Problems

Drug prevents post-traumatic stress syndrome

January, 2011

A new drug is successful in preventing PTSD in mice if delivered within 5 hours of the trauma.

A mouse study has revealed the brain becomes overly stimulated after a traumatic event causes an ongoing, frenzied interaction between two brain proteins long after they should have disengaged. However, the injection of newly developed drugs into the hippocampus within a five hour window calmed this process, and prevented the development of a post-traumatic fear response.

The new research shows the potential for PTSD occurs when a stressful event causes a flood of glutamate, which then interacts with a second protein (Homer1a). This protein continues to stimulate metabotropic glutamate receptor 5 [mGluR5] after the glutamate has dissipated. The new drugs bind mGluR5 and reverse its activity.

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Tetris can reduce PTSD flashbacks

January, 2011

Playing Tetris shortly after a traumatic event reduced flashbacks, but playing a word-based quiz increased the number of flashbacks.

Following a study showing that playing Tetris after traumatic events could reduce memory flashbacks in healthy volunteers, two experiments have found playing Tetris after viewing traumatic images significantly reduced flashbacks while playing Pub Quiz Machine 2008 (a word-based quiz game) increased the frequency of flashbacks. In the experiments, volunteers were shown a film that included traumatic images of injury.

In the first experiment, after waiting for 30 minutes, 20 volunteers played Tetris for 10 minutes, 20 played Pub Quiz for 10 minutes and 20 did nothing. In the second experiment, this wait was extended to four hours, with 25 volunteers in each group.

In both experiments, those who played Tetris had significantly fewer flashbacks that the other two groups, and all groups were equally able to recall specific details of the film. Flashbacks were monitored for a week.

It is thought that with traumatic information, perceptual information is emphasized over conceptual information, meaning we are less likely to remember the experience of being in a high-speed road traffic collision as a coherent story, and more likely to remember it by the flash of headlights and noise of a crash. This perceptual information then pops up repeatedly in the victim's mind in the form of flashbacks to the trauma causing great emotional distress, as little conceptual meaning has been attached to them. If you experience other events that involve similar information, during the time window in which the traumatic memories are being processed, that information will interfere with that processing.

Thus, the spatial tasks of Tetris (which involves moving and rotating shapes) are thought to compete with the images of trauma, while answering general knowledge questions in the Pub Quiz game competes with remembering the contextual meaning of the trauma, so the visual memories are reinforced and the flashbacks are increased.

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When estrogen helps memory, and when it doesn’t

November, 2010

Recent rodent studies confirm attention and learning is more difficult for women when estrogen is high, but estrogen therapy can help menopausal women — if given during a critical window.

Recent rodent studies add to our understanding of how estrogen affects learning and memory. A study found that adult female rats took significantly longer to learn a new association when they were in periods of their estrus cycle with high levels of estrogen, compared to their ability to learn when their estrogen level was low. The effect was not found among pre-pubertal rats. The study follows on from an earlier study using rats with their ovaries removed, whose learning was similarly affected when given high levels of estradiol.

Human females have high estrogen levels while they are ovulating. These high levels have also been shown to interfere with women's ability to pay attention.

On the other hand, it needs to be remembered that estrogen therapy has been found to help menopausal and post-menopausal women. It has also been found to be detrimental. Recent research has suggested that timing is important, and it’s been proposed that a critical period exists during which hormone therapy must be administered if it is to improve cognitive function.

This finds some support in another recent rodent study, which found that estrogen replacement increased long-term potentiation (a neural event that underlies memory formation) in young adult rats with their ovaries removed, through its effects on NMDA receptors and dendritic spine density — but only if given within 15 months of the ovariectomy. By 19 months, the same therapy couldn’t induce the changes.

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Face-blindness an example of inability to generalize

October, 2010

It seems that prosopagnosia can be, along with perfect pitch and eidetic memory, an example of what happens when your brain can’t abstract the core concept.

‘Face-blindness’ — prosopagnosia — is a condition I find fascinating, perhaps because I myself have a touch of it (it’s now recognized that this condition represents the end of a continuum rather than being an either/or proposition). The intriguing thing about this inability to recognize faces is that, in its extreme form, it can nevertheless exist side-by-side with quite normal recognition of other objects.

