Never seen it before

Ever heard of the opposite of déjà vu -- jamais vu?

This may sound like it's the setup for some sort of abstruse bilingual joke, but it's not.  Déjà vu ("already seen" in French) is, as you undoubtedly know, the sensation that something you're experiencing has happened exactly that way before even though you're certain it can't have (a phenomenon, by the way, which is still yet to be fully explained, although there was a suggestive study out of Colorado State University five years ago that gave us some interesting clues about it).  Jamais vu ("never seen") is indeed the opposite; the eerie sense that something completely familiar is unfamiliar, uncertain, or simply incorrect.

One of the most common forms of jamais vu is an experience a lot of us have had; looking at a word and convincing ourselves that it's misspelled.  It can happen even with simple and ridiculously common words.  I remember being a teenager and working on a school assignment, and staring at the word "were" for what seemed like ages because suddenly it looked wrong.  The same thing can happen with music -- skilled musicians can reach a point in a piece they've practiced over and over, and suddenly it feels unfamiliar.  Less common, but even more unsettling, are reports where people look at faces of family and friends, and have the overwhelming sensation that they have never seen them before.

The emphasis here is on "looks" and "feels" and "sensation."  This seems not to be a cognitive issue but a sensory-emotional one; when I've had jamais vu over the spellings or definitions of words, and I look the word in question up, almost always what I'd been writing turned out to be correct even though it felt wrong.  The people who had the sense that their loved ones' faces were somehow unfamiliar still knew their names and relationships, so their cognitive understanding of who those people were was undiminished; it was the "gut feeling" that was all wrong.

[Image courtesy of creator © Michel Royon / Wikimedia Commons Brain memory, CC0 1.0]

The reason the subject comes up is that a team led by Chris J. A. Moulin of the Université Grenoble Alpes has done a preliminary look into the strange phenomenon of jamais vu, and their results were the subject of a paper in the journal Memory.  Their research started with a simple question: can jamais vu be induced?  The answer was yes, and by a simple protocol -- repeat something often enough, and it starts to look strange.

The researchers took familiar words like "door" and less familiar ones like "sward," and asked volunteers to write them repeatedly until they wanted to stop.  They were told they could stop for whatever reason they wanted -- tired hand, bored, feeling peculiar, whatever -- but to be aware of why they stopped.  It turned out that by far the most common reason for stopping was "feeling strange," which was cited as the cause by seventy percent of the volunteers.  The effect was more pronounced with common words than uncommon ones, as if we kind of expect to see uncommon words as odd, so it doesn't strike us as off.

It even happened with the most common word in the English language -- "the."  It only took 27 repetitions, on average, for people to halt.  One volunteer said, "[Words] lose their meaning the more you look at them."  Another, even more interestingly, said, "It doesn't seem right.  It almost looks like it's not really a word, but someone's tricked me into thinking it is."

The researchers believe that jamais vu isn't just some kind of psychological fluke.  It may serve a purpose in jolting us when our cognitive processes are going onto autopilot -- as they can, when we're asked to do a repetitive task too many times.  That feeling of strangeness brings us back to a state of high alertness, where we're paying attention to what we're doing, even if the downside is that it makes us think we've made mistakes when we haven't.

"Jamais vu is a signal to you that something has become too automatic, too fluent, too repetitive," the authors write.  "It helps us 'snap out' of our current processing, and the feeling of unreality is in fact a reality check.  It makes sense that this has to happen.  Our cognitive systems must stay flexible, allowing us to direct our attention to wherever is needed rather than getting lost in repetitive tasks for too long."

So a sense of peculiarity when we're doing ordinary stuff might actually have an adaptive benefit.  Good to know, because it's really unsettling when it happens.

But for what it's worth, I still don't think "were" should be spelled like that.

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Been there, done that

One of the strangest and most ubiquitous sensations is déjà vu, that bizarre sense that you're experiencing something that's happened before.  The name is French and means "already seen," but for some of us -- myself included -- the experience is almost always auditory.  It doesn't happen often, but when it does, it's absolutely convincing.  The last really striking experience I had with déjà vu occurred about three years ago, when I was talking to the seventh-grade life science teacher about some interesting concept in genetics, and I was suddenly certain that I'd had this conversation before.

