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Deja vu: why do I feel like we’ve 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 you’ve 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 to “already 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 we’ve 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 we’ve
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 we’ve 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!