What working memory does

March 2007

Executive function as important as IQ for math success

A study of 141 preschoolers from low-income homes has found that a child whose IQ and executive functioning were both above average was three times more likely to succeed in math than a child who simply had a high IQ. The parts of executive function that appear to be particularly linked to math ability in preschoolers are working memory and inhibitory control. In this context, working memory may be thought of as the ability to keep information or rules in mind while performing mental tasks. Inhibitory control is the ability to halt automatic impulses and focus on the problem at hand. Inhibitory control was also important for reading ability. The finding offers the hope that training to improve executive function will improve academic performance.
The research was published in the February issue of Child Development. Full reference
http://www.sciam.com/article.cfm?articleID=90377FAE-E7F2-99DF-3A1204FC5F2BF0F7

March 2006

Learning and working memory

A 3-year research project on Working Memory and Cognition has reached its conclusion. The association between effective language learning and good short-term memory is, it seems, not a causal relationship. It is not that a good short-term memory is a prerequisite for long-term learning; it is that both short-term and long-term memory tasks tap the same ability to create representations of sufficient quality to support the maintenance of several of them at once.
Another finding is that metaphoric language often puts greater stress on working memory and so is harder to process than literal language.
Another study looked at differences between the abilities of musicians and persons who did not have music as an active hobby to remember series of notes presented in succession on a computer screen. The results show how expertise makes it possible to apparently bypass working memory limits, even when the memory items cannot be grouped into simple categories.
http://www.eurekalert.org/pub_releases/2006-03/uoh-nrd031306.htm
http://www.sciencedaily.com/releases/2006/03/060320084440.htm

working memory capacity

August 2009

Ability to ignore distraction most important for attention

Confirming an earlier study, a series of four experiments involving 84 students has found that students with high working memory capacity were noticeably better able to ignore distractions and stay focused on their tasks. The findings provide more evidence that the poor attentional capacity of individuals with low working memory capacity result from a reduced ability to ignore attentional capture (stimuli that involuntarily “capture” your attention, like a loud noise or a suddenly appearing object), rather than an inability to focus.
The report appeared in the July 8 issue of the Journal of Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2009-08/uoo-bbo080609.php

April 2009

Individual differences in working memory capacity depend on two factors

A new computer model adds to our understanding of working memory, by showing that working memory can be increased by the action of the prefrontal cortex in reinforcing activity in the parietal cortex (where the information is temporarily stored). The idea is that the prefrontal cortex sends out a brief stimulus to the parietal cortex that generates a reverberating activation in a small subpopulation of neurons, while inhibitory interactions with neurons further away prevents activation of the entire network. This lateral inhibition is also responsible for limiting the mnemonic capacity of the parietal network (i.e. provides the limit on your working memory capacity). The model has received confirmatory evidence from an imaging study involving 25 volunteers. It was found that individual differences in performance on a short-term visual memory task were correlated with the degree to which the dorsolateral prefrontal cortex was activated and its interconnection with the parietal cortex. In other words, your working memory capacity is determined by both storage capacity (in the posterior parietal cortex) and prefrontal top-down control. The findings may help in the development of ways to improve working memory capacity, particularly when working memory is damaged.
The results were published in the April 21 issue of Proceedings of the National Academy of Sciences.  Full reference
http://www.eurekalert.org/pub_releases/2009-04/i-id-aot040109.php

Some short-term memories die suddenly, no fading

We don’t remember everything; the idea of memory as being a video faithfully recording every aspect of everything we have ever experienced is a myth. Every day we look at the world and hold a lot of what we say for no more than a few seconds before discarding it as not needed any more. Until now it was thought that these fleeting visual memories faded away, gradually becoming more imprecise. Now it seems that such memories remain quite accurate as long as they exist (about 4 seconds), and then just vanish away instantly. The study involved testing memory for shapes and colors in 12 adults, and it was found that the memory for shape or color was either there or not there – the answers either correct or random guesses. The probability of remembering correctly decreased between 4 and 10 seconds.
The study was published in the April issue of Psychological Science.  Full reference
http://www.eurekalert.org/pub_releases/2009-04/uoc--ssm042809.php

Meditation technique can temporarily improve visuospatial abilities

And continuing on the subject of visual short-term memory, a study involving experienced practitioners of two styles of meditation: Deity Yoga (DY) and Open Presence (OP) has found that, although meditators performed similarly to nonmeditators on two types of visuospatial tasks (mental rotation and visual memory), when they did the tasks immediately after meditating for 20 minutes (while the nonmeditators rested or did something else), practitioners of the DY style of meditation showed a dramatic improvement compared to OP practitioners and controls. In other words, although the claim that regular meditation practice can increase your short-term memory capacity was not confirmed, it does appear that some forms of meditation can temporarily (and dramatically) improve it. Since the form of meditation that had this effect was one that emphasises visual imagery, it does support the idea that you can improve your imagery and visual memory skills (even if you do need to ‘warm up’ before the improvement is evident).
The study appeared in the May issue of Psychological Science.  Full reference
http://www.sciencedaily.com/releases/2009/04/090427131315.htm
http://www.eurekalert.org/pub_releases/2009-04/afps-ssb042709.php 

