Problems

Older news items (pre-2010) brought over from the old website

Positive stereotypes can offset negative stereotype effect

A number of studies have now shown that negative stereotypes can impair cognitive performance, mainly through adding to working memory load. A new study has now shown that this effect can be mitigated by the activation of a positive stereotype. The research takes advantage of the fact that we all belong to several social groups. In this case, the relevant groups were ‘female’ and ‘college student’. As usual, when (subtly) reminded of negative stereotypes for women and math, women performed worse. The interesting thing was that this didn’t happen if women were also made aware that college students performed better at math than non-college students. Moreover, this was reflected in working memory capacity. It seems that, when both a positive and a negative stereotype are offered, people will tend to choose the positive stereotype, and the effects of this will cancel out the negative stereotype. It’s also worth noting how easily these stereotypes are activated: effects could be manipulated simply by subtly changing demographic questions asked before the test (and it is not uncommon that test-takers are first required to answer some demographic questions).

http://www.eurekalert.org/pub_releases/2009-05/iu-pob050109.php

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.

http://www.eurekalert.org/pub_releases/2007-01/afps-isa012407.php

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.

Women's math performance affected by theories on sex differences

In a salutary reminder to all researchers into gender and race differences, researchers found that women who received a genetic explanation for female underachievement in math or were reminded of the stereotype about female math underachievement, performed more poorly on math tests than those who received an experiential explanation (such as math teachers treating boys preferentially during the first years of math education) or were led to believe there are no sex differences in math.

http://www.eurekalert.org/pub_releases/2006-10/uobc-wmp101306.php

Interactions with other races can impair mental capacity in the strongly prejudiced

A new approach on an old theme — the effect of stress on cognitive function. The study looked at the short-term effects of racial prejudice. White college students were assessed for racial bias and then had a conversation with either a black or white person. After the conversation, they were given the Stroop test (participants are presented with color words, which are either in the same color as they name, or not; they are required to respond on the basis of the color of the word, not the name. The test requires a surprising amount of concentration.) For those who had talked with a black person, the greater the amount of racial bias, the worse the student did on the Stroop test. This is assumed to be due to the stress caused by the interaction.

http://www.eurekalert.org/pub_releases/2003-04/pu-tpo043003.php

Older news items (pre-2010) brought over from the old website

Scent of fear impacts cognitive performance

A study involving 75 female students found that those who were exposed to chemicals from fear-induced sweat performed more accurately on word-association tasks than did women exposed to chemicals from other types of sweat or no sweat at all. When processing meaningfully related word pairs, the participants exposed to the fear chemicals were significantly more accurate than those in either the neutral sweat or the control (no-sweat) condition. When processing word pairs that were ambiguous in threat content, such as one neutral word paired with a threatening word or a pair of neutral words, subjects in the fear condition were significantly slower in responding than those in the neutral sweat condition.

Chen, D., Katdare, A. & Lucas, N. 2006. Chemosignals of Fear Enhance Cognitive Performance in Humans. Chemical Senses, Advance Access published on March 9, 2006

http://www.eurekalert.org/pub_releases/2006-03/ru-sof033106.php

Memory of fear more complex than supposed

It seems that fear memory is more complex than has been thought. A new mouse study has shown that not only the hippocampus and amygdala are involved, but that the prefrontal cortex is also critical. The development of the fear association doesn’t occur immediately after a distressing event, but develops over time. The process, it now seems, depends directly on a protein called NR2B.

http://www.eurekalert.org/pub_releases/2005-09/uot-sco091505.php

How trauma triggers long-lasting memories in the brain

A rat study sheds more light on why emotional experiences tend to be better remembered than emotionally neutral events. The study found that emotionally arousing events activated the amygdala, which then increased a specific protein — activity-regulated cytoskeletal protein ("Arc") — in the neurons in the hippocampus. It's thought that Arc helps store these memories by strengthening the synapses.

