Why Do We Get Déjà Vu?

Deja Vudéjà vu (day-zha-voo)

Noun. A feeling of having already experienced the present situation.

Origin early 20th century: French, literally ‘already seen’.

The phrase déjà vu may be French for ‘already seen’, but what does it mean from a neurological point of view? Déjà vu is the feeling that you have experienced a situation before – but haven’t. It can be spooky, but for the most part this is just your brain playing a trick on you. (No, you’re not actually experiencing a premonition from a previous incarnation.)

Scientists aren’t certain about the exact causes of déjà vu and so there are several different explanations. All of them involve some level of miscommunication within the inner workings of the brain, mixing up the present and the past.

The brain can be thought of as being like a biological computer that is constantly making connections between sensations, experiences, ideas and memories. Some neuroscientists think that déjà vu could result from a mix-up between the short-term and long-term memory ‘centres’ in the brain. If an experience somehow skips past the hippocampus (short-term centre) and finds its way into the parahippocampal area (long-term area), the brain recognises it as having happened a long time in the past, even if in reality it is the present.

Other experts have a slightly different theory and think it could actually be to do with an error in trying to remember a past event. It has been suggested that if the brain notices something slightly familiar about a situation (say, a distinctive tree blowing in the wind for example), it will try and make a link between the present experience of looking at a field and one it has stored away. This could lead to a sense of having “already seen” a situation, even if the stored memory actually had little in common with the present.

Despite being something that the vast majority of people experience, the fleeting nature of déjà vu makes it particularly difficult to study.

However, it is known that déjà vu occurs more in those suffering from some neurological conditions, such as temporal lobe epilepsy. This ‘temporal’ part of the brain processes our visual memories, emotions, languages, sounds so could offer scientists clues as to what exactly is misfiring inside the brain to cause the feeling of familiarity.

So if you feel like you’ve been here before, you probably haven’t, just your brain is having trouble separating the present from the past.

So if you feel like you’ve been here before, you probably haven’t, just your brain is having trouble separating the present from the past.
(See what I did there?)

Answer by Sai Pathmanathan and Nick Waszkowycz

Image: Maria Johnson on Flickr

Article by Nick Waszkowycz

June 3, 2014

Nick studied Chemistry at university but decided that the pen was mightier than the conical flask. He decided to set off in search of a way to make his fortune from writing. He is still looking. But like all young men, Nick enjoys football, theatre and debunking conspiracy theorists. He shares his adventure in Berlin at theberlinfiasco.com and writes nonsense about football at tikitakatargetman.com. Follow him on twitter at @nwaszkowycz.

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