Category: Remembering

The Neurocritic covers some fascinating research on how marathon runners could be a scientific window into the neuropsychology of trauma owing to the fact that they experience extremely high levels of the stress hormone cortisol.

In their study, psychologists Teal Eich and Janet Metcalfe note that cortisol levels recorded 30 minutes after a marathon have been found to be similar to those in soldiers during military training and interrogation, rape victims just after the attack, severe burn injury patients and first-time parachute jumpers.

This suggests that marathon runners could be studied in a more systematic way than would would be ethical with victims of trauma, giving an important insight into the brain under extreme stress.

Eich and Metcalfe were particularly interested in the effect of stress on memory and wanted to see if there were any differences between explicit memory – memories that you can consciously call to mind, and implicit memory – the influence of past information on a task even if you’re not aware of doing any remembering.

They tested a group of runners about half an hour after they completed a marathon and a group who were just about to run a marathon.

In comparison to the about-to-runs, those who had completed the marathon had worse explicit memory but better implicit memory. In other words, their conscious memory was reduced but their unconscious memory seemed to be sharper.

This is interesting because chronically high cortisol levels from trauma are thought to affect the hippocampus, a brain area known to be key in conscious memory. The researchers suggest that a similar process may be temporarily reducing explicit memory in runners.

The authors are a little more cautious in suggesting why implicit memory may have been improved, but one possibility is that cortisol is known to affect fear conditioning – the unconscious linking of fright with the situation it occurred in.

Interestingly, this is known to work differently in men and women. Cortisol boosts unconscious fear learning in men, but not women. The researchers didn’t compare male and female marathon runners directly, but it would be interesting to know whether general unconscious learning that wasn’t associated with fright was also sex-specific in their study.

There’s more on the research over at The Neurocritic and the full text of the study is available online as a pdf if you want an in-depth look at the experiment.

Link to great write-up from The Neurocritic.
pdf of study.
Link to PubMed entry for same.

Newsweek has an interesting article about the reality of unconscious plagiarism – otherwise known as ‘cryptomnesia’.

The article describes apparently genuine cases in terms of source memory – the ability to not only to remember information but also where it came from. When you remember a great idea, was it one of yours, it did you read it in a book, or hear it from a friend?

In the lab this has usually been tested by relatively simple experiments where participants are asked to read out words, imagine themselves reading out words and hear words being read out.

They’re then shown another list, and they have to say whether they’ve encountered the word before and, if so, did they hear it, read it or imagine it.

There are many variations on this simple idea, but all of which show that we routinely mistake information from other people as something we generated ourselves.

Psychologist Marcia Johnson has done a huge amount of work on how we monitor the source of our memories and how distortions affect what she calls ‘reality monitoring’.

It turns out that memories don’t have a specific source tag, like a mental label. We infer where they came from based on their content. There are many things have been found to be important, but even something as simple as the sensory vividness of the memory is known to have a big effect.

For example, people who have very vivid mental images have been found to be more likely to misattribute the source of memories for this reason.

So the idea is that sometimes we present other people’s ideas as our own, not because we’re being deliberately dishonest, but because we genuinely think we came up with it in the first place because of source memory failure.

The Newsweek article covers how this applies to writers and journalists and some of the recent research which tackles exactly these sort of memory distortions.

However, it doesn’t mention perhaps the most famous of cryptomnesia – where a judged ruled that ex-Beatle George Harrison had unconsciously plagiarised the Chiffons’ He’s so Fine in his own track My Sweet Lord.

And this is exactly where it gets a bit murky, because it’s never clear whether someone has unconsciously plagiarised, or just plagiarised, because it relies on making a judgement about someone else’s intentions.

Link to Newsweek article on cryptomnesia.

Wired Science has an interesting interview with Oxford neuroethicist Anders Sandberg about the future of drugs that can reduce the emotional impact of traumatic memories.

The interview uses the term ‘memory editing’ which is not a great label for these drugs, such as beta-blocker propranolol, which largely work by reducing the emotional ‘kick’ stored with a memory of a painful or traumatic experience when taken after the experience or during recall.

This is something that is often misreported by the mainstream media who often starting going off on one about ‘memory erasing’ drugs and the like.

