According to Giordano, although those two aforementioned pathways usually work in a harmonious way, they can stop working. "Sometimes they become 'out of sync'," he says. The 'fast' pathway responds strongly, and the 'slow' pathway only catches up fractions of a second later. It's an infinitesimal slowdown, but it means your memory can't determine whether this has happened before or not.

This is called a mismatch, and it explains why something that has never occurred can feel like it has. "Networks of the temporal lobe and frontal cortex 'interpret' this mismatch and we experience this as as a memory playing out in real time, which makes it seem as if we're 're-experiencing' something that is actually new," says Giordano. A study in Frontiers in Psychology in 2013 found déjà vu comes from a memory conflict in the brain, and the feeling persists while the brain tries to figure out what's real memory and what's not.

"Because déjà vu often occurs suddenly — with no warning — and is fleeting in duration, it’s incredibly hard to study in a clinical setting in a healthy population," neuroscientist & holistic wellness expert Leigh Winters, M.A. M.S. tells Bustle.

But, like Giordano, Winters agrees that it does come down to how the brain processes memory and the occasional mismatch, making it a cross between a memory error and a "neurological impulse glitch." You may also be more familiar with the situation that sparks déjà vu than you think. "It might be possible that déjà vu occurs when you detect familiarity, stimulating the rhinal cortices, but don’t activate the hippocampus, which helps you recall more concrete memory details," says Winters. "Some propose that this is why déjà vu has that eerie feeling of semi-remembering, or feeling like you’ve been there before but can’t seem to put your finger on it." Because, let's be honest, who hasn't felt a sense of eeriness when it comes to déjà vu?"Because déjà vu often occurs suddenly — with no warning — and is fleeting in duration, it’s incredibly hard to study in a clinical setting in a healthy population," neuroscientist & holistic wellness expert Leigh Winters, M.A. M.S. tells Bustle.

But, like Giordano, Winters agrees that it does come down to how the brain processes memory and the occasional mismatch, making it a cross between a memory error and a "neurological impulse glitch." You may also be more familiar with the situation that sparks déjà vu than you think. "It might be possible that déjà vu occurs when you detect familiarity, stimulating the rhinal cortices, but don’t activate the hippocampus, which helps you recall more concrete memory details," says Winters. "Some propose that this is why déjà vu has that eerie feeling of semi-remembering, or feeling like you’ve been there before but can’t seem to put your finger on it." Because, let's be honest, who hasn't felt a sense of eeriness when it comes to déjà vu?

"It has been reported that some with epilepsy experience this phenomenon right before a seizure — specifically when seizures begin in the MTL [medial temporal lobe], an integral brain region for long-term memories and events," says Winters. "By isolating neuronal changes in the rhinal cortices, it’s thought that déjà vu is largely caused by electrical impulses gone awry." This doesn't mean you should run to the nearest neurologist the next time you experience déjà vu. If you have an epilepsy diagnosis, though, your déjà vu may be a warning sign of a seizure beginning.

"About 60 to 70% of people report having déjà vu, but it's likely that it occurs more commonly, and déjà vu occurrences are generally more common in younger people," Giordano says. We experience the most déjà vu between the periods of 15 and 25.

While this isn't to say that as you get older your chances to experience déjà vu will vanish, you should definitely enjoy it when it appears. It really is a remarkable phenomenon that shouldn't just be dismissed.

The more stressed people are, the more they report experiencing déjà vu. This could be because when you're under a lot of pressure, or processing a whole heap of information at once, your brain is more likely to 'glitch' and have difficulty lining up memory with real life.

Although the chances are slim that you'll find a neurologist who agrees with this assessment, if you believe in past lives — a belief you're completely entitled to — this "reason" is worth noting.

"Beyond neuroscience, many in the field of psychology have their own thoughts about what’s going on when we experience this feeling that we’ve already seen or experienced a situation," says Winters. "For example, some parapsychologists think déjà vu is connected to something we experienced or were connected to in a past life. But one thing's for sure — as brain imaging techniques improve, so will our understanding of déjà vu."

"Déjà vu is actually a good sign, and seems to reflect the brain's ability to process memories at different levels and at differing speeds," says Giordano.

Ultimately, déjà vu is further proof that the human brain is amazing. If a "mismatch" or a "glitch" can result in something so extraordinary, it's a true testament to just how remarkable it is. So the next time you experience déjà vu, no matter how eerie it may feel in the moment, embrace it for the fantastic "glitch" it is.