“I feel like we’ve been here before…”, “Why do I already remember doing this?” or “What’s that 2006 banger by Beyoncé called?”
Déjà vu. That weird feeling you get when it seems like you’ve experienced something before (and also the name of that great song).
It can be pretty creepy, especially when you know you definitely haven’t done said thing or been in said place previously.
I mean, it doesn’t even sound like something that should be a real experience, more something that should be in the plot of sci-fi film (shout out Denzel Washington).
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And while experts can’t quite confirm a solid reason why it happens with science, they do have some very real theories behind why people might experience déjà vu.
An article on Healthline reviewed by Professor Debra Rose Wilson lays these out.
Minor brain circuit malfunctions
One theory suggested is that your brain basically has a little ‘glitch’ and there’s a bit of a mix-up when both the part of the brain that tracks present events and the part recalling memories are both active.
It’s not generally a cause for concern unless it happens super regularly, so keep a note for your GP.
It is also thought it could be down to another kind of ‘malfunction’. This could be to do with how you absorb information and it being that there’s been a shortcut taken with memory storage.
So, you might feel like you’re retrieving a long-ago memory when it’s actually something that happened in the last few seconds.
Or, there’s a theory of a malfunction with ‘delayed processing’. Basically, you observe something but the info goes into your brain along two separate routes and maybe one of them gets there faster than the other. Therefore, your brain may ‘read this single event as two different experiences'.
Memory recall
Others reckon déjà vu is down to how you process and recall memories.
Research from Anne Cleary, a déjà vu researcher and psychology professor at Colorado State University, generates some support for this as she’s found evidence to suggest it can happen in response to an event that resembles something you’ve experienced but don’t remember.
You might not be able to recall it for some reason, but your brain still knows you’ve been in a similar situation.
Maybe it happened in childhood, or you can’t recall it for some other reason.
Split perception
This theory suggests it happens when you see something two different times. Perhaps the first time, you were a little distracted or it was in the corner of your eye.
So when you have a proper view of it, your brain may recall the previous perception and you’ll feel like it’s two different events.
When in reality, it’s ‘just one continued perception of the same event’.
Memory
In general, experts agree déjà vu most likely relates to memory in some way. Perhaps, you have experienced something similar before and just can’t remember it.
But either way, it typically isn’t something to worry about. However, if it happens regularly, it may be a sign of being tired or under stress or, a symptom of a health condition.
NHS opinion
A document from Oxford Health NHS Foundation Trust explains feelings of déjà vu isn’t anything ‘strange’.
It explains: “Our mind often takes incomplete pictures of events (it cannot remember everything). Sometimes a smell, a sound, light falling on a tree in a certain way will be enough to trigger this partial memory which our mind then tries to fit to the existing situation.”
However, for some people, déjà vu comes alongside their epilepsy.
The NHS explains that simple partial (focal) seizures can cause a feeling that events have happened before and can be a ‘warning’ that another type of seizure is about to happen.
Jess Battison