Remembrance of things past

"The human brain is rife with all sorts of ways of getting it wrong."

This quote is from a talk by eminent astrophysicist Neil deGrasse Tyson, and is just about spot on.  Oh, sure, our brains work well enough, most of the time; but how many times have you heard people say things like "I remember that like it was yesterday!" or "Of course it happened that way, I saw it with my own eyes"?

Anyone who knows something about neuroscience should immediately turn their skepto-sensors up to 11 as soon as they hear either of those phrases.

fMRI scan of a human brain during working memory tasks [Image is in the Public Domain courtesy of the Walter Reed National Military Medical Center]

Our memories and sensory-perceptual systems are selective, inaccurate, heavily dependent on what we're doing at the time, and affected by whether we're tired or distracted or overworked or (even mildly) inebriated.  Sure, what you remember might have happened that way, but -- well, let's just say it's not as much of a given as we'd like to think.  An experiment back in 2005 out of the University of Portsmouth looked memories of the Tavistock Square (London) bus bombing, and found that a full forty percent of the people questioned had "memories" of the event that were demonstrably false -- including a number of people who said they recalled details from CCTV footage of the explosion, down to what people were wearing, who showed up to help the injured, when police arrived, and so on.

Oddly enough, there is no CCTV footage of the explosion.  It doesn't exist and has never existed.

Funny thing that eyewitness testimony is considered some of the most reliable evidence in courts of law, isn't it?

There are a number of ways our brains can steer us wrong, and the worst part of it all is that they leave us simultaneously convinced that we're remembering things with cut-crystal clarity.  Here are a few interesting memory glitches that commonly occur in otherwise mentally healthy people, that you might not have heard of:

• Cryptomnesia.  Cryptomnesia occurs when something from the past recurs in your brain, or arises in your external environment, and you're unaware that you've already experienced it.  This has resulted in several probably unjustified accusations of plagiarism; the author in question undoubtedly saw the text they were accused of plagiarizing some time earlier, but honestly didn't remember they'd read it and thought that what they'd come up with was entirely original.  It can also result in some funnier situations -- while the members of Aerosmith were taking a break from recording their album Done With Mirrors, they had a radio going, and the song "You See Me Crying" came on.  Steven Tyler said he thought that was a pretty cool song, and maybe they should record a cover of it.  Joe Perry turned to him in incredulity and said, "That's us, you fuckhead."

• Semantic satiation.  This is when a word you know suddenly looks unfamiliar to you, often because you've seen it repeatedly over a fairly short time.  Psychologist Chris Moulin of Leeds University did an experiment where he had test subjects write the word door over and over, and found that after a minute of this 68% of the subjects began to feel distinctly uneasy, with a number of them saying they were doubting that "door" was a real word.  I remember being in high school writing an exam in an English class, and staring at the word were for some time because I was convinced that it was spelled wrong (but couldn't, of course, remember how it was "actually" spelled).

• Confabulation.  This is the recollection of events that never happened -- along with a certainty that you're remembering correctly.  (The people who claimed false memories of the Tavistock Square bombing were suffering from confabulation.)  The problem with this is twofold; the more often you think about the false memory or tell your friends and family about it, the more sure you are of it; and often, even when presented with concrete evidence that you're recalling incorrectly, somehow you still can't quite believe it.  A friend of mine tells the story of trying to help her teenage son find his car keys, and that she was absolutely certain that she'd seen them that day lying on a blue surface -- a chair, tablecloth, book, she wasn't sure which, but it was definitely blue.  They turned the house upside down, looking at every blue object they could find, and no luck.  Finally he decided to walk down to the bus stop and take the bus instead, and went to the garage to get his stuff out of the car -- and the keys were hanging from the ignition, where he'd left them the previous evening.  "Even after telling me this," my friend said, "I couldn't accept it.  I'd seen those keys sitting on a blue surface earlier that day, and remembered it as clearly as if they were in front of my face."

