Attention Problems

Latest Research News

A study involving 88 women, some of whom had endocrinological disorders, has found that, while some hormones were associated with changes across one menstrual cycle in some of the women taking part, these effects didn't repeat in the following cycle. In other words, there was no consistent effect of hormonal changes on cognition. This is not to say that some individuals might not be consistently affected, just that it doesn’t appear to be a general rule.

While the number of participants isn’t huge, it is considerably larger than is common in these sort of studies. The replication across two cycles is particularly important, since if the researchers had settled for just looking at one cycle, they would have concluded that there was an effect on cognition — as several studies have previously concluded. This more rigorous study suggests that earlier findings should be regarded with caution.

The study followed the women through two menstrual cycles. For the first cycle, 88 women participated; 68 women were re-assessed for a second cycle, to rule out practice effects and false-positive chance findings. Visuospatial working memory, attention, cognitive bias and hormone levels were assessed at four consecutive time-points across both cycles.

Of the initial 88, 58 had no endocrinological problems, 13 were diagnosed with endometriosis, 16 with polycystic ovary syndrome (PCOS) and one woman with hyperprolactinemia. Additionally, 12 women presented with obesity. Women were excluded if they were using oral contraceptives, had been pregnant or breastfeeding within the past 6 months, were using medication or had surgery which might interfere with endocrine parameters, had severe psychiatric or general diseases, worked irregular shifts, had menstrual or ovulation disorders except those investigated in the study, or showed any additional abnormality in hormonal parameters. Mean age was 30. Data from the subset of healthy women were also analyzed separately, confirming no difference in the findings. I would have liked the researchers to mention how the 68 women in the replication were selected, but I assume, after all their emphasis on methodological rigor, that they would have been careful to make sure there was no bias in that selection.

It should be noted, however, that the cognitive testing wasn’t exhaustive by any means — it’s possible that other cognitive aspects might be affected by hormonal changes. However, attention and working memory are the areas generally accused, and most likely to be noticed by an individual.

Of course, that’s the thing about attention and working memory — they’re very sensitive to a host of factors, including sleep quality and stress. So, we often notice that we’re not working at top gear, and we’re likely to look around for reasons. If we’re women, and it’s our period or just before it, we’re quite likely to attribute the reason to that. And it may be true in an indirect way — if we have pain, or sleeplessness, or are stressed, for example. What this study tells us, is that the changes in hormonal levels don't seem to consistently affect cognition.

https://www.eurekalert.org/pub_releases/2017-07/f-mdc062717.php

We've all done it: used the wrong name when we know the right one perfectly well. And we all know when it's most likely to happen. But here's a study come to reassure us that it's okay, this is just how we roll.

The study, based on five separate surveys of more than 1,700 respondents, finds that these naming errors (when you call someone you know very well by the wrong name) follow a particular pattern that tells us something about how our memory is organized.

Usually the wrong name comes from the same relationship category. So I call one son by the name of the other; on a bad day (e.g. when there's a lot going on, perhaps a lot of people around, and I'm thinking of many other things — say, at Christmas), I might run through both sons, my partner, and my father!

Not just family, you can mix up friends' names too. And the bit that's really enlightening: family members might also be called by the name of the family dog! Interestingly, only the dog; cat owners don't make such slips of the tongue. (Yes, dogs are family; cats not so much.)

Unsurprisingly, phonetic similarity between names is also a factor, although it's less important than relational category. Names with the same beginning or ending sounds, or with shared phonemes (e.g., John and Bob), are more likely to be muddled.

But it's not affected by physical similarity between people — not even by gender (which surprised me, but then, in my household I'm the only female).

More importantly, it's not a function of age. Misnaming errors are common across the board.

http://www.futurity.org/moms-families-dogs-names-1152392/

More than 10% of all babies are born preterm every year, and prematurity is a well-established risk factor for cognitive impairment at some level.

Prematurity affects working memory in particular

In a recent German study involving 1326 8-year-old children, it was found that being born preterm specifically affected the ability to solve tasks with a high cognitive load (i.e. greater demands on working memory), whereas tasks with a low load were largely unaffected.

