Probing Question: What causes deja vu?

Feb 12, 2010 By Dawn Stanton

If you've ever had that fleeting, mysterious sense that something new -- a city or person you’re seeing for the first time -- is somehow familiar, that you’ve been there or known them before, then you can count yourself among those who have experienced déjà vu. It’s typically a brief sensation, lasting no more than 10 to 30 seconds, but 96 percent of the population claims to have experienced at least one occurrence.

“Déjà vu, a French term meaning 'already seen,' is considered a disconnect or clash between objective unfamiliarity and a subject sense of familiarity,” said Claire Flaherty-Craig, a consulting and treating at Hershey Medical Center. “It’s been most closely studied in epilepsy, where patients often experience it before a seizure. The brain regions for memory are in the temporal lobes, and there’s an area for monitoring memory accuracy in the middle frontal lobe. Those patients reporting déjà vu are temporal lobe seizure patients. The actual trigger for it in healthy individuals is not exactly known, but we do know those same regions of memory and memory monitoring are involved.”

The concept of déjà vu has been around since French philosopher and researcher Émile Boirac coined the term in 1876. Proponents of psychic phenomenon quickly latched onto it as evidence of past lives, while early psychiatrists and psychologists bandied about various theories to explain its occurrence: Sigmund Freud attributed it to repressed desires. Carl Jung suggested it arose from tapping the collective unconscious. Dozens of “causes” of déjà vu have been proposed over many decades, said Flaherty-Craig, but most fall by the wayside as researchers learn more about the human brain and cognitive processes.

“There was a long-standing theory about a visual disconnect,” she said. “It was thought that one hemisphere of the brain would process the visual information first and so the delayed information reaching the other hemisphere was processed like a memory.” However, recent studies done on the blind have challenged this idea, and Flaherty-Craig noted at least one case where the blind individual reported déjà vu involving hearing, touch and smell.

One popular belief is that déjà vu might result from an accumulation of life experience, but science says otherwise, said Flaherty-Craig. “Statistically it occurs more in late adolescence and frequency of episodes declines with age.”

She offered a déjà vu experience of her own from early adulthood as an example.

“After college graduation, I took five weeks and went on a hiking trip in Ireland. When I was on the west coast hiking one day, I had a very distinct feeling, a real strange sense that I’d been there already. I could even envision what the landscape looked like around the bend in the road, and about an hour later when I reached there, that’s what it looked like. I had discounted the idea of previous lives and things like that by my late teens and was already looking for more scientific explanations for the world, so when I had the experience, it kind of made me a believer that things like déjà vu even existed.”

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baudrunner
1 / 5 (1) Feb 12, 2010
I think that deja vu is a quantum phenomenon. In theory, everything is reallly happening at the same time in the same place. If, for example, we could reduce the temperature of the entire Universe to absolute zero, it would exhibit the characteristics of a single atom.

Flaherty-Craig's experience is not so weird when seen in light of this, insomuch as quantum reality isn't weird, which it is actually. Anyway...
Jamesjsheridan
not rated yet Feb 12, 2010
This phenomenon is related to deja vu:
http://www.news-m...ess.aspx

The difference between artificial life and biological life is also related to the cause of deja-vu.
just_doug
not rated yet Feb 12, 2010
Other research several years ago already demonstrated deja vu could be triggered almost on demand in normal subjects by subtle placement of a familiar object in an unfamiliar setting.

I thought the internet was supposed to facilitate the spread of new knowledge but perhaps the publish or perish pressures cause it to be willfully ignored.
OregonWind
not rated yet Feb 12, 2010
'Text to speech' needs to learn that the term déjà vu is already incorporated into English - dictionary.com

:) cheers
CSharpner
not rated yet Feb 12, 2010
The article seemed to suggest that deja vu was just "familiarity" with something new. Every time I've experienced it, it was an entire event that seemed to be a repeat. For me, it's usually just some mundane, random moment that lasts about 10-30 seconds, just as the article says, but as it's happening, it's like the event has already taken place and I'm witnessing it again (sometimes it feels like it's the unteenth time). In rarer cases, I'm /almost/ sure I "know" what's going to happen next, but I've never really convinced myself of that... It's more of a "feeling". It'd be hard to convince me there's anything supernatural or even pre-cognative going on. I've always assumed it was more like the live event was "being processed as a memory", triggering that type of sensation that it had happened before.
Quantum_Conundrum
1 / 5 (1) Feb 12, 2010
Well, what I experienced is NOT Deja Vu then, because I've actually described events ahead of time to others, or written them in text files, some of which I still have on my computer, and then seen them played out before my eyes, as stated, sometimes word-for-word accurate conversations with 2 or more exchanges of dialogue, or the contents of a UNIQUE document I had never seen before..ahead of time...
GaryB
not rated yet Feb 12, 2010
I get recurring deja vu ... in my dreams. I'm dreaming, getting chased by some enemy when I realise that "I've dreamed this before" and know exactly where to hide to get away. I'm not even sure I did dream these events before, but they are filled with deja vu. I've experienced deja vu in waking life, usually on hikes on trails in the Sierra where the small of pine needles seems to bring it on.
drewgrey
Feb 12, 2010
This comment has been removed by a moderator.
NeptuneAD
not rated yet Feb 13, 2010
Well, what I experienced is NOT Deja Vu then

