Ask LH: What Exactly Is Deja Vu (And Should I Worry About It?)

Dear Lifehacker, I've been experiencing deja vu more often lately -- you know, that odd feeling where you can swear you've been somewhere before or had the same conversation with someone but really didn't. Is this bad? Should I be concerned? My friend says she used to get it a lot but hasn't for years. Should she be concerned? Is this just a glitch in the Matrix? Thanks, Seeing Glitches

Image: Modified from istolethetv.

Dear S.G.,

Déjà vu really is an uncanny feeling. The term in French literally means "already seen" and that's exactly why it's so unnerving: It really feels like you've already experienced a very specific event or been somewhere, even though you haven't (or, at least, you don't think so).

Further complicating the matter, there's no consensus yet on what exactly causes this phenomenon, though there are a lot of theories. Psychology Today points out a study that suggests that deja vu is just an extreme reaction of your brain's memory system when encountering things with lots of familiar objects just set up a little differently (for example, when you're in a restaurant configured almost identically to one you've been in before, you can get a powerful feeling of familiarity).

Scientists have found a possible cause for deja vu occurances in the brain. Popsci reports that mice lacking some specific receptors in the hippocampus area of the brain have responses similar to deja vu, so the theory is that deja vu can be just a temporary disorientation in the hippocampus, which is the part of the brain responsible for sense of direction and forming new memories.

To answer your questions, though, deja vu appears to be harmless for most people (as much as 70 per cent of the population has reported experiencing it, according to Discovery's How Stuff Works), with higher rates of occurence in people age 15 to 25 -- so your friend's decreased deja vu experiences should be fine, too.

However... deja vu has also been associated with temporal-lobe epilepsy (one story shows a woman who had 20 years of deja vu episodes before finding out she had epilepsy). So, not to alarm you, but if you experience frequent déjà vu, you may want to see a doctor.

Finally, have you been feeling anxious or stressed out lately? Wikipedia mentions a link between deja vu and anxiety and you'll find lots of stressed-out people on health forums who also say they've been experiencing more deja vu. So our Lifehacker tip for trying to stop deja vu from happening, if you want to, is good old stress and anxiety reduction.

Cheers Lifehacker

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    Great article Melanie!

    Although I have this strange feeling I've read this before somewhere.... :-p

    Personally, I like the idea or theory, that it's a past life memory! #]

    I used to get this quite a lot. Not so much anymore. But when I do, more often than not I also have the feeling of "remembering" getting Déjà vu, on top of the situation itself. Déjà vu within Déjà vu. It's an extremely disorienting feeling.
    From all the things I've read though, I like the theory that for one reason or another your brain is encoding the memory twice: It stores stuff in your memory once, and then when it decides to store the same stuff a second time it's already in there, so you "remember" it happening before.

      Oh thank god it's not just me! I call this 'compound' deja vu, or maybe 'inception' deja vu would be a better term!

      Deja vu that I've had deja vu that I've had deja vu about something! Freaky.

    Recently diagnosed with epilepsy - definitely a good explanation for the Déjà vu that I had for years before!

    Hippocampus... lol...

    Damn I can't believe it, but I just had Déjà vu of getting Déjà vu of reading this Déjà vu article.

      We must go deeper....

    That image is a total doppelgänger of John from The Grates

    it's a glitch in the matrix?

    I'm not kidding, but I've had dreams of exact enviroments, and months later the dream has come true, only for like 10 seconds, but it's a true Déjà vu :/

    I believe it's more than scientific! I've had many a deja vu but have actually quoted what friends would say or do before it has happened.

    Can't say that's the hippocampus :)

    don't worry - the matrix will reset itself with an updated version soon and then deja vu will be a less common phenomenon - bless those robot's hearts for making life so much better for us...If only they could get the taste of Chicken right...

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