These findings are consistent with other research suggesting that prematurity is associated in particular with difficulties in math, in complex problem-solving, and in simultaneous processing (such as occurs in recognition of spatial patterns).

There was also a clear dividing line, with deficits disproportionally higher for children born before the 34th week of pregnancy compared with children born after week 33.

Rate of cognitive impairment in premature infants

A Swedish study of 491 toddlers (2 ½ years) who had been born extremely preterm (less than 27 gestational weeks) found that 42% of them had no disability (compared with 78% of controls), 31% had mild disability, 16% had moderate disability, and 11% had severe disability. Unsurprisingly, there was an increase in moderate or severe disabilities with greater prematurity. There was no gender difference.

Cognitive impairment in premies linked to smaller brain tissue in specific regions

Why are some individuals affected by prematurity, why others aren’t? An analysis of brain imaging data of 97 adolescents who had very low birth weights, and whose academic progress has been followed, found that more than half of the babies that weighed less than 1.66 pounds and more than 30% of those less than 3.31 pounds at birth later had academic deficits. Academic deficits were linked to smaller brain volumes, and in particular to reduced volume of the caudate and corpus callosum, which are involved in connectivity, executive attention and motor control.

J. Jäkel, N. Baumann, D. Wolke (2013): Effects of gestational age at birth on cognitive performance: a function of cognitive workload demands, PLOS ONE, http://dx.plos.org/10.1371/journal.pone.0065219

[3444] Serenius F KK. Neurodevelopmental outcome in extremely preterm infants at 2.5 years after active perinatal care in sweden. JAMA [Internet]. 2013 ;309(17):1810 - 1820. Available from: http://dx.doi.org/10.1001/jama.2013.3786

[3442] Clark, C A, Fang H, Espy KA, Filipek PA, Juranek J, Bangert B, Hack M, Gerry H. Relation of neural structure to persistently low academic achievement: A longitudinal study of children with differing birth weights. Neuropsychology. 2013 ;27(3):364 - 377.

http://www.eurekalert.org/pub_releases/2013-05/rb-pba052713.php (1st study)

http://www.eurekalert.org/pub_releases/2013-04/tjnj-sen042513.php (2nd study)

http://www.eurekalert.org/pub_releases/2013-06/uoo-rbv061013.php (3rd study)

Why do we find it so hard to stay on task for long? A recent study uses a new technique to show how the task control network and the default mode network interact (and fight each other for control).

The task control network (which includes the dorsal anterior cingulate and bilateral anterior insula) regulates attention to surroundings, controlling your concentration on tasks. The default mode network, on the other hand, becomes active when a person seems to be doing 'nothing', and becomes less active when a task is being performed.

The study shows that we work better and faster the better the default mode network is suppressed by the task control network. However, when the default mode network is not sufficiently suppressed by the task control network, it sends signals to the task control network, interfering with its performance (and we lose focus).

Interestingly, in certain conditions, such as autism, depression, and mild cognitive impairment, the default mode network remains unchanged whether the person is performing a task or interacting with the environment. Additionally, deficits in the functioning of the default mode network have been implicated in age-related cognitive decline.

The findings add a new perspective to our ideas about attention. One of the ongoing questions concerns the relative importance of the two main aspects of attention: focus, and resisting distraction. A lot of work in recent years has indicated that a large part of age-related cognitive decline is a growing difficulty in resisting distraction. Similarly, there is some evidence that people with a low working memory capacity are less able to ignore irrelevant information.

This recent finding, then, suggests that these difficulties in ignoring distracting / irrelevant stimuli reflect the failure of the task control network to adequately suppress the activity of the default mode network. This puts the emphasis back on training for focus, and may help explain why meditation practices are effective in improving concentration.

http://www.futurity.org/science-technology/why-your-seesaw-brain-cant-stay-on-task/

[3384] Wen X, Liu Y, Yao L, Ding M. Top-Down Regulation of Default Mode Activity in Spatial Visual Attention. The Journal of Neuroscience [Internet]. 2013 ;33(15):6444 - 6453. Available from: http://www.jneurosci.org/content/33/15/6444

Evidence is accumulating that age-related cognitive decline is rooted in three related factors: processing speed slows down (because of myelin degradation); the ability to inhibit distractions becomes impaired; working memory capacity is reduced.