However, it is also not true that propranolol solely effects the emotional aspects. Careful reading of the studies show that people treated with the compound do typically show a slight reduction in their actual memory for traumatic events.

But the interview makes the interesting point that maybe we’re a bit too focused on removing or reducing memories, the problem of inducing false memories is probably more serious:

Wired.com: I’ve asked about memory removal ‚Äî but should the discussion involve adding memories, too?

Sandberg: People are more worried about deletion. We have a preoccupation with amnesia, and are more fearful of losing something than adding falsehoods.

The problem is that it’s the falsehoods that really mess you up. If you don’t know something, you can look it up, remedy your lack of information. But if you believe something falsely, that might make you act much more erroneously.

You can imagine someone modifying their memories of war to make them look less cowardly and more brave. Now they’ll think they’re a brave person. At that point, you end up with the interesting question of whether, in a crisis situation, they would now be brave.

Link to ‘The Messy Future of Memory-Editing Drugs’.

There’s an interesting short research report in Cortex about how a national symbol adopted in Italy after the 1980 terrorist bombing of Bologna train station likely instilled a false memory about the following 16 years.

On the morning of August 2nd, 1980, at 10.25, a bomb exploded in Bologna Centrale station, killing eighty-five people wounding over 200.

The blast also stopped the large station clock on the side of the building at the moment of the explosion, freezing the hands in the 10.25 position. Shortly afterwards, the clock was repaired and it continued to function normally for 16 years.

However, when it broke in 1996, it was decided to leave the clock in its broken state and permanently set the hands at 10.25 in remembrance of the tragedy, owing to the fact that the image of the frozen clock had been widely used in commemorations during the intervening years.

A group of Italian psychologist were aware that repetition tends to cause false memories and decided to test residents of Bologna, all familiar with the station, for their memory of the clock.

What they found was that the majority of people falsely remembered that the clock had been frozen since the bombing and never worked since, despite the fact that this was never the case.

This included those who had regularly seen the clock working fine, presumably on a daily basis, owing to the fact that they worked at the station during the 16 intervening years.

Of the 173 participants who knew that the clock is now stopped, 160 (92%) stated that the clock has always been broken. 127 (79%) further claimed to have seen it always set at 10.25, including all 21 railway employees. Most interviewees did not know that the clock had been working for over 16 years and stated that it had always been broken.

From the 173 people who knew that at the time of testing the clock was stopped, a subgroup of 56 citizens who regularly take part in the annual official commemoration of the event has been further considered: only six (11%) of them correctly remember that the clock had been working in the past.

The findings are an interesting parallel to a study published last year on the London bombings. The researchers asked participants about their memories of seeing TV footage of the bus exploding in Tavistock Square.

Despite the fact that no such footage exists and no reconstruction was ever shown on TV, 40% of British participants ‘remembered’ seeing it and produce ‘details’ of the coverage when asked.

Link to study on Bologna bombings.
Link to PubMed entry for same.
Link to summary of London bombings study.

New Scientist has an excellent article on the neuroscience of deja vu, tackling how our brain can generate the anomalous feeling that we are reliving an event when it has happened for the first time.

The article tackles both experiments that try to trigger and measure deja vu in healthy participants, as well as in people who experience, sometimes permanent, deja vu because of epilepsy of brain injury.

There is one slightly awkward bit in the article however.

One possibility is that d√©j√† vu is based on a memory fragment that comes from something more subtle, such as similarity between the configuration or layout of two scenes. Say you are in the living room of a friend’s new house with the eerie feeling that you have been there before, yet knowing you can’t possibly. It could be just that the arrangement of furniture is similar to what you have seen before, suggests Cleary, so the sense of familiarity feels misplaced…

Although the familiarity idea appeals to many, Moulin, for one, is not convinced. His scepticism stems from a study of a person with epilepsy that he conducted with Akira O’Connor, now at Washington University in St Louis, Missouri. This 39-year-old man’s auras of d√©j√† vu were long-lasting enough to conduct experiments during them. The researchers reasoned that if familiarity is at the root of d√©j√† vu, they should be able to stop the experience in its tracks by distracting the man’s attention away from whatever scene he was looking at. However, when he looked away or focused on something different, his d√©j√† vu did not dissipate, and would follow his line of vision and his hearing, suggesting that real familiarity is not the key. The fact that an epilepsy aura can cause d√©j√† vu at all suggests that it is erroneous activity in a particular part of the brain that leads to misplaced feelings of familiarity, suggests Moulin.

