A few weeks ago, I was halfway through a conversation with a friend at a coffee shop when it hit me: the coffee, the table, the phrase I’d just said—it all felt eerily familiar. Not in a “we always meet here” kind of way, but in a this moment already happened in exactly this way sort of way. My stomach did a little flip. My brain felt like it skipped a frame. I paused mid-sentence, wide-eyed, and said, “This is so weird, but I swear we’ve had this conversation before.”
We hadn’t. At least, not according to my friend or the space-time continuum.
That, of course, was déjà vu—a brief, disorienting moment where reality feels like a rerun. And if you’ve experienced it (most of us have), you know it feels equal parts uncanny and magical. But what actually is déjà vu? Is it a brain hiccup, a sign of a hidden memory, or something more layered?
Psychologists have been asking that question for decades, and while we don’t have a single answer, we do have a compelling collection of theories that suggest it’s not just a glitch. In fact, it may reveal something profound about how we store, retrieve, and sense-check our memories—and how we create a sense of self through time.
First, What Counts as Déjà Vu?
Déjà vu is a French term meaning “already seen.” It describes the unsettling and brief sensation that a new experience is oddly, inexplicably familiar.
But it’s not just recognizing a place or person. It’s a more elusive feeling—like the script of a moment has already played out, even though you know it hasn’t. And what’s weirder? It’s usually fleeting, hard to explain, and nearly impossible to reproduce on command.
Researchers define it as a false sense of familiarity, occurring in the absence of actual memory. That is: you feel like you’ve been here before, but there’s no concrete recollection backing it up.
Who Gets Déjà Vu—and How Often?
You’re not imagining it: déjà vu is common. In fact, research shows that nearly 97% of people experience it at least once, and about 67% have it happen on a regular basis.
Interestingly, it seems to peak during young adulthood—especially between the ages of 15 and 25—and decreases with age. Some experts believe this might be due to changes in memory sensitivity and how we process new experiences as we get older.
And yes, people who travel often, read a lot, or frequently encounter new environments are more likely to experience it. Chalk that up to more sensory overlap and memory activation.
So… What Causes It?
Here’s where it gets really fun—and a little trippy. There are several theories, all backed by different branches of cognitive science and neuroscience. No single one explains every instance, but taken together, they create a compelling portrait of what might be happening.
1. Dual Processing (Split Perception)
One of the oldest and most widely accepted theories is that déjà vu occurs when the brain accidentally processes the same information twice. The idea is that your brain takes in a scene or moment, but due to a brief delay—just milliseconds—it processes it as both “new” and “familiar” at the same time.
Think of it like hitting the “refresh” button on a webpage that was already loaded.
You’re seeing something, your brain is registering it again almost immediately, and because that second perception arrives so fast, it feels like a memory.
2. Memory Mismatch (The Familiar Stranger Effect)
Another explanation suggests that déjà vu occurs when a current experience closely resembles a past memory—enough to trigger a vague feeling of familiarity, but not enough to recall the original moment.
So you may not remember the when or where, but your brain lights up with a fuzzy sense that this has happened before.
Imagine walking into a room that’s lit a certain way, with music playing that vaguely resembles a song you loved in college, and a scent in the air that’s close to your grandmother’s house. Boom—your brain stirs up a cocktail of almost-memory that feels eerily real.
3. Neural Circuit Glitch (But Not the Scary Kind)
Let’s address the word “glitch.” Déjà vu can result from a minor, harmless misfiring in the temporal lobe—specifically in the hippocampus, the region of the brain that handles memory formation and retrieval.
This theory gets some of its roots from studies involving epilepsy patients. In some cases, people with temporal lobe epilepsy report experiencing intense déjà vu right before a seizure.
But don’t worry—experiencing déjà vu doesn’t mean you have epilepsy. For healthy brains, these occasional misfires are thought to be harmless. In fact, some researchers think they’re a sign of a healthy memory-checking system. It’s like your brain doing a little quality control audit—and sometimes flagging a false positive.
4. Dream Memory Activation
Ever had a déjà vu moment and thought, Wait… did I dream this?
You might be onto something. Some psychologists believe that déjà vu could be linked to dreams—especially those we don’t remember fully but that left behind visual or emotional imprints.
Your current experience might echo a dream fragment (a hallway, a conversation, a lighting pattern), triggering that eerie sense of familiarity without a tangible source.
It’s less about prophetic dreaming and more about the complexity of how dreams encode information—somewhere between imagination and memory.
So… Is It Just a Brain Glitch?
Let’s reframe that. It might start as a brain misfire or momentary processing hiccup, but psychologists now believe déjà vu serves a deeper purpose.
It’s a metacognitive signal—your brain checking in with itself about memory accuracy. Instead of being a bug, it might actually be a feature, letting us know when there’s a mismatch between memory and perception.
That’s kind of poetic, right? Déjà vu isn’t just a mysterious loop in the matrix—it’s your brain doing its best to double-check your internal map of reality.
How to Make Sense of Your Own Déjà Vu
While déjà vu is, by nature, fleeting and hard to pin down, you can pay closer attention when it happens. Here are a few things to observe the next time it strikes:
- Context: Where are you? Who are you with? What’s happening?
- Emotion: Do you feel calm, unsettled, excited?
- Timing: Does it happen when you’re tired, stressed, or traveling?
- Sensory Details: Is there a smell, song, or lighting cue that feels familiar?
You don’t need to journal every episode, but noticing patterns may help you understand what triggers your brain’s familiarity radar.
The Cultural Layer: Why Déjà Vu Feels So Meaningful
There’s also the fact that we assign meaning to déjà vu. Some spiritual traditions view it as evidence of past lives, alternate dimensions, or intuitive knowledge. And while science doesn’t confirm those explanations, it also doesn’t entirely disprove them. The brain is complex. The mind even more so.
What’s clear is this: when déjà vu strikes, most people pause. We lean in. We wonder. We feel, if only for a second, like we’ve stepped outside of linear time. That moment—strange as it is—reminds us that our minds are always working behind the scenes, stitching together the past, present, and imagined in ways we’re only beginning to understand.
The Beauty of a Brief Brain Glitch
So, is déjà vu just a glitch? Maybe. But if so, it’s the most poetic glitch we’ve got.
It reminds us that memory isn’t a file drawer. It’s a living, breathing system—complex, intuitive, and sometimes prone to surprise. And in a world where everything is moving fast and predictably, déjà vu slows us down. It taps us on the shoulder and says, Pay attention. Something about this moment matters—even if you’re not sure why.
And maybe that’s enough. Maybe the real magic of déjà vu isn’t what it reveals about the past—but what it says about how we’re experiencing the present.
Let it be weird. Let it be wonderful. Let it be a glitch worth noticing.