• Declinism.  This is the tendency to remember the past as more positive than it actually was, and is responsible both for the "kids these days!" thing and "Make America Great Again."  There's a strong tendency for us to recall our own past as rosy and pleasant as compared to the shitshow we're currently immersed in, irrespective of the fact that violence, bigotry, crime, and general human ugliness are hardly new inventions.  (A darker aspect of this is that some of us -- including a great many MAGA types -- are actively longing to return to the time when straight White Christian men were in charge of everything; whether this is itself a mental aberration I'll leave you to decide.)  A more benign example is what I've noticed about travel -- that after you're home, the bad memories of discomfort and inconveniences and delays and questionable food fade quickly, leaving behind only the happy feeling of how much you enjoyed the experience.

• The illusion of explanatory depth.  This is a dangerous one; it's the certainty that you understand deeply how something works, when in reality you don't.  This effect was first noted back in 2002 by psychologists Leonid Rozenblit and Frank Keil, who took test subjects and asked them to rank from zero to ten their understanding of how common devices worked, including zippers, bicycles, electric motors, toasters, and microwave ovens, and found that hardly anyone gave themselves a score lower than five on anything.  Interestingly, the effect vanished when Rozenblit and Keil asked the volunteers actually to explain how the devices worked; after trying to describe in writing how a zipper works, for example, most of test subjects sheepishly realized they actually had no idea.  This suggests an interesting strategy for dealing with self-styled experts on topics like climate change -- don't argue, ask questions, and let them demonstrate their ignorance on their own.

• Presque vu.  Better known as the "tip-of-the-tongue" phenomenon -- the French name means "almost seen" -- this is when you know you know something, but simply can't recall it.  It's usually accompanied by a highly frustrating sense that it's right there, just beyond reach.  Back in the days before The Google, I spent an annoyingly long time trying to recall the name of the Third Musketeer (Athos, Porthos, and... who???).  I knew the memory was in there somewhere, but I couldn't access it.  It was only after I gave up and said "to hell with it" that -- seemingly out of nowhere -- the answer (Aramis) popped into my head.  Interestingly, neuroscientists are still baffled as to why this happens, and why turning your attention to something else often makes the memory reappear.

So be a little careful about how vehemently you argue with someone over whether your recollection of the past or theirs is correct.  Your version might be right, or theirs -- or it could easily be that both of you are remembering things incompletely or incorrectly.  I'll end with a further quote from Neil deGrasse Tyson: "We tend to have great confidence in our own brains, when in fact we should not.  It's not that eyewitness testimony by experts or people in uniform is better than that of the rest of us; it's all bad....  It's why we scientists put great faith in our instruments.  They don't care if they've had their morning coffee, or whether they got into an argument with their spouse -- they get it right every time."

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Invention of things past

On July 7, 2005, an Islamic suicide bomber detonated an explosive device on a double-decker bus in Tavistock Square, London, killing thirteen people and injuring dozens of others.  It was part of a coordinated series of attacks that day that took 52 lives.

Understandably, investigators put a tremendous amount of effort into trying to determine what exactly had happened on that horrible day.  They questioned eyewitnesses, and of course the case was all over the news for weeks.  Three years later, a man named James Ost, of the University of Portsmouth, became interesting in finding out what impact the event had made on people who lived nearby at the time, and began to interview locals.

A common theme was how traumatizing it had been to watch the CCTV footage of the actual Tavistock explosion.  Four out of ten people Ost interviewed had details seared into their brains -- hearing the screams, seeing the debris flying in all directions.  One man said he remembered actually seeing someone -- he wasn't sure if it was a passenger or the bomber himself -- blown to bits.  More than one said they had felt reluctant to watch it at the time, and afterwards regretted having done so.

All of which is fascinating -- because there is no CCTV footage of the explosion.  In fact, no video record of the bombing, of any kind, exists.

Ost's study was not the first to look at the phenomenon of false or invented memory, but it's justifiably one of the most famous.  A couple of things that are remarkable about this study are the Ost didn't give much of a prompt to the test subjects about video footage; he simply asked them to recall as much as they could about what they'd seen of the bombing, and the subjects came up with the rest on their own.  Second, the memories had astonishing detail, down to the color of clothing some of the people in the imagined video were wearing.  And third -- most disturbingly -- was the power of the false memory.  Several test subjects, when told there was no footage of the attack, simply refused to believe it.

"But I remember it," was the common refrain.