July 2008

Attention grabbers snatch lion's share of visual memory

It’s long been thought that when we look at a visually "busy" scene, we are only able to store a very limited number of objects in our visual short-term or working memory. For some time, this figure was believed to be four or five objects, but a recent report suggested it could be as low as two. However, a new study reveals that although it might not be large, it’s more flexible than we thought. Rather than being restricted to a limited number of objects, it can be shared out across the whole image, with more memory allocated for objects of interest and less for background detail. What’s of interest might be something we’ve previously decided on (i.e., we’re searching for), or something that grabs our attention.  Eye movements also reveal how brief our visual memory is, and that what our eyes are looking at isn’t necessarily what we’re ‘seeing’ — when people were asked to look at objects in a particular sequence, but the final object disappeared before their eyes moved on to it, it was found that the observers could more accurately recall the location of the object that they were about to look at than the one that they had just been looking at.
The study was published online 8 August in Science.  Full reference
http://www.physorg.com/news137337380.html

Even toddlers can ‘chunk' information for better remembering

We all know it’s easier to remember a long number (say a phone number) when it’s broken into chunks. Now a study has found that we don’t need to be taught this; it appears to come naturally to us. The study showed 14 months old children could track only three hidden objects at once, in the absence of any grouping cues, demonstrating the standard limit of working memory. However, with categorical or spatial cues, the children could remember more. For example, when four toys consisted of two groups of two familiar objects, cats and cars, or when six identical orange balls were grouped in three groups of two.
The research appeared online July 14 in the Proceedings of the National Academy of Sciences.  Full reference
http://www.eurekalert.org/pub_releases/2008-07/jhu-etg071008.php

Full text available at http://www.pnas.org/content/105/29/9926.abstract?sid=c01302b6-cd8e-4072-842c-7c6fcd40706f

April 2008

Working memory has a fixed number of 'slots'

A study that showed volunteers a pattern of colored squares for a tenth of a second, and then asked them to recall the color of one of the squares by clicking on a color wheel, has found that working memory acts like a high-resolution camera, retaining three or four features in high detail. Unlike a digital camera, however, it appears that you can’t increase the number of images you can store by lowering the resolution. The resolution appears to be constant for a given individual. However, individuals do differ in the resolution of each feature and the number of features that can be stored.
The paper was published online April 2 inl Nature.  Full reference
http://www.physorg.com/news126432902.html
http://www.eurekalert.org/pub_releases/2008-04/uoc--wmh040208.php

And another study of working memory has attempted to overcome the difficulties involved in measuring a person’s working memory capacity (ensuring that no ‘chunking’ of information takes place), and concluded that people do indeed have a fixed number of ‘slots’ in their working memory. In the study, participants were shown two, five or eight small, scattered, different-colored squares in an array, which was then replaced by an array of the same squares without the colors, after which the participant was shown a single color in one location and asked to indicate whether the color in that spot had changed from the original array.
The study was published in the April 22 issue of Proceedings of the National Academy of Sciences.  Full reference
http://www.eurekalert.org/pub_releases/2008-04/uom-mpd042308.php

February 2008

Children's under-achievement could be down to poor working memory

A survey of over three thousand children has found that 10% of school children across all age ranges suffer from poor working memory seriously affecting their learning. However, poor working memory is rarely identified by teachers, who often describe children with this problem as inattentive or as having lower levels of intelligence. The researchers have developed a new tool, a combination of a checklist and computer programme called the Working Memory Rating Scale, that enables teachers to identify and assess children's memory capacity in the classroom from as early as four years old. The tool has already been piloted successfully in 35 schools across the UK, and is now widely available. It has been translated into ten foreign languages.
http://www.physorg.com/news123404466.html 
http://www.eurekalert.org/pub_releases/2008-02/du-cuc022608.php

June 2006

Why are uniforms uniform? Because color helps us track objects

Laboratory tests have revealed that humans can pay attention to only 3 objects at a time. Yet there are instances in the real world — for example, in watching a soccer match — when we certainly think we are paying attention to more than 3 objects. Are we wrong? No. Anew study shows how we do it — it’s all in the color coding. People can focus on more than three items at a time if those items share a common color. But, logically enough, no more than 3 color sets.
The study was reported in the July issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2006-06/jhu-wau062106.htm

