You’re on the sofa, a drink in your hand and a TV programme playing out in front of you. You’re halfway concentrating on the TV, engaged in a conversation with the person sitting next to you. The door opens and you turn over your shoulder to look. Your friend is in the doorway. “Any of you want anything?” he asks. Something clicks in your brain - I’ve seen this before. Did I dream about this? Your sofamate pauses before responding, “Are there any chips left?” I knew he was going to say that, you think. How is this happening?
It carries out for another 30 seconds - you’re experiencing increasing levels of disbelief as an ordinarily mundane conversation plays out in front of you. Slowly, the prescience, the familiar feeling, fades. You tell your friends about your brief brush with the infinite - the fact that you were granted divine foreknowledge of their whole conversation. They seem somewhat underwhelmed, to your consternation.
You have just had a bout/case/episode of déjà vu. Statistically, about 97% of the people reading this are nodding along to this description - recognising this experience (ironically). That means about 3% of readers have missed this wonderful quirk of human existence. For those of you unfamiliar, déjà vu, (French for “already seen”) is a psychological sensation where one feels that they have previously experienced the current situation.
ORIGINS OF DEJA VU
There are many explanations around the origin of déjà vu. The one that I find most convincing is that it’s a false-positive in the recognition pathway. In normal circumstances, you experience something through your physical senses: your eyes perceive the scene in front of you, and the images get passed to the medial temporal lobe to see if you have experienced this before. This is a pre-conscious step - it happens separate to, and ahead of, your conscious thought/Cartesian observer/homunculus registering what is happening. If you’ve seen it before - if it matches the databank of previous observations, the medial temporal lobe gives the scene/person/location a thumbs up - yep, we know this. By this point, your frontal cortex - the conscious, thinking part - kicks in and you’re “aware” of what you’re looking at.
But imagine you get a false positive. Your medial temporal lobe passes a positive recognition check back up the pathway - we’ve seen this one before. Your frontal cortex then watches the scene unfold in front of it, accompanied by a strong sense of familiarity from the medial lobe: I’ve seen this before… therefore I must know what’s about to happen, what’s about to be said. But how? Maybe I saw it in a dream? You begin to realise that, familiar or not, you can’t predict what’s happening and that there’s something off about the recognition you feel. After a period of time, usually less than ten seconds, normalcy asserts itself - perhaps the check is repeated in the medial temporal lobe - and the familiarity flag is discarded. But the unsettling feeling can last a lot longer.
RELATED MENTAL PHENOMENON
Deja vu has a reciprocal.[1] A Joker to its Batman. “Jamais vu” is a complete lack of familiarity experienced when viewing a scene or situation that is known to be familiar. A false-negative in the recognition circuit. A classic example comes in the double-take upon writing a common word that somehow feels… wrong? It can, in fact, be induced by writing the same word over and over. When you’re writing it for the forty-seventh time, it will probably start to feel a little unreal.
Jamais vu is less well known, and rightly so - the boundaries of this experience are much harder to define. How can we separate jamais vu from simple forgetfulness? It can also be more easily induced: a simple experiment involves writing out a common word 50 or more times. By the time you get to the end, you’ll start to doubt whether the word itself is real.
Jamais vu has a bigger brother. This experience in extreme manifests as Capgras delusion. Originally known as the “illusion of Doppelgangers”, Capgras delusion usually results from traumatic brain injury. In patients with this condition, the familiar feels alien. They become convinced that their loved ones have been replaced by identical clones. In this instance, there is no “recognition flag” from the medial temporal lobe. They can look at their loved ones and see every quirk, behaviour and action that they expect. But when run against the medial temporal’s check - have I seen this before? - they get no verification. The conclusion is clear - I do not recognise this person. The only logical conclusion is that this is not the person they love but a flawless simulacrum. Capgras' delusion is heartbreaking. Deja vu is harmless. But both come down to some issues in internal wiring.
