Ever get that feeling that you’ve done something or been somewhere before? It doesn’t seem possible, yet at that moment it’s very real and a little unsettling. That’s déjà vu, and it’s a pretty common occurrence for many people. Ask a group of your friends if they’ve ever experienced it and most (if not all) will say yes, even if they can’t recall what happened. However, despite being a recurring phenomenon, we don’t understand how or why it happens. At least, we didn’t.
In 2012, a study was published in Consciousness and Cognition by cognitive psychologist Anne Cleary that delved into the déjà vu experience. Cleary had been looking into déjà vu for years before she uncovered what she now believes is an explanation for the occurrence. It takes a lot of the magic out of the phenomenon, but it makes a good point.
Cleary has suggested that when a person experiences déjà vu, they’re doing something that triggers a memory which was similar in some way. Their brain isn’t able to remember what the past event was, and therefore there is just a lingering sense that what’s happening at that moment is eerily familiar.
To test whether her understanding of déjà vu had any weight, Cleary set up an experiment that identified whether the feeling of familiarity could be “planted” or not. It involved a collection of virtual reality scenes where subjects would move through different settings, unknowingly creating a memory that Cleary would later test. After the participant had completed this part of the experiment, they would repeat it, but with a different collection of scenes. Here, the settings were the same spatially, but not aesthetically, which Cleary hoped would trick the person’s brain into believing they could predict what was coming next.
Both sets of virtual scenes involved a variety of turns, and this is where Cleary was looking to test whether her participants experienced déjà vu. Before the final turn, she asked them what they thought they would see, and whether they felt like they knew the answer. It was the second of these two questions that was most important, because it focused on the feeling that the participant had experienced it all before – aka déjà vu.
The outcome of the experiment was that half of the participants going through both of these simulations reported a strong sense of déjà vu, but weren’t necessarily correct about what they were going to see.
In response to this, Cleary said that while they couldn’t remember the prior scene, [their] brains recognize the similarity.” When that feeling came through, it resonated as déjà vu because the scene felt familiar to them, but they had no idea why.
There you have it, the truth of déjà vu. Or maybe not, we don’t know for sure. We’re still holding out hope that there’s another more mystical explanation for it, but we might be pushing our luck with that one. Cleary’s hypothesis seems pretty believable.