People remember prices more easily if they have fewer syllables

The phonological loop — an important component of working memory —can only hold 1.5 to 2 seconds of spoken information. For that reason, faster speakers have an advantage over slower speakers. Now a consumer study reveals that every extra syllable in a product's price decreases its chances of being remembered by 20%. Thus, people who shorten the number of syllables (e.g. read 5,325 as 'five three two five' as opposed to 'five thousand three hundred and twenty five') have better recall. However, since we store information both verbally and visually, it’s also the case that unusual looking prices, such as $8.88, are recalled better than typical looking prices.
The study will appear in the September issue of the Journal of Consumer Research. Full reference
http://www.sciencedaily.com/releases/2006/06/060623001231.htm
http://www.eurekalert.org/pub_releases/2006-06/uocp-prp062206.htm

November 2005

Discovery disproves simple concept of memory as 'storage space'

The idea of memory “capacity” has become more and more eroded over the years, and now a new technique for measuring brainwaves seems to finally knock the idea on the head. Consistent with recent research suggesting that a crucial problem with aging is a growing inability to ignore distracting information, this new study shows that visual working memory depends on your ability to filter out irrelevant information. Individuals have long been characterized as having a “high” working memory capacity or a “low” one — the assumption has been that these people differ in their storage capacity. Now it seems it’s all about a neural mechanism that controls what information gets into awareness. People with high capacity have a much better ability to ignore irrelevant information.
The finding was published in the November 24 issue of Nature. Full reference
http://www.eurekalert.org/pub_releases/2005-11/uoo-dds111805.htm

March 2005

How much can your mind keep track of?

A recent study has tried a new take on measuring how much a person can keep track of. It's difficult to measure the limits of processing capacity because most people automatically break down large complex problems into small, manageable chunks. To keep people from doing this, therefore, researchers created problems the test subjects wouldn’t be familiar with. 30 academics were presented with incomplete verbal descriptions of statistical interactions between fictitious variables, with an accompanying set of graphs that represented the interactions. It was found that, as the problems got more complex, participants performed less well and were less confident. They were significantly less able to accurately solve the problems involving four-way interactions than the ones involving three-way interactions, and were completely incapable of solving problems with five-way interactions. The researchers concluded that we cannot process more than four variables at a time (and at that, four is a strain).
The report was published in the January 2005 issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2005-03/aps-hmc030805.htm

August 2004

Tests for working memory capacity more limited than thought

The so-called “magic number 7” has been a useful mnemonic for working memory capacity — how many items you can hold in your working memory at one time — but we’ve known for some time that it isn’t quite as it was originally thought. Apart from the fact that the “7” is an average, and that the idea of an “item” is awfully vague as far as informational content is concerned, we have known for some time that what is really important is how long it takes for you to say the words. Thus, Chinese can hold on average 9 items, because the words used in the test are short and simple to pronounce, whereas the Welsh can hold only 5 on average, because of the length and complexity of their words. (note: it’s not because we actually say these words out loud). Similarly, the finding that deaf users of American Sign Language have an average of only 5 items was thought to be because signs take longer to utter. However, new research casts doubt on this theory. The researchers were trying to devise a sign-language test that would be comparable to a hearing language test. To their surprise they found that even when signs were faster to pronounce than spoken language, signers recalled only five items. Also, hearing individuals who were fluent in American Sign Language scored differently when asked to recall spoken lists in order, versus when they recalled signed lists (seven heard items remembered, five signed items remembered). Up until this time, the predominant idea was that the number found by this test was a good measure of overall cognitive capacity, but this assumption must now be in doubt. It's suggested that a test requiring recall of items, but not in temporal order, is a better measure of cognitive capacity. The results have important implications for standardized tests, which often employ ordered-list retention as a measure of a person's mental aptitude.
The report appeared as the cover story of the 15 August issue of Nature Neuroscience. Full reference
http://www.eurekalert.org/pub_releases/2004-08/uor-stm083104.htm

increasing working memory capacity

August 2009

Music training helps you hear better in noisy rooms

I’ve often talked about the benefits of musical training for cognition, but here’s a totally new benefit. A study involving 31 younger adults (19-32) with normal hearing has found that musicians (at least 10 years of music experience; music training before age 7; practicing more than 3 times weekly within previous 3 years) were significantly better at hearing and repeating sentences in increasingly noisy conditions, than the non-musicians. The number of years of music practice also correlated positively with better working memory and better tone discrimination ability. Hearing speech in noisy environments is of course difficult for everyone, but particularly for older adults, who are likely to have hearing and memory loss, and for poor readers.
The findings were published online 3 September in Ear and Hearing. Full reference
http://www.eurekalert.org/pub_releases/2009-08/nu-tum081709.php

