That familiar unfamiliar feeling: What the opposite of déjà vu can tell us about cognitive delusions

As many people know, a bout of déjà vu can be a disorienting experience, like a momentary hiccup that distorts reality. Perhaps a friend says something and you suddenly feel like you’ve had this exact conversation before, or maybe you turn a corner on a street in a foreign city and you get the eerie sensation that this isn’t your first time there.

Some research suggests the part of the brain that recognizes the spatial layout of a place might be activated when it comes across similar physical landscapes, such that visiting a friend in an apartment complex that you’ve never been to before could trigger the sensation of déjà vu if its design shares many of the same features of another place. Yet déjà vu has puzzled scientists and non-scientists alike for centuries, and it’s still not entirely clear what causes it, leading to wilder theories like one that suggests déjà vu is a window into a parallel universe — much like a glitch in “The Matrix.”

If there is still mystery surrounding déjà vu, there are even more unknowns surrounding its lesser-known relative, jamais vu. (For the record, both are French loanwords meaning "already seen" and "never seen" respectively.) Described as the opposite of déjà vu, jamais vu occurs when something that is done repetitively or habitually suddenly feels foreign. If you’ve ever written a word over and over again and suddenly it no longer resembles anything in your lexicon, or if you’ve been practicing a musical instrument for hours and the sounds you’re producing no longer sound like a coherent song — that’s jamais vu.

Although the origins of jamais vu can be traced back to 1907, it’s now being researched with a renewed interest by a group of scientists in the U.K. Salon spoke with a member of the research team, Christopher Moulin, a professor of cognitive neuropsychology at the Université Grenoble Alpes (UGA) in France, about jamais vu and how learning more about it could provide insights into how the brain works and even perhaps help scientists better understand mental illness.

This conversation has been edited for clarity and length.

How did you introduce jamais vu in the laboratory setting and what did you find in your research when studying this?

It was all based on an experience I'd had as a child where I was given lines to write as punishment. I was writing the same thing repeatedly, and I noticed that writing the same thing repeatedly began to feel strange and it lost all its meaning. I always kept that in mind, and when I read about jamais vu, I [thought] this was definitely what was happening with this experience I had when I was a child. I thought we could run an experiment where we ask people to repeatedly write stuff and see if that does indeed lead people to these kinds of strange sensations. 

In our experiment, we used the word “the.” Our reasoning for using the word “the” was that we thought the more common a word was, the easier it would be to make it feel weird. Because the word “the” is so frequent and we've encountered it so much in our lives, we are quite sure that it's a real word and it does exist, therefore it should be easier to make it feel weird just because if you did it with a word that didn't really exist or a word that you don't see much in daily life, then presumably it can look weird just because it is an unfamiliar word.

Essentially, the take-home message was: It works, and a reliable amount of people said that they had the experience. Their experiences were feeling strange, like the word wasn't real, or not knowing if it was spelled right or the word kind of splitting down into different elements. So they had all these kinds of weird, jamais vu-type experiences. 

Can you explain a bit about the history of jamais vu? Who originally coined this term or studied it, and what did they find?

They never used the term “jamais vu,” so our unique selling point if we have one is to draw a parallel between this subjective experience of unreality and the strangeness of this kind of procedure for inducing these feelings.

The original experiments, which were done at the turn of the century, involved people staring at words or repeatedly saying words. It was all word-based and described at the time as “word alienation.” … They described it as a loss of associative power. At the time, the whole way of thinking about the human mind had to do with associations that were formed, like the low-level associations that you think of with Pavlov and pioneers of that type. The idea was, when you stared at stuff, you kind of broke down these associative links or over-stimulated these associative powers of the mind and that was what made you think that these words weren’t real anymore. 

What do we know about what is going on in the brain when this happens? What is the psychiatric or neurological element behind jamais vu?

We know extremely little in terms of concrete processes in the brain. With déjà vu, we know through work done with epilepsy patients which kinds of areas of the brain are involved and how the discharges move from one place to the other. We've also got experiments where we provoke déjà vu in the laboratory and we can see with neuroimaging what's going on in the brain. 

What's happening with déjà vu is a disconnection or a desynchronization between a part of the brain that is responsible for detecting familiarity and the other parts of the brain that are responsible for interpreting all those signals that it gets from familiarity. 

In comparison with déjà vu, we know very little [about jamais vu] … We don't have funded research to look at what happens in the brain whilst people are experiencing it, but that would be a very easy experiment to run because we can reliably produce these weird sensations and then we can see what's happening in the brain.

We do know that certain patient groups can experience déjà vu [more often], and the more we have déjà vu, the more we have jamais vu. 

How does this relate to conditions like obsessive-compulsive disorder (OCD)?  

One of the obvious parallels with jamais vu is the lack of meaning or the disruption in meaning that people get with repeated checking behaviors. So it seems that if staring at a word or repeating a word makes it meaningless, you can imagine that going to a door, for example, to keep checking whether it's locked or unlocked is going to at some point also become a meaningless activity. The more you do it, paradoxically, the less you will be sure that you've actually locked the door because just the act of going back and trying the handle will become repeated and meaningless. When you try and look back in your memory to whether you locked the door or not, instead of having one memory of the one time you went to the door and locked it, you've got to sift through all these many times that you went back and checked the door. 