Our memories are incomplete and inaccurate, filled with lacunae (the psychological term for gaps in recall), and laced through with seemingly sharp details of events that never actually happened.  Those details can come from a variety of sources -- what we were told happened, what we imagine happened, what happened to someone else that we later misremembered as happening to us, and outright falsehoods.  Oh, sure, some of what we remember is accurate; but how do you know which part that is, when the false and inaccurate memories seem just as vivid, just as real?

[Image licensed under the Creative Commons © Michel Royon / Wikimedia Commons, Brain memory, CC0 1.0]

The scariest part is how quickly those errors start to form.  In the last fifteen seconds, I took a sip of my morning coffee, looked out of the window at a goldfinch on my bird feeder, noticed that my dog had gotten up because I could hear him eating his breakfast in the next room.  How in the hell could I be remembering any of that incorrectly, given that it all happened under a minute ago?

Well, a paper that appeared last week in PLOS-One, about a study done at the University of Amsterdam, showed that inaccuracies in our memories increase by 150% in the time between a half-second and three seconds after the event occurs.

The study was simple and elegant.  Test subjects were shown words with highlighted letters, and asked to recall two things; which letter was highlighted, and whether the highlighted letter was shown in its normal orientation or else reversed right-to-left.  Most people were pretty good at recalling what the highlighted letter was, but because seeing mirror-image letters is not something we expect, recognizing and recalling that took more effort.

And if you wait three seconds, the error rate for remembering whether the letter was reversed climbs from twenty to thirty percent.  Evidently, our memory very quickly falls back on "recalling" what it thinks we should have seen, and not what we actually did see.

It's a profoundly unsettling finding.  It's almost like our existence is this moving window of reality, and as it slips by, the images it leaves behind begin to degrade almost immediately.  "I know it happened that way, I remember it clearly" is, honestly, an absurd statement.  None of us remembers the past with any kind of completeness or clarity, however sure we feel about it.  Unless you have a video of the events in question, I'd hesitate to trumpet your own certainty too loudly.

And, of course, it also means you have to check to see if the video itself actually exists.

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The mental delete key

About ten years ago, some students in my AP Biology class decided to do an experiment on false memory as their final project.

The setup was simple and elegant.  One of the students sat behind a small card table on which there were two dozen objects of various types and sizes, initially covered by a cloth.  The test subject came in, sat down, and was told (s)he would be given a memory test at the end of three minutes' time to study the objects on the table.  The cloth was removed, the timer started.

At a minute and a half in, the other student running the study -- who until then had been offstage -- came in, picked up one of the objects, and walked off with it.  Naturally enough, the test subjects focused on which object she'd picked up.

When the three minutes were up, the test subject was read aloud a series of twelve questions about the experience.  The answers to only three of them mattered -- the first one and the last two:

• Question 1: What object did the girl in the blue shirt remove from the table?
• Question 11: The girl who came in and removed an object -- what color was her shirt?
• Question 12: How do you know what color her shirt was?

You've probably already guessed that her shirt wasn't blue; in fact, it was brilliant red.  But 95% of the fairly sizable number of test subjects answered "blue."  Only two test subjects said "red;" several of them said "I don't remember."

But where it got seriously interesting was how the subjects who said "blue" answered question #12.  Because the vast majority of them said, "I remember seeing it."  Once again, there were only a couple of outliers who said "Because you told me it was blue in question #1," and one or two who said, "I'm not sure."  The remainder were convinced they remembered seeing it.  When informed that the other member of the scientific team had been wearing a red shirt, several people flat-out didn't believe it and asked that she come back and prove it to them.  One of them even accused her of having changed her shirt!

This has always been one of my favorite examples of how plastic and unreliable human memory is.  "I know it happened that way, I remember it" is remarkably thin ice.  My students' clever experiment is innocuous enough, but think of the role false memories could play in a court of law -- where someone's freedom, perhaps their life, depends on the people on the witness stand remembering what actually happened.

So that's kind of sobering.  But a study this week which appeared in Proceedings of the National Academy of Sciences gives us some encouraging news; false memories are easier to eradicate than real memories -- indicating they may be stored differently in the brain, and don't get the same weight as memories of events that we really witnessed.

