Neuroscientists just figured out what causes déjà vu (and it’s not a glitch in The Matrix)

deja vu study fmri conflict dejavu
One of the brain scans created by Akira O'Connor as part of his study.
Researchers may have finally solved the science behind déjà vu and, no, it’s not a glitch in The Matrix.

Déjà vu, for those who haven’t experienced it before (or have you?), refers to the strange sensation that a certain event or experience you have is one you’ve experienced before. Exactly how it works has long been a source of mystery — with one of the main reasons it’s hard to study being just how unpredictable it is.

“The frustrating thing about déjà vu is that, while it’s something most people have experienced, it’s something which happens relatively infrequently,” Akira O’Connor, a lecturer in the School of Psychology and Neuroscience at the University of St. Andrews in the UK, told Digital Trends. “That means that getting the opportunity to measure it is a very difficult thing. We’ve had to rely on people’s retrospective evaluations of the experience.”

That is changing, however. O’Connor and a fellow researcher are using a method to replicate déjà vu in laboratory conditions that works in the majority of people — using a technique for eliciting false memories. This involves giving people a list of words linked by a common theme, like “night,” “dream” and “pillow” — and then asking them whether they had heard the word “sleep.” When they respond in the affirmative, they are then asked if any of the words they heard started with the word “s” (to which they respond negatively), resulting in a confusing sense of déjà vu.

“Déjà vu is characterized by having a false sensation of familiarity, alongside the awareness that that sense of familiarity cannot possibly be correct,” O’Connor said. “It’s a memory clash where there’s false familiarity, together with an objective awareness that it can’t be real.”

Able to recreate the sense of déjà vu in around two-thirds of participants, O’Connor noted that the “strike rate” was good enough for the project to move onto its next phase: scanning the participants with a functional magnetic resonance imaging (fMRI) machine to see which brain regions lit up when the experience took place.

“What we found was that it wasn’t memory-linked regions that are driving déjà vu,” he said. “Traditionally, researchers thought déjà vu was being driven by false memories. What it actually is is that the cognitive control, error-monitoring conflict-checking frontal brain regions are the ones which show greater activity in people reporting the experience.”

O’Connor told Digital Trends that the work was interesting to him as a memory researcher because it demonstrates that memory decision-making has two distinct phases. “There are the memory signals that are coming through all the time, and also an evaluation of those signals that helps us make sense of all of these various brain inputs — combining them into one coherent stream of useful consciousness,” he said.

While all of this might sound interesting in a “lab science” kind of way, however, it does also have a practical application. Déjà vu has often been associated with neurological disorders. Early researchers attempted to discover a link between déjà vu and mental disorders like anxiety, dissociative identity disorder, and schizophrenia. While these researchers failed to find anything substantive, there are most certainly a variety of health and brain conditions associated with déjà vu. For instance, people who suffer from temporal lobe epilepsy will often experience it as part of their pre-seizure aura: the feeling of impending doom that often occurs before an attack. There are also certain dementia patients who will start to experience déjà vu as their symptoms progress and worsen.

But while it may therefore be tempting to therefore suggest that déjà vu is a negative experience, O’Connor’s work suggests this is not the case. “In some ways our work is reassuring,” he said. “It shows that déjà vu is not a memory error. It’s not a problem associated with your memory; potentially it’s a sign of your overall reasoning and cognition being in rude health. It means you’re able to spot a lot of these errors that are happening and carry on as if they’re not happening.”

O’Connor recently presented his findings at the International Conference on Memory in Budapest, Hungary, after which they were first reported on by New Scientist. He is currently working on a paper to be published.

Emerging Tech

This fully autonomous $400 drone folds like a book, follows you like a paparrazzo

Having a drone that could follow you everywhere while taking high-quality images without crashing has been a flight of fantasy. With ZeroZero's Hover 2, not only can you have a fully autonomous 4K selfie drone, you can have it for $400.
Home Theater

Put your home theater to the test with these spectacular Blu-ray releases

What's the point of having all of that awesome home theater gear if you can't breed a little jealousy in your friends and family? We've put together this list of fantastic Blu-rays that have the goods to drop a few jaws.
Gaming

These cheat codes made gaming history

For almost as long as video games have existed, there have been video game cheat codes. Here are some of the most famous cheat codes, including the legendary Konami Code found in dozens of games.
Movies & TV

The best shows on Netflix, from 'The Haunting of Hill House’ to ‘The Good Place’

Looking for a new show to binge? Lucky for you, we've curated a list of the best shows on Netflix, whether you're a fan of outlandish anime, dramatic period pieces, or shows that leave you questioning what lies beyond.
Smart Home

This alarm clock uses targeted light and sound to wake you, but not your partner

The Wake v2 isn't like your typical bedside alarm. Instead, it wakes you by shining a soft light directly into your face, thereby not disturbing the person sharing a bed with you. Pretty smart, huh?
Emerging Tech

Believe it or not, this fire-proof exoskeleton isn’t designed for space marines

A company called Levitate Technologies has developed a fire-resistant upper body exoskeleton that’s capable of lowering exertion levels by up to 80 percent when you carry out manual work.
Emerging Tech

Intel’s new ‘neural network on a stick’ aims to unchain A.I. from the internet

To kick off its first developer conference in Beijing, Intel unveiled the second generation of its Neural Compute Stick -- a device that promises to democratize the development of computer vision A.I. applications.
Emerging Tech

Frogs regrow ‘paddle-like’ limbs when placed in a bioreactor

Frogs have partially regrown amputated limbs thanks to a bioreactor at Tufts University. By jump-starting tissue repair, the bioreactor helped the amphibians regenerate a bigger, more complete appendages than they usually do.
Emerging Tech

Prepare for liftoff: Here are all the important upcoming SpaceX rocket launches

From ISS resupply missions to a host of communication and scientific satellite launches, SpaceX has a busy year ahead. Here's a rundown of some of the company's most important missions slated for the next year.
Emerging Tech

China says it has developed a quantum radar that can see stealth aircraft

Chinese defense giant China Electronics Technology Group Corporation claims that it has developed a quantum radar that's able to detect even the stealthiest of stealth aircraft. Here's how it works.
Emerging Tech

Glass orb packs all the constellations in the night sky into fancy desk ornament

Ever wanted to know more about the star constellations? A stunning new Kickstarter campaign, taking the form of a fancy desk ornament that re-creates the night sky in a glass orb, aims to help.
Emerging Tech

Stronger than steel, thinner than paper, graphene could be the future of tech

Since its discovery, graphene has set the research world on fire. What exactly is it, though, and what could it mean for the future of tech? Here's everything you need to know about what could be the next supermaterial to take center stage.
Emerging Tech

The best drone photos from around the world

Most of today's drones come equipped with high-end cameras, which are quickly revolutionizing the world of aerial photography as we know it. Here are some of the best drone photos from around the world.
Emerging Tech

SpaceX makes rocketry look easy, sticks yet another Falcon 9 landing

SpaceX is due to perform its latest Falcon 9 rocket launch and landing on November 15 from NASA’s Kennedy Space Center in Cape Canaveral, Florida. Here's how you can watch the proceedings live.