I recognized it -- the exchange, where we were standing, what we were discussing, even what particular words were spoken.  It was uncanny -- and unnerving.  My perplexity must have shown in my face, because my colleague said, "What's wrong?"  I explained to her what was going on, and asked if we'd discussed this before.

She shrugged.  "I don't think so.  At least not that I recall."

But her reassurance did nothing to change the feeling.  After the discussion was over, I was still sure -- despite my rational knowledge to the contrary -- that she and I had had that exact conversation before.

[Image licensed under the Creative Commons hagerman, Déjà Vu (Six Flags Over Georgia) 01, CC BY 2.0]

I've heard a few explanations of déjà vu, none of them convincing.  Certainly, the paranormal ones don't seem to me to hold any water -- that it's evidence of reincarnation, or precognition, or astral transport (the subject having visited the place in spectral form, apparently), or telepathy (you're picking up the memories of someone else).  One at least minimally plausible one is that the information our brain is receiving from the senses is out of sync with our processing, so by the time the input is integrated and interpreted the sensory parts register it as already having happened.  But even this one doesn't make a lot of sense, given what I know of neuroscience; the time for sensory processing and interpretation in a normally-functioning brain is on the scale of milliseconds, so it seems highly unlikely to me that there could be a significant enough delay in one branch of the system to account for some kind of out-of-sync reception of the signal.

Last week, though, a study from Colorado State University was published in Psychonomic Bulletin & Review that is the first explanation of the phenomenon I've heard that really makes sense.  In "A Postdictive Bias Associated With Déjà Vu," Anne M. Cleary, Andrew M. Huebert, Katherine L. McNeely-White, and Kimberly S. Spahr show that in the middle of an episode of déjà vu, we're actually lousy at predicting what's going to happen next (which surely should occur if we really did somehow live through this moment before), but that the familiarity of some feature of the event triggers a response in the brain after the fact that gives rise to the feeling we knew what was going to happen before it did.

The authors write:

Recent research links reports of déjà vu – the feeling of having experienced something before despite knowing otherwise – with an illusory feeling of prediction.  In the present study, a new finding is presented in which reports of déjà vu are associated not only with a predictive bias, but also with a postdictive bias, whereby people are more likely to feel that an event unfolded as expected after the event prompted déjà vu than after it did not.  During a virtual tour, feelings of predicting the next turn were more likely during reported déjà vu, as in prior research.  Then, after actually seeing the turn, participants exhibited a postdictive bias toward feeling that the scene unfolded as expected following déjà vu reports.  This postdictive bias following déjà vu reports was associated with higher perceived scene familiarity intensity.  A potential reason for this association may be that high familiarity intensity as an event outcome unfolds falsely signals confirmatory evidence of having sensed all along how it would unfold. 

"If the entire scene feels intensely familiar as it unfolds, that might trick our brains into thinking we got it right after all," said study lead author Anne Cleary, in an interview with Science Daily. "Because it felt so familiar as you were going through it, it felt like you knew all along how it was going to go, even if that could not have been the case."

So unfortunately for those who like a supernatural explanation for things, it looks like déjà vu might well be another case of our brain being presented with conflicting explanations for something, and putting them together the best way it can (which in this case, is wrong).  In that sense, it's a little like those optical illusions showing forks with three prongs at one end and two at the other, or circular staircases that keep rising but end up where they started.  Your brain tries to shoehorn what it's getting into some kind of sense, and ends up with an incomplete, or outright erroneous, picture of things.

What I find funny is that even though this explanation makes good sense to me, when I experience déjà vu I am still left with the completely persuasive feeling that something uncanny has happened.  All of which once again illustrates that even us skeptics aren't as purely rational as we'd like to be -- or as we'd like everyone to think we are.

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Last week's Skeptophilia book recommendation was a fun book about math; this week's is a fun book about science.

In The Canon, New York Times and Pulitzer Prize-winning writer Natalie Angier takes on a huge problem in the United States (and, I suspect, elsewhere), and does it with her signature clarity and sparkling humor: science illiteracy.

