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  • This DNews episode is brought to you by Domain.Com!

  • Deja vu: why do I feel like weve done this episode before...

  • Hey guys, Tara here for Dnews - and most, if not all of us, have at some point or another,

  • experienced deja vu. It’s that familiar feeling that youve somehow experienced

  • this moment before - and even though a lot of people claim it has a spiritual basis,

  • perhaps linked to reincarnation - there’s actually a number of scientific theories as

  • to why we experience it.

  • The term Deja vu - which translates toalready seen” - was first coined in 1876 by French

  • philosopher Emile Boirac. And in the years since then, researchers studying the phenomenon

  • - have come up with several different types of deja vu that people experience. In general,

  • though - it’s lumped into one of two categories.

  • There’s associative deja vu, which is the most common type that’s usually experienced

  • by healthy people. And then there’s biological deja vu - which is almost exclusively experienced

  • by people with epilepsy. Often times, they say it occurs immediately before having a

  • seizure. And that medical basis actually makes it a lot easier to study than associative

  • deja vu, which relies entirely on secondhand experiences.

  • For most of the 20th century, researchers relied on the paramnesia theory to explain

  • deja vu. It was an idea proposed by Sigmund Freud, that said the phenomenon was likely

  • caused by repressed memories of a stressful event, that people couldn’t access anymore,

  • as part of their regular memory.

  • It wasn’t until recently, when things like brain imaging became standard, that real scientific

  • research - and not just speculation - was poured into the subject.

  • Nowadays, it’s widely agreed that the medial temporal lobe - the part of our brain involved

  • in conscious memory - plays a significant role in deja vu. This region happens to contain

  • the hippocampus, and more specifically, the parahippocampal gyrus - which is what enables

  • us to determine what's familiar and what isn't. Of course, knowing that this part of the brain

  • is related to deja vu - still doesn’t explain why we experience it. So in attempt to explain

  • that, Dr. Alan Brown from Duke University, concocted something called the Cell Phone

  • Theory, which revolves around the idea of subliminal cues.

  • In his study, he showed a group of students a series of photographs of various locations

  • - none of which they’d actually been to - and then he asked them how familiar those

  • locations were. Just beforehand, though, he flashed SOME of the photos on a screen for

  • 10-20 milliseconds - which is just long enough for their brains to register it, but not enough

  • to actually be consciously aware of what they saw.

  • Sure enough, the images that were subconsciously flashed - appeared more familiar to the students,

  • than ones that weren’t. And those findings, he argued, could be applied to deja vu. The

  • idea being that whenever we feel like weve seen or done something before, it’s because

  • we have - but during that prior experience, our brains were distracted - allowing us to

  • subconsciously process that moment, without actually remembering that we experienced it.

  • Seems solid enough, but that is just one theory, of many. There’s another one, called the

  • Hologram Theory, proposed by Dutch psychiatrist Hermon Sno, that likens humans memories to

  • holograms, in the sense that our brains are capable of constructing whole 3D images from

  • smaller fragments of other memories. So for example, if we were to step into a room that

  • looks similar to a room weve been in before - then our brains might reconstruct an entire

  • false scenario based around that one memory fragment.

  • Again, an entirely plausible theory. But there are some different ones out there - like the

  • Dual Processing theory - which claims that past experiences actually have nothing to

  • do with deja vu, and instead, chalk it up to a delayed neurological response. The idea

  • behind this one, is that because there are multiple pathways through which our brains

  • process incoming information, it’s possible that those pathways may not always synchronize

  • correctly. So any delay between the time it takes for our left brain hemisphere and our

  • right brain hemisphere to process information, could force our brains to register something

  • weve JUST seen, as a previous memory.

  • Of course, like most areas of science, there’s really no simple explanation as to why we

  • experience deja vu. These are just three, of the hundreds of theories out there - and

  • of which seem equally plausible. Still interesting to think about though!

  • And who knows, maybe you guys have some theories of your own. Or at the very least, interesting

  • stories to share. If so, just leave em in the comments below, and as always - thank

  • you guys for watching!

This DNews episode is brought to you by Domain.Com!

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Why Do We Experience Déjà Vu?

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    Eating posted on 2014/11/11
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