http://www.eurekalert.org/pub_releases/2005-07/uoc--nih072505.php

Why traumatic memories have the power they do

In the first imaging study to look at retrieval of emotional memories after a long period (one year after encoding), researchers found that people did recall emotional images, both pleasant and unpleasant, better than emotionally-neutral images. This recall was associated with higher activity in both the amygdala and the hippocampus. The synchronicity of activity between these two regions suggested that each region triggers the other, creating a self-reinforcing "memory loop" in which an emotional cue might trigger recall of the event, which then loops back to a re-experiencing of the emotion of the event. The findings suggest why people subject to traumatic events may be trapped in a cycle of emotion and recall that aggravates post-traumatic stress disorder, and may also suggest why therapies in which people relive such memories and reshape perspective to make it less traumatic can help people cope with such memories.

http://www.eurekalert.org/pub_releases/2005-03/du-ems030805.php

Reducing the trauma of traumatic memories

For some, stressful memories can reawaken intense fear, with undesirable consequences. A new study involving mice has found that such stress induces a change in the expression of the acetylcholinesterase gene, which normally produces a vital protein that adheres to neuronal synapses. Following stress, however, the same gene produces large quantities of a protein with modified properties that results in heightened electrical signals in the nerve cells communicating through these synapses. The effect is to create reactions of extreme fright or immobilizing shock. Later encounter with a context which triggers those stressful memories can set off that same neuronal reaction. The researchers have developed an "antisense" agent that acts to neutralize the process whereby the modified protein is produced, thereby preventing the extreme reaction.

http://www.eurekalert.org/pub_releases/2003-12/huoj-hug121103.php
http://www.eurekalert.org/pub_releases/2003-12/mp-abm120803.php

Older news items (pre-2010) brought over from the old website

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.

http://www.eurekalert.org/pub_releases/2009-07/uab-sse072309.php

Stressed brains rely on habit

And another rat study has found that rats stressed repeatedly and unpredictably for three weeks were more likely than unstressed animals to continue performing habitual behaviors, even when it no longer made sense to do so. This behavior was correlated with reductions in the prelimbic cortex of the medial prefrontal cortex and the dorsomedial striatum (both implicated in goal-directed actions), and increases in the size of the dorsolateral striatum (necessary for habit). The finding follows on from previous research showing that habit formation involves a switch between neural circuits associated with goal-directed behavior and those controlling habitual behavior. The findings have implications for therapies for stress-related disorders and addictive behavior.

http://www.the-scientist.com/blog/display/55873/

Stress disrupts task-switching, but the brain can bounce back

A new neuroimaging study involving 20 male M.D. candidates in the middle of preparing for their board exams has found that they had a harder time shifting their attention from one task to another after a month of stress than other healthy young men who were not under stress. The finding replicates what has been found in rat studies, and similarly correlates with impaired function in an area of the prefrontal cortex that is involved in attention. However, the brains recovered their function within a month of the end of the stressful period.

Full text available at http://www.pnas.org/content/106/3/912.abstract
http://www.eurekalert.org/pub_releases/2009-01/ru-sdh012709.php

Psychological distress, not depression, linked to increased risk of stroke

A study following 20,627 people for an average of 8.5 years has found that psychological distress was associated with an increased risk of stroke and that the risk of stroke increased the more distress the participants reported. This association remained the same regardless of cigarette smoking, systolic blood pressure, overall blood cholesterol, obesity, previous heart attack, diabetes, social class, education, high blood pressure treatment, family history of stroke and recent antidepressant medication use. However, there was no increased risk for people who had experienced an episode of major depression in the past year or at any point in their lifetime.

http://www.eurekalert.org/pub_releases/2008-03/aaon-pdn022608.php

Short-term stress can affect learning and memory

We know that long-lasting, severe stress can impair cell communication in the hippocampus. Now rodent studies have demonstrated that the same outcome can happen with short-term stress. But rather than involving the familiar stress hormone cortisol, acute stress activated corticotropin releasing hormones, which led to the rapid disintegration of dendritic spines in the hippocampus, thus limiting the ability of synapses to collect and store memories.

