives collide to give a familiar sensation, which is termed déjà vu.Overall, déjà vu is one of the most common experiences felt by almost everyone at some point. However, the exact scientific explanation causing these feelings is not known. The occurrence of déjà vu does not necessarily indicate an unhealthy brain. However, it can be a symptom of seizures and temporal lobe epilepsy.
The feeling of perceiving something as familiar, even though you have never experienced that before is known as déjà vu.