April 2008

Brain-training to improve working memory boosts fluid intelligence

General intelligence is often separated into "fluid" and "crystalline" components, of which fluid intelligence is considered more reflective of “pure” intelligence (for more on this, see my article at http://www.memory-key.com/NatureofMemory/wm_iq.htm ), and largely resistant to training and learning effects. However, in a new study in which participants were given a series of training exercises designed to improve their working memory, fluid intelligence was found to have significantly improved, with the amount of improvement increasing with time spent training. The small study contradicts decades of research showing that improving on one kind of cognitive task does not improve performance on other kinds, so has been regarded with some skepticism by other researchers. More research is definitely needed, but the memory task did differ from previous studies, engaging executive functions such as those that inhibit irrelevant items, monitor performance, manage two tasks simultaneously, and update memory.
The research was published online April 28 ahead of print in the Proceedings of the National Academy of Sciences (PNAS).  Full reference
http://www.physorg.com/news128699895.html
http://www.sciam.com/article.cfm?id=study-shows-brain-power-can-be-bolstered

June 2005

Cognitive therapy for ADHD

A researcher that has previously demonstrated that working memory capacity can be increased through training, has now reported that the training software has produced significant improvement in children with ADHD — a disability that is associated with deficits in working memory. The study involved 53 children with ADHD, aged 7-12, who were not on medication for their disability. 44 of these met the criterion of more than 20 days of training. Half the participants were assigned to the working memory training program and the other half to a comparison program. 60% of those who underwent the wm training program no longer met the clinical criteria for ADHD after five weeks of training. The children were tested on visual-spatial memory, which has the strongest link to inattention and ADHD. Further research is needed to show that training improves ability on a wider range of tasks.
The study appeared in the February issue of the Journal of the American Academy of Child & Adolescent Psychiatry.
Full reference
http://www.sciam.com/article.cfm?articleID=000560D5-7252-12B9-9A2C83414B7F0000&sc=I100322

January 2004

Training improves working memory capacity

Working memory capacity has traditionally been thought to be constant. Recent studies, however, suggest that working memory can be improved by training. In this recent imaging study, it was found that adults who practiced working memory tasks for 5 weeks showed increased brain activity in the middle frontal gyrus and superior and inferior parietal cortices. These changes could be evidence of training-induced plasticity in the neural systems that underlie working memory.
The study was reported online on 14 December 2003 in Nature Neuroscience. Full reference
http://www.nature.com/cgi-taf/DynaPage.taf?file=/neuro/journal/v7/n1/abs/nn1165.html

November 2001

Gesturing reduces cognitive load

Why is it that people cannot keep their hands still when they talk? One reason may be that gesturing actually lightens cognitive load while a person is thinking of what to say. Adults and children were asked to remember a list of letters or words while explaining how they solved a math problem. Both groups remembered significantly more items when they gestured during their math explanations than when they did not gesture.
The report appeared in Psychological Science. Full reference
http://www.blackwellpublishers.co.uk/asp/journal.asp?ref=0956-7976&src=ard&aid=395&iid=6&vid=12

Factors that affect working memory

January 2010

Cultural differences & developmental changes in working memory

‘Working memory’ is thought to consist of three components: one concerned with auditory-verbal processing, one with visual-spatial processing, and a central executive that controls both. It has been hypothesized that the relationships between the components changes as children develop. Very young children are more reliant on visuospatial processing, but later the auditory-verbal module becomes more dominant. It has also been found that the two sensory modules are not strongly associated in younger (5-8) American children, but are strongly associated in older children (9-12). The same study found that this pattern was also found in Laotian children, but not in children from the Congo, none of whom showed a strong association between visual and auditory working memory. Now a new study has found that Ugandan children showed greater dominance of the auditory-verbal module, particularly among the older children (8 ½ +); however, the visuospatial module was dominant among Senegalese children, both younger and older. It is hypothesized that the cultural differences are a product of literacy training — school enrolment was much less consistent among the Senegalese. But there may also be a link to nutritional status.
The report appeared in the open-access journal PLoS ONE.    Full reference
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0008914

August 2009

Binge drinking affects attention and working memory in young university students

A Spanish study of 95 first-year university students, 42 of them binge drinkers, has found that those who engaged in binge drinking required greater attentional processing during a visual working memory task in order to carry it out correctly. They also had difficulties differentiating between relevant and irrelevant stimuli. Binge drinkers are defined as males who drink five or more standard alcohol drinks, and females who drink four or more, on one occasion and within a two-hour interval. Some 40% of university students in the U.S. are considered binge drinkers.
Results were published online August 10, and will appear in the November issue of Alcoholism: Clinical and Experimental Research. Full reference
http://www.eurekalert.org/pub_releases/2009-08/ace-bda080509.php

