What exactly is Deja Vu?

[Kage06]

What is it?

I've read somewhere that it is when the brain processes information rapidly, faster than your conscience thought captures onto a word said, or an image seen. So that when you hear it being said, or you see something, because your mind has already processed it, it feels like you've heard/seen it before.

But what do you guys/girls think?

On another unrelated note, don't you wish you could capture dream ideas, so you never forget them. Last night I had an amazing dream consisting of a song I've been making, and how to finish it off perfectly! Woke up. Gone.

[Vendetta21]

http://en.wikipedia.org/wiki/Deja_vu

http://www.psychologytoday.com/blog/...what-is-d-j-vu

http://www.sciencedaily.com/releases...1118122146.htm

Recognition memory is the type of memory that allows us to realize that what we are currently experiencing has already been experienced before, such as when we recognize a friend on the street or hear a familiar song on the radio. The brain fluctuates between two different types of recognition memory: recollection and familiarity. Recollection-based recognition occurs when we can pinpoint an instance when a current situation has previously occurred.

For example, seeing a familiar man at a store and realizing that we’ve seen him before on the bus. On the other hand, familiarity-based recognition occurs when our current situation feels familiar, but we don’t remember when it has happened before. For example, we see that familiar man in the store, but we just can’t remember where we know him from. Déjà vu is believed to be an example of familiarity-based recognition—during déjà vu, we are convinced that we recognize the situation, but we are not sure why.

Every time I experience Deja Vu it seems to change (prime) my mood so I kinda wonder if the specific thing that happens that we label Deja Vu is incredibly common but what makes Deja Vu special is it's the almost-remembering of a situation where we previously had some thought that felt profound/strange/weird to us for whatever reason. Kinda like trying to remember a word that's on the tip of your tongue but instead your trying to remember a feeling that's on the fringe of your viscera.

[Izzy]

Seems straight forward enough. Pretty much what I was thinking before I entered the thread. A particular moment seems very similar but you don't know why or from where. Perhaps you experienced something very similar in the past or perhaps not.

[MrRubix]

It's really hard to gather data and test for déjà vu because it's such a rare thing and tricky to bring about in test subjects.

For instance, say that I play thousands of video games over a span of many years. I encounter another game and wonder if I've played it before because it seems familiar. This doesn't necessarily feel strange -- there's normally nothing weird about seeing something that tickles a dormant long-term memory.

But déjà vu is a sort of memory triggering that results in a strangeness. It's like triggering a hazy memory that you are pretty sure you've never had, and yet you feel as if you've experienced it somehow in the past. There's a sensation of familiarity but a lack of pinpointable details -- and then it usually fades out of memory pretty quickly and you're unable to re-invoke the sensation of strangeness (similar to how we forget dreams right after we have them).

There's also a concept similar to this called jamais vu -- you can invoke it much more easily. Take any random word (I used to use "moon") and start saying it repeatedly to yourself. Write it out multiple times. Study the word and its spelling/sound as you do. After a certain period of time, the word will appear very strange to you, as if it's not really a valid/correct word. Jamais vu is, in contrast, a feeling of strange newness even though you know (with pinpointable details) that it's empirical/already experienced.

Either way, these strange sensations are likely caused by an intersection between short/long-term memory. We may tickle certain elements of the long-term memory, but through common details that aren't relevant to that memory -- or we may be trying to channel hazy long-term details through something short-term or more easily perceptible.

[Kage06]

Jamais vu is something I encounter quite frequently in that case. Where I look at a word and wonder if its right, or how it could make sense, then suddenly, it'll make sense again.

Yeah, that video game point makes sense, because you wouldn't get that weird feeling, yet with de-ja vu, your pretty sure you've heard/seen it exactly as it was said/seen before.

This picks up on what I mentioned about the brain at times working faster than you consciously notice:

"Another theory being explored is that of vision. The theory suggests that one eye may record what is seen fractionally faster than the other, creating the "strong recollection" sensation upon the "same" scene being viewed milliseconds later by the opposite eye.[4] However, this theory fails to explain the phenomenon when other sensory inputs are involved, such as hearing or touch. If one, for instance, experiences déjà vu of someone slapping the fingers on his left hand, then the déjà vu feeling is certainly not due to his right hand experiencing the same sensation later than his left hand considering that his right hand would never receive the same sensory input. Also, people with only one eye still report experiencing déjà vu or déjà vécu (a rare disorder of memory, similar to persistent déjà vu). The global phenomenon must therefore be narrowed down to the brain itself (i.e., one hemisphere being late compared to the other one)."

[ledwix]

Why does jamais vu happen? Is it because the words we say are only absent-minded placeholders for actual emotions we're feeling, and that words themselves are all just arbitrary combinations of sounds that can come out of a human mouth? So in a sense, is it that we don't think about the mechanics of words as much as the feelings associated with them?

Well, the same effect works for individual letters. I took a just-for-fun online quiz many months back that asked to name a bunch of words that started with q. It was only like an 8 minute quiz, but toward the end, I started to question whether "q" was actually a letter. It kept looking so weird and foreign. Why was there this backwards "p" all over the page, why wasn't it just a regular "p," and why in the world would it be pronounced like "cue"?

/*Also, I find it funny that "combinations" will give you a spelling error on this site, but "combos" does not. That seems intentional given the nature of the site.*/

[MrRubix]

Another word I got to easily kick in the jamais vu the other day was "second." It's easier to kick in, it seems, when the sound of the word differs from the spelling.