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Already Seen, Already Lived: What is Déjà Vu?

Hannah Mueller's picture

"It's déjà vu all over again." Upon hearing this cliché, most people know that it refers to a repetitive, unoriginal situation. They might also be familiar with the meaning of the French phrase "déjà vu": "already seen." Yet only about two thirds of the American population has ever had a déjà vu experience (1), and no scientist in history has been able to definitively explain the phenomenon. What is this sudden, often eerie sensation of having already seen or lived through the present moment, and how does it happen? Recent research on déjà vu, which only a few decades ago was considered unworthy of scientific exploration, has more clearly defined how déjà vu occurs and what is meant by the phrase. "Déjà vu" may actually be a catch-all term for three or four different memory malfunctions, at least one of which can become chronic in people with brain damage.

Defining déjà vu has proved nearly as difficult as describing a déjà vu experience. In 1983, the psychiatrist Vernon Neppe explained the illusion as "any subjectively inappropriate impression of familiarity of a present experience with an undefined past" (3). The words "inappropriate" and "undefined" troubled later researchers in their search for a single cause, because sometimes a "déjà vu" experience actually can be traced back to an experience in the past. Other scientists have found that, in a déjà vu situation, there is a difference between a feeling of "familiarity" and one of "recollection" (4). These discrepancies have caused different categories of phenomena to be created, of which déjà vu is only one.

Arthur Funkhouser, Ph. D., lists three different déjà vu sensations: déjà vécu, déjà senti, and déjà visité (1). According to his research, déjà vécu is what most people experience when they say they have déjà vu. Literally, it means "already lived," which is more accurate because the sensation usually involves all aspects of a scene. Most people undergo an overall feeling of having lived through the moment previously, not only observed it. Another category of déjà vu is déjà senti, or "already felt." Funkhouser describes this feeling as one that does not involve visual stimuli, but is generally triggered by voices. It is a momentary feeling of understanding, which vanishes as quickly as it arises and cannot be specifically recalled afterwards. The third, and most rare, type of déjà vu under this system is déjà visité, or "already visited." This occurs when someone arrives at a location where he or she has never been before, but feels as if he or she knew the layout perfectly. Nineteenth-century author Nathanial Hawthorne described such an experience upon arriving at an abandoned castle in England; much later, he realized his own recognition had stemmed from a description he had read by Alexander Pope (1).

Another study, one by Chris Moulin and Martin Conway, separated déjà vu into two main groups: déjà vécu and, simply, déjà vu. Here, déjà vu refers to a false sense of familiarity, déjà vécu to a false sense of recollection (4). With déjà vu, some familiar object or situation sparks a familiarity sensation, but the person is unaware of what sparked it. An untraceable sense of having been somewhere or seen something before results. This explanation accounts for why most people report being in very ordinary places when they experience déjà vu. Déjà vécu, on the other hand, creates a stronger impression because the person has a "sense of self in the past" (4). He or she feels as if they are actually living through the past a second time. This is a feeling of recollection without a feeling of having any memory to base it on. The difference lies in the fact that during déjà vu, the person feels that if only he or she could recall the correct memory, he or she would know why the situation seemed familiar. Funkhouser does not recognize this distinction between familiarity and recollection, but focuses instead on how we sensually perceive the déjà experience. He would probably group Martin and Conway's déjà vu with déjà vécu, and they would probably group his déjà visité and déjà senti with déjà vu.

Now that we have a better idea of what we mean by déjà vu, what causes it? Psychology professor Alan Brown devised four possible different kinds of causes (2). He recognized that more than one might be true, as there can be more than one cause for a stomachache (3), and does not distinguish which may cause which type of déjà vu. These theories, he hopes, will serve as hypotheses for later experiments. The first explanation, called dual processing, is based on the theory that there are two systems for memory recognition in the brain (2). One is for familiarity, the other for retrieval of information. When the familiarity system is working but the retrieval system is not, or is a split-second slower, we may experience some kind of déjà vu.

The second theory is the neurological theory, which suggests that déjà vu is caused by small misfirings of nerves in the parahippocampal cortex, an area that helps with recognition (2). These sudden spastic nerve activations are akin to mini-seizures; the fact that epileptics often report having déjà vu before going into full-blown seizures supports the neurological theory. Brown's third hypothesis proposes that some aspect of a real memory or dream triggers déjà vu, but the person is unable to place that memory (2). Hawthorne's experience with déjà visité supports this theory. The last theory is called "double perception." Here, a person is interrupted while glancing at something new; when he or she returns to the new thing, it seems strangely familiar. This might happen if someone were driving through a town for the first time on a cell phone, not paying attention to the surroundings. On the way back, because the person is now able to focus, he or she may experience déjà vu because of the "inattentional blindness" experienced the first time (2).

For most people who have déjà vu, the experience is only momentary and occurs infrequently. However, rare cases have been reported in which a patient experiences déjà vu many times a day, or even constantly. Moulin and Conway termed this condition "persistent déjà vécu" (4), because sufferers have a false sense of recollection and believe that their memories are real. Because they are convinced that they are actually "remembering the present," these people are called anosagnostic (3). One of the patients in Moulin and Conway's study was referred to a memory specialist when he complained of his problem; he insisted that he had already been, although he had not. Other sufferers refuse to read books or watch television and sports because they believe they already know every outcome (4).