July 2009

Short stressful events may improve working memory

We know that chronic stress has a detrimental effect on learning and memory, but a new rat study shows how acute stress (a short, sharp event) can produce a beneficial effect. The rats, trained to a level of 60-70% accuracy on a maze, were put through a 20-minute forced swim before being run through the maze again. Those who experienced this stressful event were better at running the maze 4 hours later, and a day later, than those not forced through the stressful event. It appears that the stress hormone corticosterone (cortisol in humans) increases transmission of the neurotransmitter glutamate in the prefrontal cortex and improves working memory. It also appears that chronic stress suppresses the transmission of glutamate in the prefrontal cortex of male rodents, while estrogen receptors in female rodents make them more resilient to chronic stress than male rats.
The study appeared online July 29 in Proceedings of the National Academy of Sciences.  Full reference
http://www.eurekalert.org/pub_releases/2009-07/uab-sse072309.php

March 2009

When emotions involved, older adults may perform memory tasks better than young adults

A study involving 72 young adults (20-30 years old) and 72 older adults (60-75) has found that regulating emotions – such as reducing negative emotions or inhibiting unwanted thoughts – is a resource-demanding process that disrupts the ability of young adults to simultaneously or subsequently perform tasks, but doesn’t affect older adults. In the study, most of the participants watched a two-minute video designed to induce disgust, while the rest watched a neutral two-minute clip. Participants then played a computer memory game. Before playing 2 further memory games, those who had watched the disgusting video were instructed either to change their negative reaction into positive feelings as quickly as possible or to maintain the intensity of their negative reaction, or given no instructions. Those young adults who had been told to turn their disgust into positive feelings, performed significantly worse on the subsequent memory tasks, but older adults were not affected. The feelings of disgust in themselves did not affect performance in either group. It’s speculated that older adults’ greater experience allows them to regulate their emotions without cognitive effort.
The study was published in the March issue of Psychology and Aging. Full reference
http://www.eurekalert.org/pub_releases/2009-03/giot-oac030409.php

Inconsistent processing speed among children with ADHD

A new analytical technique has revealed that the problem with children with ADHD is not so much that they are slower at responding to tasks, but rather that their response is inconsistent. The study of 25 children with ADHD and 24 typically developing peers found that on a task in which a number on one screen needed to be mentally added to another number shown on a second screen, those with ADHD were much less consistent in their response times, although the responses they did give were just as accurate. Higher levels of hyperactivity and restlessness or impulsivity (as measured by parent survey) correlated with more slower reaction times. The finding supports the idea that what underlies impaired working memory is a problem in how consistently a child with ADHD can respond during a working memory task.
The study was published online 2 February in Child Neuropsychology.  Full reference
http://www.eurekalert.org/pub_releases/2009-03/uoc--ips032409.php

Hyperactivity enables children with ADHD to stay alert

A study of 12 8- to 12-year-old boys with ADHD, and 11 of those without, has found that activity levels of those with ADHD increased significantly whenever they had to perform a task that placed demands on their working memory. In a highly stimulating environment where little working memory is required (such as watching a Star Wars video), those with ADHD kept just as still as their normal peers. It’s suggested that movement helps them stay alert enough to complete challenging tasks, and therefore trying to limit their activity (when non-destructive) is counterproductive. Providing written instructions, simplifying multi-step directions, and using poster checklists are all strategies that can be used to help children with ADHD learn without overwhelming their working memories.
The findings were published in the May issue of Journal of Abnormal Child Psychology.  Full reference
http://www.eurekalert.org/pub_releases/2009-03/uocf-ush030909.php

Poverty can physically impair brain, reducing children's ability to learn

We know that stress affects learning and memory, and there is considerable evidence confirming the commonsense intuition that low-income families are under a lot of stress. Now a long-term study involving 195 children from rural households above and below the poverty line has found that children who lived in impoverished environments for longer periods of time during childhood showed higher stress scores and suffered greater impairments in working memory at 17. Those who spent their entire childhood in poverty scored about 20% lower on working memory tests at 17 than those who were never poor.
The study was published online March 30 in the Proceedings of the National Academy of Sciences. Full reference
Full text available at http://www.pnas.org/content/early/2009/03/27/0811910106.abstract?sid=b4c74b57-a4a5-447b-8675-ba75e69f3ec2
http://www.physorg.com/news158594009.html
http://www.washingtonpost.com/wp-dyn/content/article/2009/04/05/AR2009040501719.html

