Déjà vu throws me off every time. It’s unexpected and unexplainable—and that makes it sort of creepy. Did I subconsciously know this was going to happen? The vague familiarity feels like I’m remembering a dream—but how could I have dreamt something that’s only just happening?
I consider myself a logical person, and in hopes of casting some logic on the mystery of déjà vu, I set out to decode what exactly it is and why it affects us.
What It’s Not
After I started thinking about déjà vu, I realized that we hear about it quite a lot. Movies. Books. Everyday conversations. It’s become a blanket label for a number of tricky-to-explain feelings, which isn’t exactly correct. For example, it’s often (incorrectly) used to describe precognition, or knowing something’s going to happen before it actually happens, like when I just feel that I’m going to get that awesome parking spot, and then I do. (Okay, that’s never actually happened, but if it did, that’s what it would be.)
But the feeling of déjà vu is experienced during an event—not before. Translated from French, it means “already seen,” the past tense of the verb “to see,” and it literally refers to the sensation that we’re experiencing something we’ve already seen—a remembered event—and lasts for approximately ten to thirty seconds. Emile Boirac, a French physical researcher, applied the term to the feeling around the turn of the twentieth century. Boirac had strong interests in psychic phenomena and attempted to peg an otherworldly aspect to déjà vu—connecting it to lost memory, clairvoyance, past lives, and other mystical things.
The Scientific Side
After delving into some published academic research, I quickly learned that researchers do, in fact, have a more concrete understanding of déjà vu. Here’s what’s happening when it strikes: the been-here-before feeling is triggered by a memory we have stored in our brain—but one that we didn’t fully encode in our memory for some reason the first time around, whether we were distracted, very young, or even because we experienced it through a movie, song, or the story of a friend. Whatever the reason, we can’t remember exactly what we’re being reminded of because we only have fragments of that original moment stored. It feels like we’re remembering a dream because we’re trying to grasp a memory without any strong connections or context. That disconnected feeling crops up because we have—at least figuratively—been there before. We just don’t remember it completely.
Okay, okay I hear your skepticism (because my inner cynic is shouting out, too). Sometimes I get déjà vu in a situation that I definitely haven’t been in before, like when I’m traveling somewhere new or doing something for the very first time. That’s because, like I briefly mentioned above, déjà vu can be triggered by a memory that we created from pictures or vivid stories that someone else told us.
Breaking It Down
Freud claimed that we experience déjà vu when we’re spontaneously reminded of an unconscious fantasy—we’re not aware of it, but some of its familiarity seeps into our conscious realm when we’re experiencing something similar. Surveys cited in a study recently published in Scientific American indicate that a majority of us feels it at least once, but recently researchers have tried to explain déjà vu in more specific ways. One scientist, Herman Sno, proposes that we store memories similar to how holograms store information. Unlike photographs, holograms are made up of small pieces, each of which contains all the information necessary to recreate the entire image. The smaller the piece you use to do this, however, the hazier that reproduction of the original image becomes. “It’s rather like convincing yourself that you recognize the person in a blurry security camera picture,” writes James Lampinen, assistant professor of psychology at the University of Arkansas, in the study published in Scientific American.