This dichotomy is interesting because it implies that ‘brain activity’ and ‘misplaced familiarity’ are somehow separate, when we know each can just be descriptions of the same thing on different levels of interpretation.

However, it also implies that deja vu can only be caused in one particular way, when it could be caused by many different processes.

For example, think about trying to understand why someone got angry. We could be studying one person who gets angry when his football team loose, another when he is wrongly accused and another when he has a seizure in his limbic system.

You could use each one of these explanations to say that the other explanation is wrong if you believed that anger could only be caused in one way.

However, if we accept that it is an experience described at the level of psychology or behaviour there could be many ways of explaining it, and many paths that lead to the same experience, each cause does not cancel the other out.

Like deja vu and probably many other experiences, there are many causes and ways of explaining causes for the same phenomena.

Link to NewSci article ‘D√©j√† vu: Where fact meets fantasy’.

The latest edition of Neuron has a fantastic tribute to the recently departed amnesic Patient HM, “probably the best known single patient in the history of neuroscience”, covering the scientific work he participated in and what it has told us about the structure of memory.

The piece is by respected memory researcher Larry Squire and he tackles HM’s personal history while also reviewing his contributions to science through numerous landmark studies.

It can be said that the early descriptions of H.M. inaugurated the modern era of memory research. Before H.M., due particularly to the influence of Karl Lashley, memory functions were thought to be widely distributed in the cortex and to be integrated with intellectual and perceptual functions.

The findings from H.M. established the fundamental principle that memory is a distinct cerebral function, separable from other perceptual and cognitive abilities, and identified the medial aspect of the temporal lobe as important for memory.

The implication was that the brain has to some extent separated its perceptual and intellectual functions from its capacity to lay down in memory the records that ordinarily result from engaging in perceptual and intellectual work.

The article is fascinating not least because it dispels a few common myths about HM – such as the original study showed the hippocampus was necessary for memory when HM also had the amygdala and parahippocampal gyrus removed and so it wasn’t possible to say which were most important.

It also notes that the original studies over-stated how much brain was removed owing to the basic knowledge of neuroanatomy that existed at the time.

Link to ‘The Legacy of Patient H.M. for Neuroscience’.
Link to PubMed entry for same.

Dream researchers in the 1950s concluded that people typically dreamed in black and white whereas modern dream research reports most people dream in colour. Philosopher Eric Schwitzgebel discusses this curious finding in a 2002 article, arguing that it is unlikely dreaming has changed so radically and that this is likely evidence of how bad we are at introspection into our dream lives.

Schwitzgebel discusses a whole range of theories and ideas, but begins by summarising the evidence from a time when it was largely assumed that people dream in monochrome:

In 1951, Calvin S. Hall announced in Scientific American that 29% of dreams are either entirely colored or have some little bit of color in them (Hall, 1951). He called such dreams ‘technicolored’, thereby explicitly comparing them to the colored movies that were becoming increasingly prevalent in the 1940s and ’50s, and implicitly contrasting them with lower-tech black and white movies and dreams.

Some of Hall’s contemporaries might have thought him too generous in his estimation of the proportion of colored to black and white dreams. Tapia, Werboff and Winokur (1958) found that only about 9% of a sample of people reporting to the hospital at Washington University in St. Louis for non-psychiatric medical problems reported having colored dreams, compared with 12% of neurotic men and 21% of neurotic women. Middleton (1942) found that 40% of his college sophomores claimed never to see colors in their dreams, 31% claimed rarely to do so, and only 10% claimed to do so frequently or very frequently.

The first objection you might think of is that perhaps these results are accurate, owing to the fact people watched lots of black and white TV and films.

But in an age when people still spent a relatively small proportion of their time in the cinema or in front of the TV (which only had restricted broadcasts) it is unlikely to account for the virtual ‘absence’ of coloured dreaming, especially considering that ‘real life’ is experienced in colour.