[Image "Brain/Memory" licensed under the Creative Commons © Michel Royon / Wikimedia Commons]

In "Rich False Memories of Autobiographical Events Can Be Reversed," Aileen Oeberst (University of Hagen), Merle Madita Wachendörfer (Leibniz-Institut für Wissensmedien), Roland Imhoff (Johannes Gutenberg Universität Mainz), and Hartmut Blank (University of Portsmouth) show us a simple protocol by which people can be induced to purge their brains of false or implanted memories.  They took a test group of 52 individuals whose parents had also agreed to participate.  Without being told what exactly was going on, the test subjects were given a period during which their parents recalled with them a series of childhood memories -- but in each case, two of the "memories" were false and the rest were not.  (Examples of false memories implanted were incidents like running away from home, getting lost, or being in a car accident -- more serious and emotion-laden than what shirt someone was wearing!)

As with previous experiments, the test subjects afterward were unable to tell apart the real memories from the false ones; both seemed to exist in their minds with equal intensity.  Then the researchers tried two approaches to eradicate the false memories: (1) alerting the test subjects to the possibility that their memories were false, and were due to other sources, such as family narratives; and (2) asking test subjects to describe how they know their memories were true (a little like the "How did you know her shirt was blue?" question my students asked).

Both of them worked, and more interesting still, memories of real events were unaffected when the researchers tried the same strategy on them.  Put differently, asking people to slow down and consider their brain's fallibility, and the sources of what they think they recall, had the effect of deleting false memories but not real ones.

Even more interesting was how persistent the effect was.  A one-year followup on the test subjects found that the implanted memories were virtually all gone -- asked whether an unreal event had happened in their childhood, almost all the volunteers rejected it.

"By raising participants' awareness of the possibility of false memories, urging them to critically reflect on their recollections and strengthening their trust in their own perspective, we were able to significantly reduce their false memories. Moreover, and importantly, this did not affect their ability to remember true events," said study senior author Hartmut Blank, in an interview with Science Daily.  "We designed our techniques so that they can principally be applied in real-world situations.  By empowering people to stay closer to their own truth, rather than rely on other sources, we showed we could help them realize what might be false or misremembered -- something that could be very beneficial in forensic settings."

Very encouraging indeed.  Nice to hear that our brains aren't quite as easily duped as we'd thought.  It does make me wonder, though, how these more-easily-eradicated false memories are encoded in the brain.  Is there a neurological reason why the false memories are susceptible to a mental delete key, and the real ones aren't?  What I'd love to see is a comparison of fMRI results of people recalling real and implanted memories.

Maybe a direction for a subsequent experiment.  But at least now we have some hope of sifting out the wheat from the chaff in our brains -- and remembering more accurately what really happened, even if it's just what color shirt someone was wearing.

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If, like me, you love birds, I have a book for you.

It's about a bird I'd never heard of, which makes it even cooler.  Turns out that Charles Darwin, on his epic voyage around the world on the HMS Beagle, came across a species of predatory bird -- the Striated Caracara -- in the remote Falkland Islands, off the coast of Argentina.  They had some fascinating qualities; Darwin said they were "tame and inquisitive... quarrelsome and passionate," and so curious about the odd interlopers who'd showed up in their cold, windswept habitat that they kept stealing things from the ship and generally making fascinating nuisances of themselves.

In A Most Remarkable Creature: The Hidden Life and Epic Journey of the World's Smartest Birds of Prey, by Jonathan Meiberg, we find out not only about Darwin's observations of them, but observations by British naturalist William Henry Hudson, who brought some caracaras back with him to England.  His inquiries into the birds' behavior showed that they were capable of stupendous feats of problem solving, putting them up there with crows and parrots in contention for the title of World's Most Intelligent Bird.

This book is thoroughly entertaining, and in its pages we're brought through remote areas in South America that most of us will never get to visit.  Along the way we learn about some fascinating creatures that will make you reconsider ever using the epithet of "birdbrain" again.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Remembrance of things past

Sometimes science uncovers things that are profoundly unsettling.  The problem is, as Neil deGrasse Tyson pointed out, "The good thing about science is that it's true whether or not you believe it."

Believing it, though, can run counter to our own intuition.  Consider, for example, the work of Julia Shaw, psychologist and lecturer at London South Bank University, which indicates that much of what we think we remember is simply wrong.

