• Question: what causes deja vu and why does it occur?

    Asked by 439erbb39 to Jen, Hephzi, Imogen, Jennifer, Tom on 10 Mar 2015. This question was also asked by abbix.hardy:D.
    • Photo: Jen Machin

      Jen Machin answered on 10 Mar 2015:

      There are a few theories about this, but it seems to happen when something goes a little bit wrong in our memory system. Normally when you remember something, your brain will recollect it (so you’ll remember an experience where a particular thing happened) and you will recognise it as familiar (so you know it has happened before). When you have deja vu, it seems like the familiarity part gets activated, but the recollection part doesn’t – this is why you feel like a situation is familiar but you can’t remember why. It’s a very strange feeling! 🙂 It’s also quite a difficult thing to study because we don’t know when someone is going to experience deja vu, so it’s harder to bring them into the lab and put them in a scanner whilst it’s happening to see what’s actually going on in the brain.

      I hope that answers your question 🙂

    • Photo: Thomas Barrett

      Thomas Barrett answered on 11 Mar 2015:

      There seem to be several possible reasons (of which I will go through a couple here).
      1) Dual processing – when two usually in sync things temporarily fall out of sync with each other. So the familiar feeling is due to your brain grabbing a similar memory to what you are doing.
      2) Nerves not working properly. This is where your brain either misfires and you recall something or the information your brain receives arrives at slightly different times so even if you’re only seeing it once it feels like you have seen it already as part of it reaches your brain faster than other bits.
      3) Because it is similar to what you have done before and your brain realizes that.

      Watch this video for more.

Comments