One of the most interesting hypothesis tackled by the article is that dreams are like narratives, and do not necessarily have colour, but black and white media might just have led people to interpret their dreams in this way.

Consider, as an analogy, a novel. While novels surely are not in black and white, it also seems a little strange to say that they are ‚Äòin color‚Äô. Certainly novels make fictional attributions of color (‚Äòshe strode into the room in a dazzling red dress‚Äô) and refer to objects that normally have a particular color (‚Äòshe promptly chopped a carrot‚Äô). Maybe it makes sense to describe such fictional claims as ‚Äòin color‚Äô or partly in color. However, most elements of most scenes in novels do not have determinate colors in that way…

If you find yourself disinclined to think that novels, or the images evoked by novels, are properly described as being either in black and white or in full color, then you might likewise find yourself hesitant to apply the terms ‘black and white’ or ‘colored’ to dreams. Perhaps dream-objects and dream-events are similar to fictional objects and events, or to the images evoked by fiction, in having, typically, a certain indeterminacy of color, neither cerise nor taupe nor burnt umber, nor gray either.

The article goes on to suggest that this reconstructive aspect is a core feature of consciousness and that is further evidence that we are just not very good at introspecting our own minds because as soon as we do, we alter the contents of what we’re attempting to experience.

pdf of ‘Why did we think we dreamed in black and white?’

The tip-of-the-tongue state is a common experience where you know you know something but can’t quite bring it to mind. This everyday experience has told us a great deal about how the mind and brain work, as explored in an article for the Boston Globe.

It’s a paradoxical experience if you think about it. You know something, but you can’t remember it.

Just this tells us that the storage of information and the ability to access it are distinct in the brain.

It also tells us that the brain must have ways of monitoring itself and communicating how successfully it carries out its operations to the conscious and unconscious mind.

This is known as ‘metacognition‘ and is one of the most important concepts in modern psychology.

The Boston Globe article (by Jonah Lehrer of the Frontal Cortex blog) is a remarkably lucid exploration of exactly this topic, looking at how it has been studied in everything from lab studies to people with brain injury who suffer near permanent tip-of-the-tongue states.

Link to Boston Globe article ‘What’s that name?’.

Thanks to Aaron and Frontal Cortex for simultaneously alerting us to this fantastic animation that recounts a charming real life case of a false memory.

Families are like incubators for false memories because each family has its favourite stories, anecdotes and foundational myths that get passed on, retold and molded in the retelling, like an intergeneration game of Chinese whispers.

I have many early memories that I simply don’t know whether I genuinely remember, or I just think I do, because I’ve heard stories or seen the photos so many times.

I love listening to families talk about memories, because its fascinating to hear how recollections can vary, each highlighting a different aspect, as well as how they resolve conflicting accounts.

The animation shows exactly this process in action, showing us that remembering is more than just an individual process, it’s often a group activity.

Link to This American Life animation on memory.

The legal system works on a principal of innocent until proven guilty by the evidence presented in court, but Cognitive Daily covers several studies that shown our memory of the evidence is affected by moral judgements of the person in question.

With their trademark clarity, CogDaily discuss a study [pdf] by psychologist David Pizarro that found if participants were told about man leaving a restaurant without paying, they remembered the unpaid bill being more expensive if they were told he treated the waiters rudely, than if they were told he was generally a responsible person.

The study is reminiscent of a famous experiment by a young Elizabeth Loftus called Reconstruction of Automobile Destruction.

It was simple but elegantly designed. Groups of people were shown clips of cars crashing and then asked how fast the cars were travelling, but with different verbs in the question.

For example, some people were asked how fast the cars were travelling when they “smashed” into each other, others how fast when they “bumped” into each other, others how fast when they “contacted” with each other, and so on.

Loftus found that simply asking the questions with a different verb altered people’s memories of the speed of the crash – like so:

“smashed” : 40.8 miles per hour
“collided” : 39.3 miles per hour
“bumped”: 38.1 miles per hour
“hit” : 34 miles per hour
“contacted” : 31.8 miles per hour

Needless to say, these sorts of tricks have been used by lawyers ever since.