ENJOYING THE RIDE
Everything that happens to us - all our experiences and interactions, and the resulting memories of them - come from electrical signals interpreted by a densely packed bundle of cells wrapped in fat. Science. Philosophy. Reaction videos. It all comes from a few pounds of meat having a profoundly detailed dream. So is it any wonder that things go wrong occasionally?
Have you ever drunk a can of Coke too quickly, then burped and had the carbon dioxide make its way out your nose by mistake? It’s a strange, unfamiliar sensation -an unexpected burning that takes you off guard and often causes an involuntary shudder. As a teenager, I discovered that you can deliberately redirect the carbon-dioxide soda-burp up your nose anytime you want. It just takes a little bit of deliberate management of the airways. Now I seek out. I drink my sodas too quickly, delighting in the opportunity to experience something slightly out-of-the-ordinary. There’s no lasting effect, no negative consequence, just your body going slightly wrong in a minor way that adds a bit of colour to the day.
Deja vu is a soda burp of the mind. It provides a simple and straightforward means for anyone to experience their brain going wrong. It’s not necessarily unpleasant, just unusual. It exists to be savoured. This mental misfire is a gateway to the concept of our own fallibility. Deja vu is a flaring of the fire, showing us not just the shadows on the cave wall but the puppeteers themselves. We may not be able to process what we’ve seen, rendered inarticulate, our mouths flapping dumbly as our conscious mind reaches for words like “dream”, but for a moment we experience how fragile the whole puppet show is.
I personally experience a delightful grab-bag of low-level mental misfires - auditory hallucinations, minor delusions, intermittent face-blindness. As a teenager, I found this highly unsettling. But growing up means making peace with your oddities, and realising your own limitations and fallibility. Déjà vu provides the perfect vehicle for understanding this: no one’s brain works perfectly all the time. As an unassuming phenomenon, it doesn’t get enough credit for its load-bearing nature in daily experience. Having a name for something you have always thought or experienced can be freeing. There’s power in being able to say, “Ah, that’s a thing.” Like the liberation I felt the first time I encountered the word, “solipsism”. Now, I try to enjoy these mental misfires and simply delight in their soda-burp nature.[2] My brain handing me a quirky diversion from my day for you to enjoy as I please, like flapping my arm around when I’ve fallen asleep on it.
There are many examples in psychology where we can genuinely believe something to be true, only to later discover that we are incorrect. The Mandela effect, for example (one phenomenon that seems to actually replicate). What déjà vu provides that these other psychological effects do not is that it actually resolves itself through that sense of incorrectness. It is self-sufficient. We pause our own processing for a second and see the still frames that form the movie, only to press play again and carry on as before. You can now say, “huh, that was weird”, or you can recognise that the edifice on which your whole experience and understanding of the world is built is fragile and teetering.
A GATEWAY TO THE TRANSCENDENT
Many people seek out this sense of enlightenment and perspective through hallucinogenic drugs or the supernatural, but the realisation of our size and the scale of the world around us can be achieved through an often-overlooked pedestrian experience. Anyone who has experienced déjà vu, a brief and passing sense that something mundane may be of greater-than-expected importance, should be able to recognise some of the delusions experienced in schizophrenia.
Some may call this perspective pessimistic - the idea of déjà vu pulling down the curtain to reveal that it’s all a sham. Personally I find that delightful. Magic is only magic if you don’t know how it’s done. Once you know, it gets a different name, but the magic itself doesn’t go away. Which is more impressive, the handkerchief that appears from nowhere, or the months and years of practice to create the showmanship, the misdirection and the dexterity that culminate in the illusion?
As well as its role in understanding ourselves, déjà vu has provided a route to understanding the universe. As a phenomenon, it has always existed on the periphery of the uncanny. Emile Boirac, who gave the experience its name, was what we would call today a “parapsychologist” - publishing books on the psychic sciences and investigating mediums[3]. To many, this pedestrian experience is a weakening of the walls of reality. Rather than it being a glimpse into the workings of consciousness, it represents an opportunity to recognise the vastness of experience. Are we briefly experiencing the memories of our Other Selves, stepping from a parallel universe? Is this a moment of low-level clairvoyance? Are we briefly tapping into the Jungian collective unconscious? Incredible value and outsized performance from a simple brain hiccup.