Depends on what part you are talking about, sounds like precognition first then when the event actually happens you would experience the 'Deja Vu' feeling.
ubavontuba
3 / 5 (2) Feb 13, 2010
I know I already typed a response to this...
DoubleHelix
not rated yet Feb 13, 2010
I personally have witnessed an event that I know for certain I had dreamed in advance, because I remember making commentaries to myself about particular things. It was in a tiny airport terminal in a remote area of Northern California, while at the time I dreamed it I was living in Phoenix, so when I first dreamed it I thought to myself, "Hmmm, this terminal is tiny. I wonder what far corner of the Phoenix Airport this is." Other events also triggered memories of prior commentary about them. I recognized this instantly upon seeing the events in real life, and I know of no scientific explanation for this phenomenon. I have since had senses that I might remember certain events from dreams, but never as definitively as the time I described.
mary_hinge
not rated yet Feb 13, 2010
Reminds me of that film 'Groundhog Day'. I can never remember who starred in it.
artfunk
not rated yet Feb 13, 2010
There is a lot of information available about déjà phenomena at www.deja-experien...arch.org
KB6
5 / 5 (1) Feb 13, 2010
If any of you claiming "supernatural" or "paranormal" ability can prove it in a controlled, experimental setting, you have over ONE MILLION DOLLARS waiting for you!:

http://www.randi....nge.html

I can't wait to see who here claims it first!

Quantum_Conundrum
1 / 5 (3) Feb 13, 2010
If any of you claiming "supernatural" or "paranormal" ability can prove it in a controlled, experimental setting, you have over ONE MILLION DOLLARS waiting for you!:

http://www.randi....nge.html

I can't wait to see who here claims it first!



I've never claimed to have control over it, and I often don't know which dreams are "real" and which are "just dreams" UNTIL after they happen. There have been some exceptions though.

For example, when I dreamed Katrina and Rita ahead of time, I did not "know" it was real, only had a very strong feeling that it probably was real.

After Katrina happened, I KNEW exactly where Rita was going to landfall, weeks ahead of time, only I didn't know "which" storm it was ahead of time, until it crossed over Katrina's path just like it had done in the dream...
Quantum_Conundrum
1 / 5 (4) Feb 13, 2010
I am not a psychic.

I believe in God and believe God speaks to people in dreams and visions, as seen in the Bible many times.
Chef
not rated yet Feb 13, 2010
I have always believed that deja vu is linked to our ability of pattern recognition. When we look at anything (ie., a person's face or location), we search out patterns which in turn links to memories or per-conceptions of experience(meaning if you look at a round object, even if you never seen it before, you still know that will roll along the floor). In the case of deja vu, we experience an "incomplete link" in that certain patterns match for a stored memory or experience, but the remaining patterns fail to make a match. So we get "the feeling" we seen this before, but something if off. This could also work for our other senses as well.
mary_hinge
5 / 5 (3) Feb 13, 2010
Reminds me of that film 'Groundhog Day'. I can never remember who starred in it.
mayan
1 / 5 (1) Feb 14, 2010
deja vu occurs due to many reasons, the body spirit during sleep leaves the body,astral travel, during sleep and sees the issue or the place, the next day or so u get the feeling....this is also clairvoyance/astral travel done by many Gurus.

Astral travel just when you are about to sleep occurs to many, suddenly you will be falling down to earth or end less hollow area, for some people During deep sleep you will be flying without control.

Astral travel is spirit leaving the body with a silver thread connecting body and spirit
diggergig
not rated yet Feb 14, 2010
For those who feel that their dreams are sometimes later confirmed by real experiance, I would recommend the book: 'An Experinment with Time' by J W Dunne.

I believe the type of 'deja vu' referred to in this article is indeed caused by an organic malfunction in our perceptive abilities. A temporal lobe seizure appears the most realistic answer.
mary_hinge
5 / 5 (3) Feb 14, 2010
Reminds me of that film 'Groundhog Day'. I can never remember who starred in it.
diggergig
not rated yet Feb 14, 2010
For those who feel that their dreams are sometimes later confirmed by real experiance, I would recommend the book: 'An Experinment with Time' by J W Dunne.

I believe the type of 'deja vu' referred to in this article is indeed caused by an organic malfunction in our perceptive abilities. A temporal lobe seizure appears the most realistic answer.
goldengod
not rated yet Feb 14, 2010
Some people theorise that deja vu is the future self projecting awareness of an event to the past self. It's a good habit to get into. When you experience an event that is important send a mental note to your past self to make sure you are aware when the event is about to happen or afterwards so that you have a confirmation of sorts that you are on the right track.