Link to CogDaily on moral blame can change the memory of a crime.
pdf of full-text paper.
Link to Wikipedia page Loftus’s car crash study.

Psychologist Yacov Rofé has written a damning article in the Review of General Psychology summarising the evidence from studies on the cognitive science of memory and arguing that the repression of memory, as described by Freud, doesn’t exist.

Rofé is careful to point out that Freud’s ideas about the repression of memory were not that we can deliberately forget or ignore traumatic experiences (as is often assumed by both professionals and lay people), but that process is supposedly unconscious (and so not deliberate) and that it was ‘pathogenic’ – in other words, a cause of mental distress and mental illness.

Rofé also notes that psychoanalysis was assumed to make people better by uncovering and lifting repression to make people better adjusted (although this has largely been rejected by modern therapists).

In contrast to these theories, Rofé cites evidence that people tend to remember rather than repress traumatic experiences, that banishing unpleasant memories tends to be a useful way of coping for many people (although interestingly, probably bad for physical health), that there is no evidence for unconsciously motivated forgetting, and that psychoanalytic therapy doesn’t seem to work by ‘lifting repression’.

In the article, Rofé has a bit of a tendency to suggest that supporting evidence that can be equally explained with a non-Freudian theory is evidence against Freud, when it fact it’s likely to support both explanations equally.

Nevertheless, he makes a strong case, largely based on the limited amount of supporting evidence that does actually exist.

However, I suspect this won’t be the end of the argument, as most debates concerning Freud centre as much around agreeing on what the terms mean, as applying data to their truth.

 
Link to abstract of scientific article.
pdf of full-text article.

PsyBlog has just finished its series on the ‘seven sins of memory’ that fade and distort what we try to remember, based on memory researcher Dan Schacter’s book on the same name.

The ‘seven sins’ are:

1. Transience
2. Absent-Mindedness
3. Blocking
4. Misattribution
5. Suggestibility
6. Bias
7. Persistence

And PsyBlog looks at each one, discussing what research has told of us about this particularly memory difficulty and how it affects our record of things past.

If you’re interested in reading more, Schacter’s 1999 book comes highly recommended.

Link to PsyBlog on the ‘Seven Sins of Memory’.

Neurophilosophy has a great write-up of the recent finding that deep brain stimulation boosted memory function in a patient undergoing brain surgery to treat morbid obesity.

I’ve only just got round to having a look at the scientific paper myself, and the summary on Neurophilosophy captures the main themes beautifully, and is some of the best coverage I’ve read so far.

A couple of things stand out for me.

Firstly, the patient was given a last-ditch experimental treatment for obesity by having an electrode planted in the ventral hypothalamus, a deep brain structure, to try and reduce his appetite.

The hypothalamus is involved in regulating a number of essential bodily functions and most pertinently, contains glucoreceptors – cells that detect levels of glucose in the body to regulate feeding and appetite.

A lot has been written about the role of ‘mechanical’ models of the mind and brain in undermining our sense of free will and responsibility for our actions.

This case suggests that we’ve now got to the stage where an inability to control a biological urge which negatively affects few people except the patient himself, is reason enough to consider neurosurgery.

I wonder whether deep brain stimulation for people who can’t give up cigarettes, alcohol or self-harm will be next.

Secondly, the immediate effect of the stimulation on the patient, who was flooded with numerous vivid memories, is quite striking:

Unexpectedly, the patient reported sudden sensations that he described as déjà vu with stimulation of the first contact tested (contact 4: 3.0 volts, 60-microsecond pulse width [pw], and 130Hz). He reported the sudden perception of being in a park with friends, a familiar scene to him. He felt he was younger, around 20 years old. He recognized his epoch-appropriate girlfriend among the people. He did not see himself in the scene, but instead was an observer. The scene was in color; people were wearing identifiable clothes and were talking, but he could not decipher what they were saying. As the stimulation intensity was increased from 3.0 to 5.0 volts, he reported that the details in the scene became more vivid.