Angier worked with scientists from a variety of different fields -- physics, geology, biology, chemistry, meteorology/climatology, and others -- to come up with a compendium of what informed people should, at minimum, know about science.  In each of the sections of her book she looks at the basics of a different field, and explains concepts using analogies and examples that will have you smiling -- and understanding.

This is one of those books that should be required reading in every high school science curriculum.  As Angier points out, part of the reason we're in the environmental mess we currently face is because people either didn't know enough science to make smart decisions, or else knew it and set it aside for political and financial short-term expediency.  Whatever the cause, though, she's right that only education can cure it, and if that's going to succeed we need to counter the rote, dull, vocabulary-intense way science is usually taught in public schools.  We need to recapture the excitement of science -- that understanding stuff is fun.  

Angier's book takes a long stride in that direction.  I recommend it to everyone, layperson and science geek alike.  It's a whirlwind that will leave you laughing, and also marveling at just how cool the universe is.

I'm sure I already told you about this...

One of the most peculiar sensations in the world is déjà vu.  I typically have the auditory version -- I am completely convinced that I have had this conversation before.  Others tend to have more visual déjà vu, having a certainty that they've been in a place where they know they've never been.

I'd heard a number of explanations of the phenomenon -- that it was memory being triggered subliminally by another sense, or that it came from the fact that our sensory processing and cognitive processing were running at different speeds, so the by the time everything was integrated it created a false memory of an experience that had already occurred.  Neither of those has ever sounded all that convincing to me.

[image courtesy of the Wikimedia Commons]

Nor, I must add, did all of the woo-woo explanations, such as the idea that déjà vu was precognition, or a visitation by a ghost, or the recollection of an experience from a previous life.

Now, cognitive neuroscientists Josephine Urquhart and Akira O'Connor of the University of St. Andrews (Scotland) have devised an experiment that gives us at least a window on what might be going on -- by creating a situation where déjà vu can be induced.

The setup is simple and elegant.  You give your test subjects a list of words to memorize, and include several that have to do with sleeping -- bed, blankets, dreams, pillow.  "Sleep" itself is not included.  After studying the list, you ask the subjects if there were any words on the list beginning with the letter "s" (there weren't).  Afterwards, you ask them if the word "sleep" was on the list.

They know it couldn't have been, because they all answered in the negative regarding there being words beginning with "s" -- but when asked the question, most of the test subjects experienced an eerie sense of déjà vu, that the word "sleep" actually was on the list -- or, perhaps, on another similar list they'd seen before, somewhere else.  Urquhart and O'Connor write:

Déjà vu is a nebulous memory experience defined by a clash between evaluations of familiarity and novelty for the same stimulus.  We sought to generate it in the laboratory by pairing a DRM recognition task, which generates erroneous familiarity for critical words, with a monitoring task by which participants realise that some of these erroneously familiar words are in fact novel...  The key omission in [prior] déjà vu generation procedures... is the provision of information allowing the participant to make an evaluation of unfamiliarity or novelty to clash with the experimentally-generated familiarity.  In these procedures, there was no objective standard by which participants could verify that the stimuli provoking familiarity had in fact not previously been encountered.

Interestingly, when the subjects were being tested, they were simultaneously being monitored by an fMRI scanner -- and when the feelings of déjà vu were the most intense, the areas in the brain involved in memory (such as the hippocampus) were not very active.  Instead, the frontal cortex -- the part of the cerebrum responsible for decision-making -- was lighting up like mad.

O'Connor and Urquhart believe that the explanation for this is that déjà vu comes from our memory's error-checking procedure.  When we are forming memories, the frontal cortex is doing a continual spot-check to make sure that what is being placed into memory is accurate.  When an error is noted, it's brought to our attention.  Most of the time, the error is something that can be resolved quickly -- with a conclusion of "okay, that's not the way it happened."  But when the memory being analyzed is close in content to something else, especially something that the conscious brain knows can't have occurred, it generates a conflict that is what results in the sensation of déjà vu.

