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It's Deja Vu All Over Again...

gflaherty's picture

            We have all had those moments where we find ourselves in a situation that we consciously know we have never been in; yet, there is a strange familiarity that creeps into the back of our heads. The phenomenon known as déjà vu was first used by French philosopher and psychic, Emilie Boirac, in his book, L'Avenir des Sciences Psychiques (3).  A French phrase for “already seen”, many who experience déjà vu have the feeling that they have actually experienced the same event or situation at a previous date.  This sense of familiarity can be eerily unsettling. 

            Many forms of déjà vu exist. Arthur Funkhouser, a Swiss scholar, was the first to introduce the idea of different levels of déjà vu (2).  The French term déjà vecu means “already lived”.  This term is used to describe the feeling of having experienced an entire situation at a previous time.  From the location to the conversation and the clothing -everything is familiar (1).  Déjà visite means “already visited” and this applies to people who have an overwhelming sense of familiarity with a place that they have never been to before.

            Explanations of this phenomenon have been around for the last one hundred years.  Many have studied this phenomenon because so many people have experienced déjà vu at one time or another.  The explanations of this feeling are numerous and cover a range of areas of science as well as spirituality.  Two main categories that tackle the many explanations in a wide capacity are Associative déjà vu and Biological déjà vu (3).  Associative déjà vuis most commonly believed to be the type of déjà vu experienced by medically‘normal’ people that experience a ‘glitch’ in their memory.  Biological déjà vu incorporates the theory of temporal lobe epilepsy, yet many think that this might be different from déjà vu altogether because it is not a passing feeling but rather alasting belief that the uncanny familiarity with an experience is genuine. 

            Because of the fleeting nature of déjà vu and its elusive behavior, it is hard to identify the true character of déjà vu. It is also difficult to explain the feeling from a scientific standpoint.  One explanation that has been presented is the possibility of a miscommunication between the short-term memory and the long-term memory where short-term memories are perceived as being long-term memories (1). Some have suggested that a specific type of epilepsy within the temporal lobe is responsible for the déjà vu phenomenon.  However, this seems unlikely because such a serious medical condition would hardly account for the large amount of people that experience déjà vu (2).

            There are also many theories with less scientific rooting that are popular in terms of trying to solve the mystery of déjà vu.  Dreams are one way that some people claim that déjà vu can be experienced by so many.  Events that take place in our dreams can be so close to real life that the brain might actually store them as memories, which we draw upon when we are in similar situations, hence the feeling of déjà vu. Although this might be a possibility, there is no evidence to support this theory.  Others claim thatsuch ideas as reincarnation and the possibility of parallel universes are conceivable explanations for déjà vu.

            These explanations are varied and inconsistent because of one extremely important reason:  déjà vu is an unpredictable and fleeting feeling – how does one emulate it in a laboratory? 

            Usingthe fact that people subconsciously see images before they consciously can acknowledge it, Drs. Larry Jacoby and Kevin Whitehouse, psychologists at Washington University, were able to set up an experiment that utilized this information in order to try to create déjà vu.  The experiment

“…had 30 students memorize a list of words as if in preparation for a test. Shortly afterward, the students were asked to sit in front of a computer screen and watch as another series of words appeared, one at a time, and to flag the ones they had seen the first time around. All it took for the researchers to make an unfamiliar word look suddenly familiar was to flash it subliminally on the screen for a few milliseconds. The students' brains registered the word subconsciously, and they were highly likely to say it had been on the first list…” (5).

Many experiments have been conducted in the same manner in order to demonstrate the fact that people register more information than they are aware of on a conscious level.  An explanation of this simplicity might account for the many times that people eerily seem familiar with a place or a situation with which they consciously know they have never witnessed.

            Dr. Alan Brown, a psychologist at Southern Methodist University in Dallas, has done many experiments similar to the experiments conducted by Drs. Jacoby and Whitehouse. Brown has developed what he calls the Cell Phone Theory (3).  This theory states that when the ‘subliminal’ information that the brain picks up subconsciously when one is putinto a new situation is transmitted to the conscious that déjà vu occurs.   This is a new spin on the theory that the brain confuses short-term and long-term memory.

            What I find most fascinating about this topic is that this is a phenomenon that has been felt by such a large majority of people yet it has gone almost completely unquestioned in the realm of scientific experiment.  As many as 97 percent of people have experience déjà vu at one time or another (4).  For sucha well-known phenomenon to be unexplained for such a long period of time is astounding and demonstrates just how much is unknown about the brain.  As a biology major, I find myself looking more to the scientific process involved with trying to achieve some sort of explanation for déjà vu. As Dr. Brown acknowledges, "The most likely thing we'll find is that déjà vu occurs for a variety of reasons, perhaps different in each person, or in different situations…we are just getting started, to work toward an understanding gradually” (5).  For this reason, I feel that studying such occurrences as déjà vu inspire scientists to create innovative and state-of-the-art experiments that will test the boundaries of accepted science, and in turn expand the boundaries of our knowledge of the brain.






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Paul Grobstein's picture

a sense of familiarity?

Its worth noting as a generality that what is most often studied by scientists isn't what is common but rather what one can think of a way to study. Maybe that's the issue here? Yes, of course, people "register more information than they are aware of on an unconscious level". Its not clear to me though that that is the same thing as déjà vu. There is an internal experience associated with the latter, a sense of familiarity, that isn't always associated with unconscious acquisition of information. Maybe the key question is why is it sometimes there and sometimes not?