This is a strikingly similar experience to the memories triggered by electrical stimulation of the surface of the temporal lobe reported by legendary Canadian neurosurgeon Wilder Penfield in the 50s and 60s:

The other response is an activation of the stream of past experience. This is what the patient often refers to as a ‘flash-back’ to his own past. When the electrode is applied, he may exclaim in surprise, as the young secretary, M M, did: ‘Oh, I had a very, very familiar memory, in an office somewhere. I could see the desks. I was there and someone was calling to me, a man leaning on a desk with a pencil in his hand.’ Or the patient may call out in astonishment, as J T did (when the current was switched on without his knowledge): ‘Yes, Doctor, yes, Doctor! Now I hear people laughing – my friends in South Africa … Yes, they are my two cousins, Bessie and Ann Wheliaw.’

However, despite testing over 600 patients in this way, less than 8% had the experience of electrically triggered memories, and the effect has not been reliably replicated by modern researchers.

This suggests that the flood of memories triggered by stimulating the hypothalamus in this new study, perhaps may not happen in all people.

Of course the big finding in this new study was not the triggered memories, but that when the stimulation was switched on for longer periods, the patient did much better in memory tests.

It will be interesting to see whether this general effect on memory is perhaps as unpredictable across individuals as electrically evoked memories have proved to be in the past.

Link to Neurophilosophy post on the new study.
Link to abstract of scientific paper.
Link to Penfield’s paper (with evoked memory memory examples).

Research just published in neuroscience journal Neuron has discovered some of the brain networks behind post-hypnotic amnesia. Importantly, the study might give us an insight into how memories are repressed from consciousness.

Psychogenic amnesia is a type of memory disorder where there is no brain damage to explain the memory loss. Unlike amnesia after brain injury, which usually causes an inability to form new memories, psychogenic amnesia typically results in the person being unable to remember past events.

Most memory research involves comparing how well people recognise or recall information that they’ve been shown earlier.

One of the difficulties in studying psychogenic amnesia is that you’re never sure whether the memories you’re asking about were taken in, but are inaccessible, or whether the person simply didn’t register the information in the first place.

Amnesia caused by hypnosis is remarkably similar to psychogenic amnesia in many ways, but has the advantage of being temporary and reversible.

This is important because it allows researchers to show people information, then induce hypnotic amnesia and check memory, and then reverse the effects and check memory again.

The final memory check shows that the person genuinely took the information in to start with, so you know that the amnesia was for memories that were definitely there already.

Post-hypnotic amnesia is where a suggestion is given during hypnosis that the person won’t remember a specific event after the hypnosis is over. Because hypnotisability varies between individuals, it doesn’t work for everybody, but for those who experience this type of temporary memory loss, the effect can be quite dramatic.

In an initial session, researchers showed high and low hypnotisable participants a 45 minute film which they were told to remember.

A week later, they were put in an fMRI scanner, hypnotised and told to forget the film when the hypnosis was over. Crucially, they were told that their memories would return when given a specific command.

They were then scanned while being asked “yes/no” questions about both the film itself and other details about the initial session (such as whether the door to the testing room was open).

Unlike facts about the film, the participants were never told to forget these other details, allowing the researchers to test how specific the amnesia was.

The ‘hypnosis resistant’ low hypnotisable participants were equally good at recalling facts about the film and the testing session.

For high hypnotisable participants, although they were good at remembering session details, they were no better than chance at answering the questions about the film. In other words, they would have got the same number of questions right if they flipped a coin – suggesting their memory was quite impaired.

When given the command to remove the amnesia, the high hypnotisable participants could then recall the film as well as the others.

(Partly owing to the scepticism about hypnosis, the researchers also tested another group of people who were told just to pretend to be hypnotised. They performed quite differently – vastly exaggerating their memory difficulties – indicating that the high hypnotisable participants weren’t faking or ‘conforming’).

When trying to recall information when post-hypnotic amnesia was in effect, activity in the temporal lobes and occipital lobes was reduced, while activity in part of the frontal lobes increased.

The areas of the temporal and occipital lobes are known to be involved in dealing with factual and visual information, while the frontal lobes are known to be involved in coordinating other brain areas.

In this case, they seem to be inhibiting the function of other areas, perhaps preventing recall and explaining the amnesia.