This is still a tentative finding -- there is a great deal we don't understand about memory and sensory processing, so concluding that the phenomenon of déjà vu is explained is probably premature.  But to my thinking, this is a hell of a lot better explanation than anything else I've heard.  O'Connor and Urquhart are going to continue trying to explore the phenomenon.  As a mysterious sensation that is nearly universal to all humans, it certainly begs explaining.  But look for more studies coming down the pike.  And don't forget: you heard it here first.

Stop me if I've already told you about this

One of the most ubiquitous, but mysterious, phenomena in neuroscience is déjà vu.

We all get it from time to time -- the uncanny sense that what we're experiencing has happened before.  For some people, it's usually visual in nature; that they've seen that room, seen those people, know that particular part of the city, despite a certainty that such foreknowledge is impossible.  For me, it's most often auditory.  Just a few weeks ago, I was talking with a colleague about the discovery of some new fossils from the early Cambrian era (the age of the "Cambrian Explosion," the sudden diversification of animal life into multitudes of forms), and I had the unsettling feeling that I'd had that conversation with her already.

"Didn't we already talk about this?" I asked her.

She assured me that we hadn't.

There are a multitude of unsupported woo-woo explanations for the phenomenon -- a premonition, a memory from a previous life, even a momentary side-slip into an alternate timeline (à la the "Many Worlds" interpretation of quantum mechanics).  Predictably, I don't think much of these, mostly because they have little testability and even less evidence in their favor.  So they really don't count as scientific explanations.

The problem is, science has come up pretty much empty-handed itself.  Déjà vu is so unpredictable, so quick to strike and so quickly over, that it's not like you can stick someone in an fMRI machine and just sit around and wait until it happens.  It's known that there are some medications that can increase the frequency of déjà vu -- a combination of phenylpropanolamine and amantidine, used to relieve flu symptoms, has been documented to trigger intense and recurrent déjà vu in some people.

No one is really certain why.

[image courtesy of the National Institute for Aging and the Wikimedia Commons]

Other explanations include a subconsciously-recalled memory being stimulated by a different, but similar, stimulus, creating a sensation of the event having already been experienced; and a dreamed scene producing what amounts to an "invented memory" that could be similarly triggered.

Neither of these, to me, explains the commonness, nor the power, of these experiences.  I know that memory is unreliable and plastic, but even so, déjà vu is so striking that it deserves a better explanation.

Recently, however, a study by Christine Wells et al. has shed some interesting light on this phenomenon.  Wells and her team found that a patient with severe anxiety disorder was experiencing profound and repeated déjà vu, and the researchers speculate that this is no coincidence:

Whereas previous cases with déjà vu due to MCI [mild cognitive impairment] and dementia have largely been anosognosic [not acknowledged as clinically relevant by the patient], our case is aware of the abnormal familiarity in his memory, and is in fact greatly distressed by it.  This suggests two dimensions along which déjà vu experiences can vary: awareness and distress.  In this psychogenic case, our patient is similarly aware of the unreality of his experiences and they are constantly accompanied or caused by pathological levels of anxiety...  In relation to our case, distress caused by the déjà vu experience may itself lead to increased levels of déjà vu: similar feedback loops in positive symptoms are reported in other anxiety states (e.g. panic attacks). 

It is plausible on neurobiological grounds that anxiety might lead to the generation of déjà vu.  The hippocampal formation, a structure of central importance in declarative memory and the ability to engage in recollection, is also implicated in anxiety as part of the septo-hippocampal system.  Although this report does not prove a link between anxiety and déjà vu, it does further support the suggestion that this area is worthy of further investigation.

It certainly is.  You have to wonder if even people who do not suffer from a clinical anxiety disorder might experience déjà vu more commonly when they're distressed or anxious about something.  Stress does affect health -- there's no real doubt about that -- could it also be responsible for fleeting pseudo-memories?

All of which is fascinating and suggestive.  It's further evidence of what a friend of mine once said -- she's a retired professor of human genetics at Cornell, and she said if she were going into research now, she'd go into neurology instead of genetics.  "Right now, in terms of our understanding of the brain, we're where our understanding of genes was in the early 20th century.  We know a little about what's going on, mostly descriptively, but little real comprehension of how it's all happening.  The 20th century was the century of the gene; the 21st will be the century of the brain."

But I've told you that quote before, haven't I?  I'm sure I've used that quote before.