How can déjà vécu become a real conviction of having "already lived" for those who undergo it all the time? The answer lies in the fact that episodic memory is "content addressable" (4), meaning that a cue will cause it to rise up. A cue could be an object, a scent, or a sound connected with a memory. When we sense the cues, some memories become more accessible than others, but the memories might not be useful to the brain. People could constantly live in a state of recollection if we were unable to stem the tide of these cues, choosing which ones to use. Moulin and Conway theorize that persistent déjà vécu sufferers do have this problem, so they feel as if they are always remembering. In order to rationalize this feeling, they perform "recollective confabulation" (4). This means that when they are asked to explain why they think something is familiar, they fabricate reasons to fill in the gap between what they "remember" and what they are living through "again." For example, one of the test subjects told his wife that he remembered seeing a coin lying in a certain spot on the street because he had put it there for her to find (4). When these patients are told the truth, that the sensation of memory is separate from any real memory (3), they are most often relieved. While the déjà vécu does not disappear, they are more able to continue with their lives in spite of it.

During only the past week or so as I researched and wrote this report, I have heard four or five friends, on different occasions, mention that they had "just had déjà vu." Since, for unclear reasons, one is more likely to have déjà vu if one is a political liberal (2), is between about 15 and 30 (3), is fatigued (3), and has a higher educational background (4), this makes sense. In any case, déjà vu is not an uncommon occurrence, and people consider it worth mentioning when it happens. Yet, in the end, there is still very little definite information about this phenomenon, which affects us so often and so deeply. Sensing that sometimes one cannot trust one's own mind is an unsettling experience, certainly for those who live with persistent déjà vécu, but also for those of us who déjà vu surprises. Knowing how déjà vu happens helps to satisfy our conscious minds when it happens. Sometimes, though, in our unconscious, no amount of rational explanation will dispel that eerie feeling.

Works Cited

1. Funkhouser, Arthur. "Three Types of Déjà Vu." Scientific and Medical Network Review 1995. <>

2. Glenn, David. "The Tease of Memory." The Chronicle of Higher Education July 2004: Volume 60, Issue 46, pg. A12. < free/v50/i46/46a01201.htm> [Or search on Google: "David Glenn Chronicle Deja Vu" and click on first result.]

3. Ratliff, Evan. "Déjà Vu, Again and Again." The New York Times July 2006.

4. Moulin, Christopher J.A., and Conway, Martin A., et. al. "Disordered memory awareness: Recollective confabulation in two cases of persistent déjà vecu. " Neuropsychologia Volume 43, Issue 9, pgs. 1362-1378. [Science Direct]. <>


Anonymous's picture

have any of you thought you

have any of you thought you might be having premonitions and not suffering deja vu? i believe everyone has the ability to 'know who is phoning' at some point, just in some people these things can become more apparent and regular.
surely if it was merely deja vu you would feel a familiar feeling not 'knowing' what was about to happen? a premonition.

Anonymous yest familiar's picture

I had this experience a few

I had this experience a few times before, as well as some other wierd unexplainables....but today the deja vu that I had was different, stronger feelings involved, almost complelling towards something, but I can't wrap by head around it. I think there is more to deja vu and our different levels of perception than we now know. Today I was compelled to write what I felt and so I give this to you my raw emotions....."Significants In Throughout", As I was watching a show that I found realy intereasting, I came upon a scene, and I alrady knew how it would play out before it was done....I finished the scene and paused to reflect on what just happened. The hair on my body stood on edge as I had just realized deja vu had just happened to me. I haven't had this happen many times in my life but none have ever been so strong a feeling as this one. The feeling was indescribable, like two sepperate memories colliding to form one single memory, where every detail I had already known before. The smells, the position of everything in my living room. How I was positioned, what I was looking at, at that exact moment. It was such a lucide experience of deja vu, it actaully sent the hairs on my body on their edge and I got a tingly sensations all over, the eerie feeling would not subside so I wrote about it. It helped some but it is still there in the back of my memory far from my main though, but not to far....There are other things I have had happen in life, like dreaming of a car accident, and then experiencing it for real at a later about strange....anyways just wanted to share my experience.

Think about this for a second, if reality is all just based on processes of the breain that formulates our perception of reality, then how do you realy know that what you are seeing is real, or just your brain showing you what you want to see....if the mind is so powerful.

hanna's picture

deja vu

I have had deja vu many times that I can not recall. The most recent one happened about a week ago. I was haning onto a monkey bar at my school talking to my friend, I felt in the same angle and are and place. I felt exactly the same feeling I had before but really I was never in this position before. It could be from a past life. The weird thing is sometimes your conscience have been in a past life but then you think that is bizarre. You really can not explain what can ca8use deja vu., but I belive you have lived before.

spacenomad's picture

I'm 21 and I've been having

I'm 21 and I've been having intense deja vu's many times every day. Doesn't it mostly happen to old people?

To much, u 13 year old!.. your experience is interesting. since how long have you been having a lot of deja vu's?

Anonymous's picture

To Much

I'm only 13 years old, and yet I experience Deja Vu almost every day. Just yesterday I had three of them in less then five minuets! It could happen in a simple movement or If I'm about to say something to a friend; all of a sudden this really strange feeling comes over me and I feel like have already done something right before I do it or as I'm doing whatever it is I'm having Deja Vu for.

Brianne's picture


I'm 17, and i have had many experiences of the past week i have had around 4 episodes of this. This really weird feeling comes over me, and i always say "i've already done this" in school, i've done a certain assignment before when really its a new one, or i've heard news about a certain subject before when it is brand-new tonight, i watched the local news with my mom and a story that just happened recently, i have already seen and heard about, strangest feeling came over me, i knew exactly what the reporter was going to say...


Anonymous's picture


Thank you for your information, I googled it and your blog popped up. I have a presentation on deja vu and its so hard to explain. But your explanations helped out a lot! Thanks again!

Strange's picture


I had this experience many times and i am a kid im only 13 years old....

Serendip Visitor's picture

: )

It's weird to comment hehe...but I really like this paper! It's very interesting. And I'm gonna make the joke: I feel like I read it before...Oh, man...Anyway, great job! : ) Much love, Alison