Deja Vu: Haven't we been here before?
Déjà vu: the inexplicable sensation that one has seen or experienced a particular episode before. The term itself, when translated literally from its French origin, becomes: “already seen.” Yet, true déjà vu seems to trigger additional physiological reaction which accompanies the simple sense of vision. What could trigger such a reaction within the human mind? Several explanations for the phenomenon known as déjà vu have been proposed, each of which could account for its unusual sensation.
A theory has been proposed for ages that déjà vu is the occurrence of a prescient glimpse into the future. Mass paranormal belief that certain individuals possess the gift of prophecy or fortune telling has waned only slightly over the last several hundred years. Within such a climate, the prospect to an ordinary individual that he or she could have their own individualized psychic experience, might create enough exhilaration to overcome any preconceived notions or skepticism that would have precluded such a conclusion previously.
A considerable proportion of these supposed premonitions occur while the recipient is asleep. Many subjects report that the event or place that they have not yet experienced, but encounter subsequently, first appeared to them as a dream. As opposed to the figurative and metaphorical imagery that dream interpreters attempt to decipher, these literal visions are a precursor to the tangible experience that is to occur later on in the subject’s life.
Ostensibly, with as much as 70% of the world’s population reporting having experienced déjà vu, anecdotal evidence would suggest that psychic and precognitive ability are far more prevalent than originally thought. Additionally, research indicates that incidents of déjà vu occur in higher percentages in the 15 – 25 year-old age range. How would the prophetic theory of déjà vu account for this specifically targeted age demographic? While this school of thought probably seems fanciful to the majority of the population; it does account for the sensation of having experienced a place or event that one could not have possibly witnessed before.
Another theory from the realm of the paranormal identifies an external force as the cause of the déjà vu experience…reception of messages from outer space. Apparently, any individual who experiences déjà vu has latent telepathic abilities. These abilities allow them to receive messages which originated from elsewhere in the universe. These communications could have been generated through mechanical means, or from another telepath. In essence, the extra-terrestrial message is received-yet indecipherable- to the human mind. Therefore, the brain interprets the data received in visions or terms that it can relate to. This line of reasoning posits that the internal conflict generated by the human mind as it struggles to comprehend the other-worldly information affects the entire person; thus making déjà vu a near visceral experience.
The final paranormal explanation for déjà vu originates in one of the most prominent, and recognizable, tenets of the Hindu religion: reincarnation. If one accepts the premise on which it is based, reincarnation is the most plausible of the paranormal explanations on the subject. Ostensibly, the person experiencing déjà vu is merely remembering the location or event from a past life. The individual has “been there” and “done that,” just not during his or her present existence. As with the alien telepathy explanation previously mentioned, this memory from a prior existence theory is able to account for the overall palpability of the déjà vu experience. While one of these paranormal causes to déjà vu accounts for the unsettling feeling that it can bestow upon a recipient; science in general and the study of human medicine in particular, proposes a different genesis for the experience.
In his instructive manual, A Textbook on Psychology, psychologist Edward TItchener suggests that déjà vu occurs when a person’s mind constructs a “partial perception” based on an insufficient glimpse of an object or situation. Because the brain did not have sufficient opportunity to fully construct a complete “conscious” perception of the experience, déjà vu is the resultant sensation due to a false sense of familiarity based on the incomplete perception. It is believed that the section of the human brain called the hippocampus has constructed an entire “road map” charting the experience, when the complete route has not been traveled. As a result, when encountering the stimulus again, the mind follows the designated corresponding road to its end.
Still other research-based hypotheses suggest that déjà vu is an “anomaly” of memory. An overlap between the neurological centers which regulate short-term and long-term memory generates the often uneasy feeling of having experienced the event or visiting the location previously. This explanation gains credence in many cases based on the fact that the sense of “recollection” is considerable while experiencing déjà vu; yet, the details relating to the “previous” event on which the recollection is based, are irretrievable or uncertain at best. Essentially, the overlap has caused the mind to perceive memories forming as spontaneous events occur, as being stored memories from the distant past.
Another postulation suggests that certain sensory memories might be stored away before the conscious mind has even had time to process them. This theory could explain why more than just the sense of sight is capable of triggering déjà vu. Sounds, scents, tactile sensations, and even tastes can also provide impetus for the feeling of recognizable familiarity. However, this particular theory meets resistance from certain factions of the scientific community that cite that the brain would be incapable of categorizing the sensory input for storage if the conscious mind did not have the opportunity of classifying them first.
Antiquated medical explanation for the phenomenon linked déjà vu with schizophrenia and dissociative identity disorder. Subsequent study has dismissed these disorders; but, at the same time, has correlated a pathological disorder known as temporal lobe epilepsy with the presence of the phenomenon. Speculation suggests that déjà vu is an abnormal neurological circumstance in which an unusual electrical discharge occurs within the brain—equating déjà vu to the sudden “jolt” (hypnogogic jerk) that the human body can frequently experience before falling asleep. This theory continues to gain momentum and ever-widening acceptance within the scientific community.
Scientists have also explored the potential for a genetic explanation for déjà vu. While a specific gene associated with déjà vu does not exist, a gene on chromosome 10 is undergoing further study for a possible link.
A pharmacological explanation posits that several drugs can induce déjà vu when interaction with certain other medicine occurs. For example, a number of separately conducted case studies observed several intense and recurring instances of déjà vu among a small percentage of sample groups when the drugs amantadine and phenylpropanolamine were taken concurrently to battle flu-like symptoms. “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), Taiminen and Jääskeläinen speculate that déjà vu occurs as a result of hyperdopaminergic action in the mesial temporal areas of the brain” (Taiminen & Jaaskelainen, 2001).
Concluding the myriad of scientific explanations for the phenomenon, several psychoanalysts have proposed that déjà vu is nothing more than simple fantasy or wish fulfillment. Opponents of this theory observe that this basic explanation might be true if all instances of “recollection” occurred when visiting exciting destinations or encountering pleasurable experiences; yet, the majority of reported cases occur during mundane or unremarkable situations.
Clearly, further study into the phenomenon of déjà vu needs to be conducted to determine a definitive cause behind its occurrence. Some researchers have speculated that differentiations between “deja experiences” might be the key to the mystery. They suggest that the slightest nuance from one instance of déjà vu to the next within the same individual must be meticulously studied; for an emerging pattern could pinpoint the origin of the events.
Déjà vu, like other contemporary unexplained commonalities, has become ingrained in pop culture. Recognition of the phenomenon is present across all age and educational boundaries. Although there is irrefutable acceptance of déjà vu, there is not consensus as to its cause. So while researchers continue to study the possible origin of the phenomenon, this old axiom sums it up most succinctly: (with a tip of the hat to Yogi Berra) “It’s like déjà vu, all over again.”