March 2007

New research shows why too much memory may be a bad thing

People who are able to easily and accurately recall historical dates or long-ago events may have a harder time with word recall or remembering the day's current events. A mouse study reveals why. Neurogenesis has been thought of as a wholly good thing — having more neurons is surely a good thing — but now a mouse study has found that stopping neurogenesis in the hippocampus improved working memory. Working memory is highly sensitive to interference from information previously stored in memory, so it may be that having too much information may hinder performing everyday working memory tasks.
The findings were published in the March 13 issue of the Proceedings of the National Academy of Sciences. Full reference
Full text is available at http://www.pnas.org/cgi/reprint/104/11/4642
http://www.physorg.com/news94384934.html
http://www.sciencedaily.com/releases/2007/03/070329092022.htm
http://www.eurekalert.org/pub_releases/2007-03/cumc-nrs032807.htm

February 2007

Implicit stereotypes and gender identification may affect female math performance

Another study has come out showing that women enrolled in an introductory calculus course who possessed strong implicit gender stereotypes, (for example, automatically associating "male" more than "female" with math ability and math professions) and were likely to identify themselves as feminine, performed worse relative to their female counterparts who did not possess such stereotypes and who were less likely to identify with traditionally female characteristics. Strikingly, a majority of the women participating in the study explicitly expressed disagreement with the idea that men have superior math ability, suggesting that even when consciously disavowing stereotypes, female math students are still susceptible to negative perceptions of their ability.
The article was published in the January issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2007-01/afps-isa012407.htm

February 2007

Reducing the racial achievement gap

And staying with the same theme, a study that came out six months ago, and recently reviewed on the excellent new Scientific American Mind Matters blog, revealed that a single, 15-minute intervention erased almost half the racial achievement gap between African American and white students. The intervention involved writing a brief paragraph about which value, from a list of values, was most important to them and why. The intervention improved subsequent academic performance for some 70% of the African American students, but none of the Caucasians. The study was repeated the following year with the same results. It is thought that the effect of the intervention was to protect against the negative stereotypes regarding the intelligence and academic capabilities of African Americans.
The research appeared in the September 1 issue of Science. Full reference
http://blog.sciam.com/index.htm?title=closing_the_racial_achievement_gap&more=1&c=1&tb=1&pb=1

Highly accomplished people more prone to failure than others when under stress

One important difference between those who do well academically and those who don’t is often working memory capacity. Those with a high working memory capacity find it easier to read and understand and reason, than those with a smaller capacity. However, a new study suggests there is a downside. Such people tend to heavily rely on their abundant supply of working memory and are therefore disadvantaged when challenged to solve difficult problems, such as mathematical ones, under pressure — because the distraction caused by stress consumes their working memory. They then fall back on the less accurate short-cuts that people with less adequate supplies of working memory tend to use, such as guessing and estimation. Such methods are not made any worse by working under pressure. In the study involving 100 undergraduates, performance of students with strong working memory declined to the same level as those with more limited working memory, when the students were put under pressure. Those with more limited working memory performed as well under added pressure as they did without the stress.
The findings were presented February 17 at the annual meeting of the American Association for the Advancement of Science.
http://www.eurekalert.org/pub_releases/2007-02/uoc-hap021607.htm

Common gene version optimizes thinking but carries a risk

On the same subject, another study has found that the most common version of DARPP-32, a gene that shapes and controls a circuit between the striatum and prefrontal cortex, optimizes information filtering by the prefrontal cortex, thus improving working memory capacity and executive control (and thus, intelligence). However, the same version was also more prevalent among people who developed schizophrenia, suggesting that a beneficial gene variant may translate into a disadvantage if the prefrontal cortex is impaired. In other words, one of the things that make humans more intelligent as a species may also make us more vulnerable to schizophrenia.
The study was published online February 8, and in the March 1 issue of the Journal of Clinical Investigation. Full reference
http://www.sciencedaily.com/releases/2007/02/070208230059.htm
http://www.eurekalert.org/pub_releases/2007-02/niom-cgv020707.htm

February 2005

Anxiety adversely affects those who are most likely to succeed at exams

It has been thought that pressure harms performance on cognitive skills such as mathematical problem-solving by reducing the working memory capacity available for skill execution. However, a new study of 93 students has found that this applies only to those high in working memory. It appears that the advantage of a high working memory capacity disappears when that attention capacity is compromised by anxiety.
The study was published in the February issue of Psychological Science. Full reference
http://www.eurekalert.org/pub_releases/2005-02/bpl-wup020705.htm

November 2003

Memory-enhancing drugs for elderly may impair working memory and other executive functions