Shaw is a specialist in "false memory," our brain's ability to craft completely convincing memories of events that never happened.  And they're not minor and uncommon glitches, but pervasive and unavoidable.  "The question isn't whether our memories are false, it's how false are our memories," Shaw says, in an interview with Scientific American earlier this year.  "Complex and full false memories (of entire events) are probably less common than partial false memories (where we misremember parts of events that happened), but we already naturally fill in so many gaps between pieces of memories and make so many assumptions, that our personal past is essentially just a piece of fiction."

Nor are they always about small and insignificant pieces of our past.  In a study by Maryann Garry and Matthew P. Gerry, of the University of Wellington (New Zealand) Department of Psychology, the researchers found that complex and detailed false memories could be implanted by the simple expedient of a cleverly doctored photograph -- inducing one test subject to "remember" taking a hot-air balloon ride that never happened.

[image courtesy of the Wikimedia Commons]

I find this deeply unnerving, mostly because of how rock-solid my memories seem to me.  "Of course it happened that way," my brain says to me.  "I remember it.  I can picture it.  It happened."

Shaw and others, however, have conclusively shown that this is a fallacious stance.  "I have always been self-conscious about my autobiographical memories, since I have always been really bad at remembering things that happen in my personal life," Shaw says.  "I am pretty good, on the other hand at remembering facts and information.  This is part of why I was confident my research on creating false memories could work, since if my memory was like this surely there must be others out there whose memories also don't work perfectly."

Which turns out to be an understatement.  "While I was always cautious about memory accuracy (as far as I remember, hah!)," Shaw continues, "now I am convinced that no memories are to be trusted. I am confident that we create our memories every day anew, if ever so slightly.  It's such a terrifying but beautiful notion that every day you wake up with a slightly different personal past."

For me, emphasis on the "terrifying" part, especially considering how much faith most of us have in our memories.  Eyewitness testimony is considered one of the strongest pieces of evidence in courts of law, and the work of Shaw and others has shown that it is in fact one of the weakest.  But on a more personal level, it's distressing to realize that so much of what we think of as our personal history might well be false.  It brings to mind the numerous instances when my wife and I have argued over the way a particular event happened.  Each of us was dead certain we remembered it right.  In fact -- it might be that neither of us was right.

The scariest thing to me is that there seems to be no way to tell the false memories from the accurate ones.  "[O]nce they take hold false memories are no different from true memories in the brain," Shaw says.  "This means that they have the same properties as any other memories, and are indistinguishable from memories of events that actually happened. The only way to check is to find corroborating evidence for any particular memory that you are interested in 'validating'."

Which, of course, isn't always possible.  So the unsettling truth is that what you remember of your past is a patchwork quilt of real events, partially misremembered events, and complete made-up bullshit your brain has invented.  The next time you're arguing with a friend over something in the past...

... remember that.

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.

Many worlds

I've always had a fairly good memory -- for certain things, at least.  I usually lecture my classes without notes, for example.  I find that it keeps my teaching fluid, much more so than it would be if I were just reading from a script.  (Every once in a while, though, the technique fails me, and I have to check something, or simply can't remember a particular term -- an occurrence I'm finding ever more common as I mosey my way through my 50s.)

At the same time, though, I'm constantly aware of how plastic and unreliable human memory is.  We form impressions of events, and sometimes those impressions are actually very far from correct.  The odd thing is that these pseudomemories don't seem inaccurate, or fuzzy.  My personal experience is that memories which are flat wrong seem perfectly solid -- until someone points out that facts demonstrate conclusively that what I'm remembering can't be correct.

It is this seeming certainty that is puzzling, and sometimes alarming.  A study back in 2005 by James Ost, a cognitive psychologist at the University of Portsmouth (England), demonstrated all of this with frightening clarity.  Ost took a group of volunteers in England and in Sweden, and asked them if they'd seen CCTV footage of the 2005 Tavistock Square bombing, when in fact no such footage exists.  50% of the Swedish participants said they had, and a full 84% of the English ones did!  Further, when Ost asked the volunteers who had responded "yes" for details about the video footage, they gave surprising amounts of information.  Ost asked one participant, "Was the bus moving when the bomb went off?" and received the following response: "The bus had just stopped to let two people off, when two women got on, and a man.  He placed the bag by his side, the woman sat down and doors closed.  As the bus left there was an explosion and then everyone started to scream."