Interestingly, when the amnesia was reversed, brain circuits involved in long-term memories became more active as the participants were able to answer questions.

This study might explain how psychogenic amnesia works. Perhaps this syndrome results from the same brain mechanism being ‘locked’ in place, persistently ‘repressing’ memories.

In fact, there’s a whole range of apparently neurological problems but where the person has no recognisable brain damage. These usually get diagnosed as conversion disorder and can involve everything from blindness to paralysis.

Two studies have just come out which point in the same direction as this hypnosis study.

In one, several patients with structurally normal brains were found to have under-activation in certain areas corresponding to their conversion disorder paralysis.

In another, when a patient with conversion disorder was asked to recall the traumatic event which triggered her paralysis, brain activation suddenly dropped in the brain areas that controlled movement in her immobile limbs.

What these studies are suggesting is that problems can arise in the operation of seemingly intact brains that can lead to what appear to be neurological problems.

An analogy might be that while the roads are intact, traffic jams can still bring a city to a standstill. The trick, of course, is to get the traffic flowing again.

The more we understand about how the flow gets disturbed, the more likely we are to help patients get things running smoothly again.

Link to abstract of post-hypnotic amnesia study.
Link to write-up of study from Science News.

Harvard Magazine has an interesting article on whether it is possible to repress memories to force them into the unconscious.

As well as discussing the phenomenon, it also updates us on the challenge put forward by the McLean Hospital Psychiatry Lab: find a single account of repressed memory, fictional or not, before the year 1800 and win $1000.

It turns out, the $1000 dollars has just been awarded, although the account only sneaked past the post – it was from 1786.

The point of the challenge was because the McLean lab suspect that repressed memories, also called ‘dissociative amnesia’, are a ‘culture bound syndrome‘ – in other words, they’re so heavily influenced by cultural ideas that they are not a universal feature of the human mind and brain.

If they are a universal human feature you’d expect them to be reported throughout history, but it turns out that there are no clear reports of anyone repressing a memory, either in historical writing or in fiction, until the late 1700s.

Their paper [pdf] on culture, dissociative amnesia and their challenge, was published just before they awarded the prize, so doesn’t include the winning account, but discusses the cultural influences on this controversial concept.

As well as being enormously good fun, their challenge is an interesting way of gathering date to inform a hot topic in psychology.

Link to Harvard Magazine article on repressed memory and culture.
pdf of paper ‘Is dissociative amnesia a culture-bound syndrome?’.
Link to McClean Psychiatry Lab challenge page with entries.

In George Orwell’s dystopian novel, 1984, Winston Smith works in the Ministry of Truth retouching photographs to remove people from the record of history. A recent psychology study suggests that these manipulations may change more than the historical record, they could affect our collective memories of what actually happened.

In the study, led by Italian psychologist Dario Sacchi, participants were shown two photographs; one from the 1989 Tiananmen Square protests and another from a 2003 protest in Rome against the Iraq war.

What they didn’t know was that some participants saw doctored versions of either one or both of the photographs. The image on the left demonstrates that a crowd was added to the Tiananmen Square image. With the Rome photo police and aggressive-looking demonstrators were added to the image of peaceful protesters.

To test whether people perceived the photos as genuine or not without giving the game away, the researchers asked participants how familiar they were with the image.

Both groups rated the Tiananmen Square photo as equally familiar, suggesting few picked up on the changes.

Interestingly, participants rated the altered Rome photo as less familiar, but when given a chance to comment, no-one suggested it was fake, with some suggesting that their memory of the protest being peaceful, rather than the photo, must be mistaken.

The participants were then asked to answer questions about the events from their memories of what happened.

Those who saw the altered Tiananmen Square image remembered more people being there, those who saw the Rome image remembered it as more violent, more negative, and recalled more property being damaged and confrontations with the police.

When the experiment was run again, participants additionally rated themselves as less likely to attend a demonstration in future.

The study has obvious implications for propaganda and the paper spends much time discussing the possible impact of doctored photos on public opinion.

Combined with some earlier studies that suggest that people often believe initial false news reports even when they’re aware of them being falsified, you can see how the media has a powerful influence over our remembered realities.

Link to study abstract.
Link to write-up from LiveScience.