Drugs that increase the activity of an enzyme called protein kinase A improve long-term memory in aged mice and have been proposed as memory-enhancing drugs for elderly humans. However, the type of memory improved by this activity occurs principally in the hippocampus. A new study suggests that increased activity of this enzyme has a deleterious effect on working memory (which principally involves the prefrontal cortex). In other words, a drug that helps you remember a recent event may worsen your ability to remember what you’re about to do (to take an example).
The research was published in the November 13 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2003-11/naos-mdf110303.htm

Sleep deprivation affects working memory

A recent study investigated the working memory capacities of individuals who were sleep-deprived. For nine days, 7 of the 12 participants slept four hours each night, and 5 slept for eight hours. Each morning, participants completed a computer task to measure how quickly they could access a list of numbers they had been asked to memorize. The list could be one, three, or five items long. Then participants were presented with a series of single digits and asked to answer "yes" or "no" to indicate whether each digit was one they had memorized. Those who slept eight hours a night steadily increased their working memory efficiency on this task, but those who slept only four hours a night failed to show any improvement in memory efficiency. Motor skill did not change across days for either group of participants.
http://www.eurekalert.org/pub_releases/2003-11/sfn-sfb_1111003.htm

The neural substrate of working memory

November 2009

More light shed on distinction between long and short-term memory

The once clear-cut distinction between long- and short-term memory has increasingly come under fire in recent years. A new study involving patients with a specific form of epilepsy called 'temporal lobe epilepsy with bilateral hippocampal sclerosis' has now clarified the distinction. The patients, who all had severely compromised hippocampi, were asked to try and memorize photographic images depicting normal scenes. Their memory was tested and brain activity recorded after five seconds or 60 minutes. As expected, the patients could not remember the images after 60 minutes, but could distinguish seen-before images from new at five seconds. However, their memory was poor when asked to recall details about the images. Brain activity showed that short-term memory for details required the coordinated activity of a network of visual and temporal brain areas, whereas standard short-term memory drew on a different network, involving frontal and parietal regions, and independent of the hippocampus.
The report was published in the December 1 issue of Proceedings of the National Academy of Sciences.   Full reference
http://www.eurekalert.org/pub_releases/2009-11/ucl-tal110909.php

April 2009

Individual differences in working memory capacity depend on two factors

A new computer model adds to our understanding of working memory, by showing that working memory can be increased by the action of the prefrontal cortex in reinforcing activity in the parietal cortex (where the information is temporarily stored). The idea is that the prefrontal cortex sends out a brief stimulus to the parietal cortex that generates a reverberating activation in a small subpopulation of neurons, while inhibitory interactions with neurons further away prevents activation of the entire network. This lateral inhibition is also responsible for limiting the mnemonic capacity of the parietal network (i.e. provides the limit on your working memory capacity). The model has received confirmatory evidence from an imaging study involving 25 volunteers. It was found that individual differences in performance on a short-term visual memory task were correlated with the degree to which the dorsolateral prefrontal cortex was activated and its interconnection with the parietal cortex. In other words, your working memory capacity is determined by both storage capacity (in the posterior parietal cortex) and prefrontal top-down control. The findings may help in the development of ways to improve working memory capacity, particularly when working memory is damaged.
The results were published in the April 21 issue of Proceedings of the National Academy of Sciences.  Full reference
http://www.eurekalert.org/pub_releases/2009-04/i-id-aot040109.php

February 2009

Where visual short-term memory occurs

Working memory used to be thought of as a separate ‘store’, and now tends to be regarded more as a process, a state of mind. Such a conception suggests that it may occur in the same regions of the brain as long-term memory, but in a pattern of activity that is somehow different from LTM. However, there has been little evidence for that so far. Now a new study has found that information in WM may indeed be stored via sustained, but low, activity in sensory areas. The study involved volunteers being shown an image for one second and instructed to remember either the color or the orientation of the image. After then looking at a blank screen for 10 seconds, they were shown another image and asked whether it was the identical color/orientation as the first image. Brain activity in the primary visual cortex was scanned during the 10 second delay, revealing that areas normally involved in processing color and orientation were active during that time, and that the pattern only contained the targeted information (color or orientation).
The report appeared in the February issue of Psychological Science.  Full reference
http://www.eurekalert.org/pub_releases/2009-02/afps-sih022009.php
http://www.eurekalert.org/pub_releases/2009-02/uoo-dsm022009.php

The finding is consistent with that of another study published this month, in which participants were shown two examples of simple striped patterns at different orientations and told to hold either one or the other of the orientations in their mind while being scanned. Orientation is one of the first and most basic pieces of visual information coded and processed by the brain. Using a new decoding technique, researchers were able to predict with 80% accuracy which of the two orientations was being remembered 11 seconds after seeing a stimulus, from the activity patterns in the visual areas. This was true even when the overall level of activity in these visual areas was very weak, no different than looking at a blank screen.
The results of this study were published online February 18 in Nature.  Full reference
http://www.eurekalert.org/pub_releases/2009-02/vu-edi021709.php
http://www.physorg.com/news154186809.html