So, as unsettling as it seems, a lot of what we remember didn't happen that way, or perhaps didn't happen at all.  Not a pleasant thought, but it seems like it's pretty universal to the way the human mind works.

Ost's study makes what I ran across yesterday all the more bizarre.  On a website called "The Mandela Effect," we are introduced to a woman named Fiona Broome, whose interest lies in exactly the sort of memory side-slips that Ost researched.  Her curiosity about such occurrences started when she realized how many of her acquaintances "remembered" that Nelson Mandela had died in jail -- even recalled details of his funeral from news stories they'd read.  But instead of coming to Ost's conclusion, which is that human memory is simply unreliable, Broome has reached a different explanation.

Broome thinks that these represent memories accessed from alternate realities.

"That’s not a conspiracy theory," Broome writes.  "It’s related to alternate history and parallel realities.  Exploring the quantum / 'Sliders' concept further, I discovered an entire world of shifting realities that people try to reconcile daily...  These aren’t simple errors in memory; they seem to be fully-constructed incidents (or sequential events) from the past.  They exceed the normal range of forgetfulness.  Even stranger, other people seem to have identical memories."

What are these "identical memories" that many people supposedly share?  They include:

• The deaths of Billy Graham, actors Henry Winkler, Shirley Temple, and David Soul, and televangelist Jimmy Swaggart.
• Plots and various other details on Mystery Science Theater and Star Trek: Voyager.
• Details and release dates of the movies Avatar and Terminator.
• Various PS1 games that don't exist.
• The locations of New Zealand and Sri Lanka.

And apparently, Fiona Broome and the others of her mindset actually think that all of this is better explained by their somehow accessing an "alternate universe" than it is by their simply not remembering stuff correctly.

Even if you buy the "many worlds" interpretation of quantum mechanics -- a conjecture which is far from settled amongst physicists, however many plots of science fiction movies depend on its being correct -- there's absolutely no reason to believe that we still have access to alternate timelines once splitting has occurred.  If that were true, and people could jump back and forth between universes, it kind of throws the Law of Conservation of Matter and Energy right out of the window.  And that law pairs up with the Second Law of Thermodynamics as two of the most fundamental building blocks of our understanding of the universe, and -- more importantly -- they are two laws for which no exception has ever been shown.

[image of "Schrödinger's Cat and Universe Branching" courtesy of Christian Schirm and the Wikimedia Commons]

Even ardent many-worlds supporters like Hugh Everett and John Archibald Wheeler believed that once the timeline has forked, the two universes are permanently sealed off from one another.  No information, much less matter and energy, can get from one to the other, which means that if many-worlds is right, there's no way to prove it (this, in fact, is one of the main objections from detractors).  So even though timeline-jumping is a central trope in my novel Lock & Key, I am very much of the opinion that the entire idea rests on a physical impossibility (which is why the novel is filed in the "fiction" section).

Sadly, this leaves Fiona Broome et al. kind of getting sliced to ribbons by Ockham's Razor.  Bit of a shame, really, because it would be cool if we could get a glimpse of alternate universes.  It brings to mind a quote from C. S. Lewis's novel Prince Caspian:

"You mean," said Lucy rather faintly, "that it would have turned out all right – somehow?  But how?  Please, Aslan!  Am I not to know?

"To know what would have happened, child?" said Aslan.  "No. Nobody is ever told that."

It may well be that Broome's conjecture is more appealing than Ost's is; that our memory lapses represent the glittering remains of sideward steps into other worlds instead of simple neural failures.  But unfortunately, Ost's conclusion lines up better with the evidence.  Other studies, showing how easy it is to implant false memories, and how completely convincing those pseudomemories seem, indicate that what's really happening is that we are creating our recollections as we go, and some of them are simply invented from bits and pieces, from suggestions, or out of thin air.

The world, it seems, is far more solid than our memory of it.  So if Sri Lanka appears to have moved to the southeast, as some people apparently believe, then it's much more likely that you simply don't remember your geography very well than it is that you've had a glimpse of an alternate Earth in which the island is anchored elsewhere.