If there are 12 dimensions then maybe this is a way of communicating through one of them.
Rawley
not rated yet Feb 14, 2010
Reminds me of that film 'Groundhog Day'. I can never remember who starred in it.


I like what you did there. :)
RobertKLR
not rated yet Feb 14, 2010
I experience Vuja De all the time. Vuja De is the feeling you've never been there before.
Aquatik
not rated yet Feb 14, 2010
i wonder if there is a possiblity that deja vu is really just us experience time in a sense that is unfamiliar. sort of the same way dr. manhattan from the movie Watchmen experienced time. he saw it as a whole instead of minor fragments, for lack of a better explaination.

i know physics states that time can travel forward as well as in reverse. so wouldn't be sound to believe that our brains are evolving to percieve these changes.
briskwalk
not rated yet Feb 15, 2010
Seems like I read this before...
Maybe I just dreamed about it. Deja vu.

briskwalk
www.mercerpublish...gat.html
DeeSmith
not rated yet Feb 20, 2010
Pretty sure the 'sensory disconnect' theory is correct, because a familiar cue occurs in an unfamiliar setting, causing the brain to scramble for an experiential frame of reference, generating a feeling of 'been there, done that'. JustDoug mentions studies that induced this phenomenon. Surely, many of you had this deja-vu feeling, in seeing a face or hearing a voice that was familiar, but the person was unknown to you. In fact, what you are doing is a mismatch of pattern recognition, based on commonly occuring phenotypes in humans (similar, but not identical looking faces, for instances) or, in the case of a place, mismatching a geographical element (a common method of navigating by memory through our environment) that occurs in a place to new to us.

Why would this occur more often in late teen years? This is the period when mirror neurons are reshuffling memory storage networks, translating previous experience to new memory centers.
DeeSmith
not rated yet Feb 20, 2010
Pretty sure the 'sensory disconnect' theory is correct, because a familiar cue occurs in an unfamiliar setting, causing the brain to scramble for an experiential frame of reference, generating a feeling of 'been there, done that'. Surely, many of you had this deja-vu feeling, in seeing a face or hearing a voice that was familiar, but the person was unknown to you. What you are doing is a mismatch of pattern recognition, based on commonly occurring phenotypes in humans (similar, but not identical looking faces, for instances) or, in the case of a place, mismatching a geographical element (a common method of navigating by memory through our environment) that occurs in a place to new to us. Why would this occur more often in late teen years? This is the period when mirror neurons are reshuffling memory storage networks, translating previous experience to new memory centers.
infinitePi
not rated yet Feb 21, 2010
there is something like deja-vu that i have experienced.. in one of my engineering classes in college one of my project partners was talking about hockey(i have never watched hockey in my life), and halfway through one of his sentences i had this feeling that i had heard it before. but unlike previous deja-vu i have experienced, i remembered exactly what he was going to say next. so i decided to say to him what i remember him saying..therefore changing the situation in my dream, and i felt something in my head hurt. and he looked at me, very surprised, and asked how i knew what he was going to say.

i had no answer
sleepaholic
not rated yet Feb 21, 2010
I've had several deja-vu's over the time of my life. I think that the possibility that my brain is simply making a mistake is very plausible -- and sometimes I could reconstruct that it really made a mistake.

On the other hand, since I took a course in Chaostheory, I believe that it is highly likely that randomness doesn't exist at all and that everything is deterministic (but so highly complex, that it appears random). If so, in some weird way the future could already exist, since it is predetermined. I am on some point x_i on the time axis for the complex structure that is reality, and the point x_i+n exists as well, because it is simply the result of the same underlying equation with the time parameter being i+n instead of i.

So all in all I would think that the possibility that a deja-vu is indeed some weird kind of mixing together different time parameters, also exists. However I generally tend to believe that the simpler solutions is the better one.
Nyloc
not rated yet Feb 21, 2010
I think that deja vu is novel event which FEELS somewhat similar to a past event.

I recall looking up while waiting for a traffic light one summer and being struck with a sense of deja vu. On closer reflection, I realized that the sounds of seagulls in the background triggered a memory from my childhood of looking at the sky while listening to seagulls. I had experienced a strong sense of familiarity with the new experience, which felt like I'd had the experience before.

Now, when I have deja vu experiences, I pull them apart, looking for the 'trigger events' which uncover old memories. The more memories I accumulate, the more often I connect new events with past experiences.

I have found all my experiences of deju vu to be similarly structured. Feelings of deja vu remain emotionally powerful, but less puzzling.
SmileysxHearts
not rated yet Apr 05, 2010
I have a question..
Is Flaherty-Craig a scientist?
PLEASE ANSWERR ASAP! :)