http://www.eurekalert.org/pub_releases/2008-03/uoc--ssc031008.php

Correct levels of stress hormones boost learning

Although it’s known that cortisol production is related to stress and has an impact on learning in humans, that impact is not well understood, because of the difficulties of controlling cortisol levels in humans. A study using ground squirrels has now found that they learn more quickly if they have a modest amount of cortisol, rather than either high or low levels of cortisol.

http://www.eurekalert.org/pub_releases/2008-03/uoc-rws031208.php

Stress hormone impacts memory, learning in diabetic rodents

A rodent study sheds light on why diabetes can impair cognitive function. The study found that increased levels of a stress hormone (called cortisol in humans) in diabetic rats impaired synaptic plasticity and reduced neurogenesis in the hippocampus. When levels returned to normal, the hippocampus recovered. Cortisol production is controlled by the hypothalamic-pituitary axis (HPA). People with poorly controlled diabetes often have an overactive HPA axis and excessive cortisol.

http://www.eurekalert.org/pub_releases/2008-02/nioa-shi021508.php

How stress affects memory

We know stress affects memory. Now a rat study tells us one of the ways it does that. Cell recordings in the hippocampus revealed that, when a mouse moves from one location to another, particular cells fired at each location. When the mouse returned to an earlier location, the same cells fire. However, following stress, the cells that fired in a particular location still fired at the same location, but tended to fire at a different frequency. Stress also reduce the level of LTP at the synapses.

http://www.sciencentral.com/articles/view.php3?article_id=218393035

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.php

Lifestyle changes improve seniors’ memory surprisingly quickly

A small 14-day study found that those following a memory improvement plan that included memory training, a healthy diet, physical exercise, and stress reduction, showed a 5% decrease in brain metabolism in the dorsal lateral prefrontal region of the brain (involved in working memory) suggesting they were using their brain more efficiently. This change in activity was reflected in better performance on a cognitive measure controlled by this brain region, and participants reported that they felt their memory had improved. The memory training involved doing brainteasers, crossword puzzles and memory exercises. Diet involved eating 5 small meals daily (to prevent fluctuations in blood glucose levels) that were rich in omega-3 fats, low-glycemic index carbohydrates (e.g., whole grains) and antioxidants. Physical exercise involved brisk walking and stretching, and stress reduction involved stretching and relaxation exercises.

The study was presented at the American College of Neuropsychopharmacology's Annual Meeting on December 11-15, in Hawaii.

http://www.eurekalert.org/pub_releases/2005-12/g-nsf121205.php

Stress interferes with problem-solving; Beta-blocker may help

New research suggests that an experience as simple as watching graphically violent or emotional scenes in a movie can induce enough stress to interfere with problem-solving abilities, and that a beta-blocker medication could promote the ability to think flexibly under stressful conditions. Neither the stress nor the beta-blocker affected memory. The research not only has implications for understanding the range of effects of stress on thinking, but could also have broader clinical implications for patients with anxiety disorders or substance abuse problems.

Renner, K., Alexander, J., Hillier, A., Smith, R. & Tivarus, M. 2005. Presented at the annual Society for Neuroscience meeting in Washington, D.C.

http://www.eurekalert.org/pub_releases/2005-11/osu-siw110905.php

Early life stress can lead to memory loss and cognitive decline in middle age

Age-related cognitive decline is probably a result of both genetic and environmental factors. A rat study has demonstrated that some of these environmental factors may occur in early life. Among the rats, emotional stress in infancy showed no ill effects by the time the rats reached adulthood, but as the rats reached middle age, cognitive deficits started to appear in those rats who had had stressful infancies, and progressed much more rapidly with age than among those who had had nurturing infancies. Middle-aged rats who had been exposed to early life emotional stress showed deterioration in brain-cell communication in the hippocampus.

