Déjà vu – Sound familiar?

Ever had a feeling that something has happened before even though you know it can’t possibly be true? Are these feelings your memories of a past life? Are you psychic? Is there a glitch in the matrix?

There’s definitely something eerie and mysterious about déjà vu. But everything can be explained by science, right?

Actually, déjà vu is a poorly understood phenomenon and there are many different theories about how and why déjà vu occurs.

Déjà vu – Just like a scene out of Groundhog Day. Source: Alex Ranaldi via Flickr.

Déjà vu is really tricky to study because it is a subjective and random experience that can occur at any time – hence the lack of consensus on why it happens.

France gave us déjà vu

Déjà vu is a French word, which literally translates into “already seen”. People describe the experience as a feeling of familiarity with a particular situation, while at the same time knowing that the situation is completely new. For example, imagine you walk into a store that you have never been to before, but for some reason you just can’t shake the feeling that you have been in that exact spot before. Or perhaps you overhear a conversation which you swear you heard just yesterday. Creepy, right?


Déjà vu: Mind tricks or good for your health?

One theory suggests that déjà vu is simply a form of familiarity-based recognition. Familiarity-based recognition is a feeling of familiarity with a place, something or someone due to particular features you are familiar with from a different situation.

This all sounds pretty confusing, but at its core, familiarity-based recognition could be something like: You go on a holiday to Hawaii and you feel like you’ve been there before even though you know this is your first trip outside of Australia; it feels familiar because of the scenes of Hawaii you saw from all those Getaway episodes you watched.

This theory is supported by the fact that people who travel more or watch TV and movies more or are more able to recall their dreams also experience déjà vu more frequently. Scientists argue that these activities increase the store of familiarities a person has, so déjà vu is more likely to occur due to familiarity-based recognition.

Have you really been here? Or is your brain lying to you? Source: Dhilung Kirat via Flickr.

Another theory suggests that déjà vu is actually a sign of good memory function. So the more often you get déjà vu, the better your memory is – seems counterintuitive doesn’t it? Well, Japanese researchers found that people who experienced déjà vu were younger and more educated than those who did not experience it. They used this information along with other memory-related measures to conclude that, as a person ages and their memory deteriorates so does the frequency of déjà vu.

An unpublished study builds on this theory, suggesting that déjà vu is a process of the brain checking its memories to see if there is any error, and thus is a sign of healthy brain function. This potentially explains why the frequency of déjà vu decreases as you age and your memory function deteriorates, so does. However the proof is far from concrete due to the difficulty of studying déjà vu – hence the many theories floating around.

Of course, these theories aren’t even the tip of the iceberg – but we’re not going near the “alien abduction” déjà vu theories.

Is this who’s responsible for déjà vu? Spoiler alert: no. Source: Yasir999 via Wikimedia.

Who knows, maybe we will solve the mystery that is déjà vu, or maybe it will remain one of life’s curious unknowns.

So, what do you think causes déjà vu?


8 Responses to “Déjà vu – Sound familiar?”

  1. Jasmin Hartel says:

    Thanks everyone, so glad you all enjoyed this post!

    Siân – that’s a very interesting theory! I wonder if it is backed up by any studies? It’s strange to think that your brain is possibly having a bit of a glitch when you experience deja vu.

    Jennifer – I have definitely been hyper-vigilant about deja vu since I wrote this post. It makes you wonder how much your brain plays tricks on you!

  2. Jennifer Feinstein says:

    Super interesting blog post topic, Jasmin! Love the clever title and really well organised and explained. I laughed when I read that one theory states that deja vu happens more the better your memory is! It definitely is counterintuitive, but it makes sense. I haven’t experienced deja vu for awhile, but am curious if it will happen to me soon now that I have read this blog post :).

  3. Soumya Mukherjee says:

    What a thoughtful blog ……. I myself have experienced this ….. it definitely feels weird when these kind of thinks happen. Thanks for the post.

  4. Claudia says:

    Those seem like very valid points. It’d be interesting to see if I still get affect by deja vu when I’m older!

  5. Siân says:

    I cannot claim this theory, it is a friends, but I find it interesting. He proposes: when our brain is processing a moment to our short term memory storage that sometimes it accidentally directs to long term memory storage first. Perhaps only for a split second, but enough to feel we have experienced the sensations of that particular moment before!

  6. Raveena Grace says:

    I really enjoyed reading this blog, such an interesting topic and I liked reading about the different theories of deja vu. I’ve had deja vu happen to me so many times so I hope it is a sign of good memory function 🙂 Really great read!

  7. Jasmin Hartel says:

    Thanks Heather! Deja vu is definitely a very weird feeling – I’ve even felt deja vu in dreams! Although it is pretty cool that something so strange is also a universal human experience.

    It’s hard to figure out the exact cause of deja vu because everyone experiences it differently and most studies rely on self-reported deja vu. So at least for now the studies aren’t too reliable. But who knows, maybe one day they will figure it out!

  8. Heather says:

    Thank you for your blog, such an interesting topic!

    I’ve had some really intense deja vu experiences when it doesn’t just feel like I’ve been somewhere once before, but it feels like I’ve been there and experienced the deja vu a hundred times before!

    I have no theories of why it happens! But I’d love to know if anyone is able to definitively find out why!