May 2006

New view of hippocampus’s role in memory

Amnesiacs have overturned the established view of the hippocampus, and of the difference between long-and short-term memories. It appears the hippocampus is just as important for retrieving certain types of short-term memories as it is for long-term memories. The critical thing is not the age of the memory, but the requirement to form connections between pieces of information to create a coherent episode. The researchers suggest that, for the brain, the distinction between 'long-term' memory and 'short-term' memory are less relevant than that between ‘feature’ memory and ‘conjunction’ memory — the ability to remember specific things versus how they are related. The hippocampus may be thought of as the brain's switchboard, piecing individual bits of information together in context.
The findings were published in the April issue of the Journal of Neuroscience. Full reference
http://origin.www.upenn.edu/pennnews/article.htm?id=963
http://www.eurekalert.org/pub_releases/2006-05/uop-aso053106.htm

October 2004

Development of working memory with age

An imaging study of 20 healthy 8- to 30-year-olds has shed new light on the development of working memory. The study found that pre-adolescent children relied most heavily on the prefrontal and parietal regions of the brain during the working memory task; adolescents used those regions plus the anterior cingulate; and in adults, a third area of the brain, the medial temporal lobe, was brought in to support the functions of the other areas. Adults performed best. The results support the view that a person's ability to have voluntary control over behavior improves with age because with development, additional brain processes are used.
http://www.eurekalert.org/pub_releases/2004-10/uopm-dow102104.htm

May 2004

Hippocampus and subiculum both critical for short-term memory

A new animal study has revealed that the hippocampus shares its involvement in short-term memory with an adjacent brain region, the subiculum. Both regions act together to establish and retrieve short-term memories. The process involves each region acting at different times, with the other region shutting off while the other is active. The shortest memories (10-15s) were found to be controlled almost exclusively by the subiculum. After 15s, the hippocampus took over. It was also found that the hippocampus appeared to respond in a way influenced by previous experiences, allowing it to anticipate future events on the basis of past outcomes. This is an advantage but can also cause errors.
The research was reported in the May 13 issue of Neuron. Full reference
http://www.eurekalert.org/pub_releases/2004-05/wfub-nrs050604.htm

Small world networks key to working memory

A computer model may reveal an important aspect of working memory. The key, researchers say, is that the neurons form a "small world" network. In such a network, regardless of its size, any two points within them are always linked by only a small number of steps. Working memory may rely on the same property.
http://www.newscientist.com/news/news.jsp?id=ns99995012

April 2004

Why working memory capacity is so limited

There’s an old parlor game whereby someone brings into a room a tray covered with a number of different small objects, which they show to the people in the room for one minute, before whisking it away again. The participants are then required to write down as many objects as they can remember. For those who perform badly at this type of thing, some consolation from researchers: it’s not (entirely) your fault. We do actually have a very limited storage capacity for visual short-term memory.
Now visual short-term memory is of course vital for a number of functions, and reflecting this, there is an extensive network of brain structures supporting this type of memory. However, a new imaging study suggests that the limited storage capacity is due mainly to just one of these regions: the posterior parietal cortex. An interesting distinction can be made here between registering information and actually “holding it in mind”. Activity in the posterior parietal cortex strongly correlated with the number of objects the subjects were able to remember, but only if the participants were asked to remember. In contrast, regions of the visual cortex in the occipital lobe responded differently to the number of objects even when participants were not asked to remember what they had seen.
The research was published in the April 15 edition of Nature. Full reference
http://www.eurekalert.org/pub_releases/2004-04/vu-slo040704.htm
http://tinyurl.com/2jzwe (Telegraph article)

Brain signal predicts working memory capacity

Our visual short-term memory may have an extremely limited capacity, but some people do have a greater capacity than others. A new study reveals that an individual's capacity for such visual working memory can be predicted by his or her brainwaves. In the study, participants briefly viewed a picture containing colored squares, followed by a one-second delay, and then a test picture. They pressed buttons to indicate whether the test picture was identical to -- or differed by one color -- from the one seen earlier. The more squares a subject could correctly identify having just seen, the greater his/her visual working memory capacity, and the higher the spike of corresponding brain activity – up to a point. Neural activity of subjects with poorer working memory scores leveled off early, showing little or no increase when the number of squares to remember increased from 2 to 4, while those with high capacity showed large increases. Subjects averaged 2.8 squares.
The study appeared in the April 15 issue of Nature. Full reference
http://www.eurekalert.org/pub_releases/2004-04/niom-bsp041604.htm
http://tinyurl.com/2jzwe (Telegraph article)