Prosopagnosia that is not the result of brain damage often runs in families, and a study of three family members with this condition has revealed that in some cases at least, the inability to remember faces has to do with failing to form a mental representation that abstracts the essence of the face, sans context. That is, despite being fully able to read facial expressions, attractiveness and gender from the face (indeed one of the family members is an artist who has no trouble portraying fully detailed faces), they couldn’t cope with changes in lighting conditions and viewing angles.

I’m reminded of the phenomenon of perfect pitch, which is characterized by an inability to generalize across acoustically similar tones, so an A in a different key is a completely different note. Interestingly, like prosopagnosia, perfect pitch is now thought to be more common than has been thought (recognition of it is of course limited by the fact that some musical expertise is generally needed to reveal it). This inability to abstract or generalize is also a phenomenon of eidetic memory, and I have spoken before of the perils of this.

(Note: A fascinating account of what it is like to be face-blind, from a person with the condition, can be found at: http://www.choisser.com/faceblind/)

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Have I done it?

October, 2010

Watching another person do something can leave you with the memory of having done it yourself.

I’m not at all sure why the researcher says they were “stunned” by these findings, since it doesn’t surprise me in the least, but a series of experiments into the role of imagination in creating false memories has revealed that people who had watched a video of someone else doing a simple action often remembered doing the action themselves two weeks later. In fact in my book on remembering intentions, which includes a chapter on remembering whether you’ve done something, I mention the risk of imagining yourself doing something (that you then go on to believe you have actually done it), and given all the research on mirror neurons, it’s no big step to go from watching someone doing something to remembering that you did it. Nevertheless, it’s nice to get the confirmation.

The experiments involved participants performing several simple actions, such as shaking a bottle or shuffling a deck of cards. Then they watched videos of someone else doing simple actions—some of which they had performed themselves and some of which they hadn’t. Two weeks later, they were asked which actions they had done. They were much more likely to falsely remember doing an action if they had watched someone else do it — even when they had been warned about the effect.

It seems likely that this is an unfortunate side-effect of a very useful ability — namely our ability to learn motor skills by observing others (using the aforesaid mirror neurons) — and there’s probably not a great deal we can do to prevent it happening. It’s just a reminder of how easy it is to form false memories.

Reference: 

[1839] Lindner, I., Echterhoff G., Davidson P. S. R., & Brand M.
(2010).  Observation Inflation.
Psychological Science. 21(9), 1291 - 1299.

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Adults recall negative events less accurately than children

August, 2010

A word experiment shows that unpleasant or traumatic events are likely to be inaccurately remembered, and this memory distortion increases with age. The findings have implications for eyewitness testimony.

Findings that children are less likely than adults to distort memories when negative emotions are evoked has significant implications for the criminal justice system. Experiments involving children aged seven and 11, and young adults (18-23) found that when they were shown lists of closely related emotional words (e.g. pain, cut, ouch, cry, injury), they would tend to mistakenly remember a related word (e.g. hurt) although it had not been present. Despite the prevailing theory that being involved in a very negative experience focuses your mind and helps you notice and remember details, words that had negative emotional content produced the highest levels of false memory. With arousal (such as would be evoked in a traumatic experience), memory was distorted more. These tendencies increased with age.

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[1670] Brainerd, C. J., Holliday R. E., Reyna V. F., Yang Y., & Toglia M. P.
(2010).  Developmental reversals in false memory: Effects of emotional valence and arousal.
Journal of Experimental Child Psychology. 107(2), 137 - 154.

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1 in 40 of us really can multitask

March, 2010

A study assessing multitasking ability has found that a very few (5 out of 200) were unaffected by doing two complex tasks simultaneously (indeed their performance on the memory task improved!).

A study assessing the performance of 200 people on a simulated freeway driving task, with or without having a cell phone conversation that involved memorizing words and solving math problems, has found that, as expected, performance on both tasks was significantly impaired. However, for a very few, performance on these tasks was unaffected (indeed their performance on the memory task improved!). These few people — five of them (2.5%) — also performed substantially better on these tasks when performed alone.

Reference: 

Watson, J.M. & Strayer, D.L. 2010. Supertaskers: Profiles in extraordinary multitasking ability. Psychonomic Bulletin and Review. In Press.

Full text is available at http://www.psych.utah.edu/lab/appliedcognition/publications/supertaskers...