Want more health and science stories in your inbox? Subscribe to Salon's weekly newsletter Lab Notes.

We haven't tried this and I don't feel particularly qualified to try it, but one thing to do in the context of cognitive behavioral therapy would be to give people jamais vu. … You can perhaps help break this vicious cycle that often exists in these checking behaviors, where people keep doing it because they need to check it in order to feel confident about things but in fact, the more you repeat something, the less confident you feel and there's this paradoxical effect. 

Some clinical psychologists, for instance, ask people to hyperventilate and show them what happens. If you hyperventilate, you start getting all the physiological symptoms that you get during a panic attack. They do that to make you aware of the kind of vicious cycle between starting a panic attack and things you start doing including hyperventilation, which makes you feel more anxious, which makes you hyperventilate more, which makes you feel worse. It kind of changes the relationship between breathing and how they're feeling physiologically.

These cognitive behavioral therapies and metacognitive approaches to understanding behaviors often do that sort of thing. They're about symptom education and getting people to experience the same kind of feelings or the same kind of traumas differently. That’s what you could do with jamais vu. I think you can make somebody feel this kind of strange feeling of unreality in order to help people explain it and maybe control it a bit better.

Are there other ways we could potentially think about how understanding jamais vu could help further our understanding of other psychiatric or mental health conditions?

One we often talk about is delusions like Capgras [syndrome], which is a delusion that occurs with several different kinds of pathologies, including schizophrenia, and I've also seen it in people with Alzheimer's disease. That's where somebody who is very familiar, often like a member of the family, appears as if they're an impostor. So the person says, “I know that looks like my wife, but it's not my wife. It's a robot or it's an alien or it's somebody pretending to be my wife.” 

The cognitive neuropsychiatry of those cases is something which is exactly like jamais vu. But obviously, it's like jamais vu, plus, plus, plus. So with Capgras, you have this underlying knowledge that it looks like your partner, but there's a disruption in your subjective feeling of familiarity. In jamais vu, we correct that. We've got this control over that and it feels weird for a millisecond or second or maybe even a couple of seconds, but then we correct it. There's something that says “No. It's not possible. That's a weird feeling.” And the weird feeling is resolved. 

We think what happens with Capgras is that you get that secondary attribution, which is exactly like the jamais vu, but it runs wild. It's not checked, there's nothing to control it. There's nothing to stop it, so instead of rejecting that weird feeling and this kind of conflict between a feeling — where you know that person looks right, but it's somehow weird — you just start justifying why it feels weird and that's what creates the delusion. 

I'm not saying at all that [jamais vu] is a delusion … But one way to think of Capgras is to think of it in some way like a chronic failure of this kind of familiarity system. Certainly, we're not alone in saying that — the idea with Capgras has been around for at least 20 years, I think. But our novel contribution is to say, perhaps jamais vu is very much comparable to those things, and at the heart of all those kinds of delusional states is something that is a bit like the conflict and confusion of the jamais vu experience.

From an evolutionary sense, this could be a sort of reality check. Can you elaborate on why this is happening in that sense?

When I did my PhD, I was interested in metacognition in Alzheimer's disease. Metacognition is your higher-order thought processes which you use to look at what's happening in your cognitive system. So it's thinking about thinking. In general, it's like the awareness you have, how you're thinking, what you're thinking, how you can better memorize a list of words or the feeling of having a word on the tip of the tongue — that's all a metacognitive feeling. That's a feeling that tells you, “I know this word, yet I can't produce the word.”

You've got this very pure sensation that you know something and that feeling that you know something is metacognitive. The idea with déjà vu and jamais vu and having a word on the tip of your tongue is that they are all connected. In fact, they are metacognitive and [our hypothesis is], they exist to make sure your thoughts don't run away or that you don't start thinking absurd and illogical things based on a tiny error. 

In déjà vu, the error is that you find something familiar, and then there's a bit of information that comes by and says, [that’s not possible]. We imagine for jamais vu, it’s the same thing but maybe there's just a little miniature synchronization of brainwaves or something, a physiological [element] in the brain, which makes you think “This looks strange, or it's not familiar.” Then there's something that quickly comes afterward and says ["That’s not possible."] 

The jamais vu is the detection of that conflict just like déjà vu is the detection of conflict. It's really a higher-order control process, which exists to study what you're thinking and to stop thought processes that would not be beneficial, like repeatedly doing the same thing and getting stuck in a loop or maybe always looking at somebody in the same way. It’s a little reflection, like a safety valve. 

Are there any plans for future research in terms of jamais vu?

There's some pretty basic research to be done in terms of neuroimaging, even just using electroencephalogram (EEG) technology to see which part of the brain is synchronized or desynchronized at the time in which people feel jamais vu. Because it's so reliable to produce it, I think there's some really decent neuroscientific research to be done.

If we can understand these things, and how they work in the brain, I think on the way we'll unlock lots of things that are important to understanding delusions, conscious control of the mind and conditions like OCD and schizophrenia and all kinds of things like that.