http://www.eurekalert.org/pub_releases/2005-10/uoc--els100605.php

Stress bad for the brain

A study of older adults for three to six years has found that those with continuous high levels of the stress hormone cortisol performed poorly on memory tests and had a 14% smaller hippocampus. A further study involving young adults and children between the ages of six and fourteen found that even an acute increase in cortisol can lead to reversible memory impairments in young adults, and that children from low socio-economic status environments had higher cortisol levels than those from high SES homes. Children from low SES homes tended to process positive and negative attributes more negatively than children from high SES homes, and this type of processing was significantly related to basal cortisol levels at ages 10, 12 and 14.

http://www.eurekalert.org/pub_releases/2005-05/mu-tst051705.php

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.

http://www.eurekalert.org/pub_releases/2005-02/bpl-wup020705.php

Anxiety good for memory recall, bad for solving complex problems

Cognitive tests given to 19 first-year medical students one to two days before a regular classroom exam, and then a week after the exam, found that, before the exam, students were better able to accurately recall a list of memorized numbers, but did less well on tests that required them to consider many possibilities in order to come up with a reasonable answer. A week after the exam, the opposite was true. It is assumed that the difference in results reflects the effects of stress.

Jessa Alexander & David Beversdorf presented their findings on October 25 in San Diego at the annual Society for Neuroscience conference.

http://www.eurekalert.org/pub_releases/2004-10/osu-agf101904.php

Estrogen effect on memory influenced by stress

The question of whether estrogen helps memory and cognition in women has proven surprisingly difficult to answer, with studies giving conflicting results. Now it seems the answer to that confusion is: it depends. And one of the things it depends on may be the level of stress the woman is experiencing. A rat study has found that the performance of female rats in a water maze was affected by the interaction of hormone level (whether the rat was estrous or proestrous) with water temperature (a source of physical stress). Those rats with high hormone levels did better when the water was warm, while those with low hormone levels did better when the water was cold. The researchers suggest both timing and duration of stress might be factors in determining the effect of hormones on cognition.

http://www.eurekalert.org/pub_releases/2004-08/uoia-sss082704.php

Stress reactions no guarantee of authenticity

Physical stress reactions have often been taken as evidence for the authenticity of a memory. A recent study investigated people with “memories” of alien abductions (on the grounds that these are the memories least likely to be true) and found that those who believed they had been abducted by aliens responded physically to recall of that memory in the same way as to recall of other, true, stressful events. The finding suggests that a person’s reaction to a memory is no evidence for whether or not it truly happened.

http://www.eurekalert.org/pub_releases/2004-06/aps-ptw062104.php

Stress no aid to memory

Numerous studies have questioned the accuracy of recall of traumatic events, but the research is often dismissed as artificial and not intense enough to simulate real-life trauma. A new study has used real stress: 509 active duty military personnel enrolled in survival school training were deprived of food and sleep 48 hours and then interrogated. A day later, only 30% of those presented with a line-up could identify the right person, only 34% identified their interrogator from a photo-spread and 49% from single photos shown sequentially (putting the interrogator in the same clothing boosted correct identification to 66%). Thirty people even got the gender wrong. Those subjected to physical threats (half the participants) performed worse.

http://www.newscientist.com/news/news.jsp?id=ns99995089
http://www.eurekalert.org/pub_releases/2004-06/yu-emp060304.php
http://www.eurekalert.org/pub_releases/2004-06/ns-mfy060904.php

Anxiety over math blocks learning

The so-called "math block" is notorious - why do we have such a term? Do we talk about a "geography block", or a "physics block"? But we do talk of a reading block. Perhaps the reason for both is the same.
The amount of information you can work with at one time has clear limits, defined by your working memory capacity. When we are anxious, part of our working memory is taken up with our awareness of these fears and worries, leaving less capacity available for processing (which is why students who are very anxious during exams usually perform well below their capabilities). Processes such as reading and working with numbers are very sensitive to working memory capacity because they place such demands on it.
A recently reported study by Mark H. Ashcraft and Elizabeth P. Kirk, both psychologists at Cleveland (Ohio) State University, provides the first solid evidence that, indeed, math-anxious people have working memory problems as they do math.

http://www.sciencenews.org/20010630/fob4.asp