I will leave it to the reader to decide how much merit they give to these more extraordinary experiences. Do these explanations have any more weight than the temporal medial lobe misfire? They are not necessarily mutually exclusive. (And as a disciple of Feyerabend, I would light-heartedly challenge anyone who asserts that one is more “objectively true” than the other).Why not keep the magic and the hallucinating meat?
Anyway, for the purposes of this review, it doesn’t matter. The point is that déjà vu provides us the option to engage with it on a level that we choose. We can see it as a passing mental misfire - pins and needles of the mind - or we can choose to let it fundamentally change our understanding of the nature of the universe. That is a sort of a revelation that normally requires illegal drugs.
IMPACT OF DEJA VU ON HUMANITY
Naturally, an experience of this has had a significant impact on art and culture. The most iconic cultural reference is the Matrix - the idea that we are living in a computer simulation, and that humanity has been through many futile illusory cycles of breaking free from the machine slavery. When Neo sees a black cat walk by twice, he’s told it’s a “glitch in the Matrix”—proof that his world is a computer simulation. Déjà vu becomes evidence that reality is fake. Given the fate of humanity in the movie, I’m not sure we can call that one optimistic.
The influence of déjà vu on humanity could be even more fundamental than explicit or disguised references in art. It is commonly accepted that fashion progresses through repeated cycles, (referenced here: https://slatestarcodex.com/2014/04/22/right-is-the-new-left/) There is nothing new under the sun: each generation reaches back several steps to appropriate previous cultural tropes.
Nostalgia, the opium of the elderly, is a powerful force, for good or for ill. Proust’s madeline provides an articulation of that warm glow of retreating into the familiar. Like déjà vu, nostalgia is often an unsought experience, but this time in reference to some that truly has been “already seen”. Or, if you prefer your involuntary recollections with a darker twist, there is the madeline’s evil twin, the ice-bucket shock of an intrusive thought from the past, post-traumatic reliving of a moment that could have gone slightly differently, with disastrous consequences. Even worse, perhaps the past is remembered with perfect clarity - that cruel thing you said once, breaking through your curated image of yourself with incontrovertible evidence that you are not who you wish yourself to be.
Some of our most affecting experiences as humans, the ones that can reach to the deepest core of who we are, relate to our memories. Do we experience déjà vu because we yearn for the past and our brain is trying too hard to oblige? Or perhaps the reason we are so affected by our recall is because of this error - our brain is used to searching our memories for recognition, and so we respond to this like a pastime?
Is that why it is so easy to be trapped on infinite scroll? We are searching for something we have almost seen before: we are presented the echo chamber we pretend not to want, because of our yearning for stimulus that feels familiar? In comedy, the technique is known as a call-back, a reference to a section from earlier. As a comedian, it’s brilliantly economical: you can get multiple laughs from the same joke. It is actually a force-multiplier - the subsequent laughs are bolstered by the warm notion of familiarity. The technique is so powerful that most comedians will end their set on a call-back, knowing that the audience’s delight will carry them off.
CONCLUSION
For a tiny day-to day absurdity, déjà vu punches well above its weight - the Singapore of mental mishaps. It gives us an opportunity to ask some of the biggest questions of our species: is there more than what we can see? Is anything we experience real? How do we know what we know? Available in a bitesize format without getting up from the couch, or taking anything stronger than a soda.
Some might find it unsettling that our brains go wrong so easily. I don’t. I think it’s like seeing the brushstrokes of reality. Knowing how its done only enhances the experience. YOu might not be able to call it magic when you know how the trick is done, but after that it becomes something even more impressive: craft, dedication, practice. The real marvel isn’t the trick itself, it’s the magician.
ENDNOTES:
[1] It also has several less interesting siblings, such as déjà entendu, but they do not interest me so I will leave them for you to explore at your leisure
[2] Except sleep paralysis. No thank you
[3] Media, surely?