Naked Science Forum

Life Sciences => Physiology & Medicine => Topic started by: paulat on 04/01/2007 04:22:33

Title: What is deja-vu?
Post by: paulat on 04/01/2007 04:22:33: I might have asked this already (boom boom), but what's deja-vu, and what causes it?
Title: Re: What is deja-vu?
Post by: iko on 06/01/2007 12:44:16: "deja vu" is French and means "already seen".

The term "Deja Vu" refers to the illusion of having already experienced something actually being experienced for the first time.

I just knew the meaning,
no idea about the causes...

ikod

you may have a look at
one of the 'deja-vu"
debates on-line:

http://allphilosophy.com/topic/33

...I really think I've seen already some of this stuff...
Title: What is deja-vu?
Post by: drkev on 13/01/2007 03:08:53: There are actually 3 types of deja vu called: Deja vecu, Deja senti and Deja visite.

Deja vecu is the one which most people mean when they mention deja vu, deja vecu is a more accurate term because it involves feelings involving senses other than just sight.

Deja visite is something I have experienced before and it was very spooky. This is where the person has explicit knowledge of a new place. i.e they know their way around a town they have never visited before but they know that this simply isn't possible.

I have had deja visite before and it was very scary. I was in a town that I have never visited before in my life and I knew exactly where everything was and how to get from a to b. This should not have been possible and I have no explanation for how I felt.

Taiminen and JÃ¤Ã¤skelÃ¤inen (2001) speculate that dÃ©jÃ vu occurs as a result of hyperdopaminergic action in the mesial temporal areas of the brain whilst other scientists belive that deja vu occurs as a result of the mis-timing of neuronal firing in the brain so the brain believes that it is receiving a stimulus for the second time when it is actually experiencing the same experience twice.

Then you have the nutters who believe that deja vu is a spiritual past life event but have no evidence to back up their claims!

If there genuinely were psychics or such like then James Randi would be very poor!
Title: What is deja-vu?
Post by: chris on 13/01/2007 12:22:49: Good answer Kev.

It's likely that when we know we know something it's a different part of the memory encoding process telling us that than the process that stores the information itself. One could liken it to the index card system in a library. If there's a card in there, you know that book is on the shelf somewhere, without having to physically access the book.

Deja-vu occurs when an index card ends up in the file but there's no book on the shelf. You're experiencing something for the first time but the brain thinks it's not novel. This triggers the recognition / familiarity reflex (like that little twinge of "oh I know this" when you're asked a quiz question), only in this instance it's not appropriate.

I tend to get this when I am sleep deprived. A run of late nights, or accumulated lack of sleep, provokes spontaneous and sporadic sensations of familiarity.

Chris
Title: What is deja-vu?
Post by: drkev on 13/01/2007 18:48:12: The "oh I know this" when you're asked a quiz question is known as Presque vu
Title: What is deja-vu?
Post by: DrN on 13/01/2007 20:19:50: why is everything in french?
Title: What is deja-vu?
Post by: drkev on 13/01/2007 20:23:27: Because the original phrase was invented by Emile Boirac in L'Avenir des sciences psychiques which is a book he wrote about the future of psychic sciences.
Title: What is deja-vu?
Post by: iko on 14/01/2007 16:55:28: Quote from: fishytails on 13/01/2007 20:19:50
why is everything in french?

To make us study and learn a bit of French
language and rush to Paris for 1 week!!!
Bliss

VoilÃ
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