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Interruptions associated with medication errors by nurses

April, 2010

A study of medication administrations in hospitals has found scarily high rates of procedural and clinical failures, of which 2.7% were considered to be major errors — which were much more likely to occur after interruptions, particularly repeated interruptions. Nurse experience provided no protection and indeed was associated with higher procedural failure rates (common with procedural failures — expertise renders you more vulnerable, not less).

As we all know, being interrupted during a task greatly increases the chance we’ll go off-kilter (I discuss the worst circumstances and how you can minimize the risk of mistakes in my book Planning to remember). Medication errors occur as often as once per patient per day in some settings, and around one-third of harmful medication errors are thought to occur during medication administration. Now an in-depth study involving 98 nurses at two Australian teaching hospitals over 505 hours has revealed that at least one procedural failure occurred in 74.4% of administrations and at least one clinical failure in 25%. Each interruption was associated with a 12.1% increase in procedural failures and a 12.7% increase in clinical errors. Procedural failures include such errors as failure to check patient's identification, record medication administration, use aseptic technique; clinical failures such errors as wrong drug, dose, or route. Interruptions occurred in over half of the 4000 drug administrations. While most errors were rated as clinically insignificant, 2.7% were considered to be major errors — and these were much more likely to occur after interruptions, particularly after repeated interruptions. The risk of major error was 2.3% when there was no interruption; this rose to 4.7% with four interruptions. Nurse experience provided no protection against making a clinical error and was associated with higher procedural failure rates (this is common with procedural failures — expertise renders you more vulnerable, not less).

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Biased retellings of events yield biased memories

Journal Article: 

Tversky, Barbara & Marsh, Elizabeth J. 2000. Biased retellings of events yield biased memories. Cognitive Psychology, 40, 1-38.

  • The vividness and clarity of a memory is no guarantee of its accuracy
  • Memories of dramatic public events have no particular status in memory, and are as likely as any other memory to be inaccurate
  • The retelling of events changes our memory of them
  • If we perceive an event from a particular biased perspective, or adopt a biased perspective when retelling the event, it will distort our memory of the event accordingly

When we tell people about things that have happened to us, we shape the stories to our audience and our purpose. The amount of detail we give and the slant we give to it depends on our perceptions of our audience and what we think they want to hear. Does this change our memory for the event? Certainly we are all familiar with the confusion we get after we have been telling a particular story for years — we’re no longer sure what really happened and what we’ve added or subtracted to make a better story.

There is a popular misconception that dramatic public events such as earthquakes, the Challenger disaster, JFK’s assassination, etc, are given a special status in memory (“flashbulb memories”). It is true that people often have very clear memories of these events, but research has shown that such memories are as likely as any other event memory to be inaccurate1. Vividness, I regret to say, is no reliable measure of the accuracy of a memory.

This study used two invented stories rich in detail that could be told from more than one point of view. After studying one or other of the stories, subjects were asked to write a letter about one of the characters, the letter to be biased either for or against the character. Control subjects were simply asked to write as much as they could remember about the specified character. Subjects were later tested on their recall of the original story. Different aspects of memory were investigated in a series of four experiments.

It was found that subjects who wrote the biased letters recalled more information about the specified character that was related to the biased perspective. Their recall of the other character in the story was unaffected. They also added more (erroneous) details about the character — these errors being consistent with the particular bias they’d been given.

Although selective rehearsal (the fact that these subjects had had an opportunity to rehearse the information that supported the appropriate bias, at the expense of other information) plays a part in this, biased memory was found even when the subjects, in the fourth experiment, were asked to write a biased evaluation instead of a biased retelling (to avoid rehearsal of specific items).

The slant we give to information guides our encoding of the memory, the way we organize it, and the connections we make to other memories.

References

1. Neisser, U. & Harsch, N. 1992. Phantom flashbulbs: False recollections of hearing the news about Challenger. In E. Winograd & U. Neisser (eds.) Affect and accuracy in recall: Studies of 'Flashbulb Memories'. New York: Cambridge University Press.

Larsen, S.F. 1992. Potential flashbulbs: Memories of ordinary news as the baseline. In E. Winograd & U. Neisser (eds.) Affect and accuracy in recall: Studies of 'Flashbulb Memories'. New York: Cambridge University Press.

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