A new study adds to this evidence by looking at one particular aspect of age-related cognitive decline: memory search.

The study put 185 adults aged 29-99 (average age 67) through three cognitive tests: a vocabulary test, digit span (a working memory test), and the animal fluency test, in which you name as many animals as you can in one minute.

Typically, in the animal fluency test, people move through semantic categories such as ‘pets’, ‘big cats’, and so on. The best performers are those who move from category to category with optimal timing — i.e., at the point where the category has been sufficiently exhausted that efforts would be better spent on a new one.

Participants recalled on average 17 animal names, with a range from 5 to 33. While there was a decline with age, it wasn’t particularly marked until the 80s (an average of 18.3 for those in their 30s, 17.5 for those in their 60s, 16.5 for the 70s, 12.8 for the 80s, and 10 for the 90s). Digit span did show a decline, but it was not significant (from 17.5 down to 15.3), while vocabulary (consistent with previous research) showed no decline with age.

But all this is by the by — the nub of the experiment was to discover how individuals were searching their memory. This required a quite complicated analysis, which I will not go into, except to mention two important distinctions. The first is between:

  • global context cue: activates each item in the active category according to how strong it is (how frequently it has been recalled in the past);
  • local context cue: activates each item in relation to its semantic similarity to the previous item recalled.

A further distinction was made between static and dynamic processes: in dynamic models, it is assumed the user switches between local and global search. This, it is further assumed, is because memory is ‘patchy’ – that is, information is represented in clusters. Within a cluster, we use local cues, but to move from one cluster to another, we use global cues.

The point of all this was to determine whether age-related decline in memory search has to do with:

  • Reduced processing speed,
  • Persisting too long on categories, or
  • Inability to maintain focus on local cues (this would relate it back to the inhibition deficit).

By modeling the exact recall patterns, the researchers ascertained that the recall process is indeed dynamic, although the points of transition are not clearly understood. The number of transitions from one cluster to another was negatively correlated with age; it was also strongly positively correlated with performance (number of items recalled). Digit span, assumed to measure ‘cognitive control’, was also negatively correlated with number of transitions, but, as I said, was not significantly correlated with age.

In other words, it appears that there is a qualitative change with age, that increasing age is correlated with increased switching, and reduced cognitive control is behind this — although it doesn’t explain it all (perhaps because we’re still not able to fully measure cognitive control).

At a practical level, the message is that memory search may become less efficient because, as people age, they tend to change categories too frequently, before they have exhausted their full potential. While this may well be a consequence of reduced cognitive control, it seems likely (to me at least) that making a deliberate effort to fight the tendency to move on too quickly will pay dividends for older adults who want to improve their memory retrieval abilities.

Nor is this restricted to older adults — since age appears to be primarily affecting performance through its effects on cognitive control, it is likely that this applies to those with reduced working memory capacity, of any age.

[3378] Hills TT, Mata R, Wilke A, Samanez-Larkin GR. Mechanisms of Age-Related Decline in Memory Search Across the Adult Life Span. Developmental Psychology. 2013 :No - Pagination Specified.

A humanoid robot has been designed, and shows promise, for teaching joint attention to children with ASD. Robots are particularly appealing to children, and even more so to those with ASD.

http://www.futurity.org/health-medicine/interactive-robot-trains-kids-with-autism/

[3351] Bekele ET, Lahiri U, Swanson AR, Crittendon JA, Warren ZE, Sarkar N. A Step Towards Developing Adaptive Robot-Mediated Intervention Architecture (ARIA) for Children With Autism. IEEE Transactions on Neural Systems and Rehabilitation Engineering. 2013 ;21(2):289 - 299.

I’ve reported often on the perils of multitasking. Here is yet another one, with an intriguing new finding: it seems that the people who multitask the most are those least capable of doing so!

The study surveyed 310 undergraduate psychology students to find their actual multitasking ability, perceived multitasking ability, cell phone use while driving, use of a wide array of electronic media, and personality traits such as impulsivity and sensation-seeking.

Those who scored in the top quarter on a test of multitasking ability tended not to multitask. Some 70% of participants thought they were above average at multitasking, and perceived multitasking ability (rather than actual) was associated with multitasking. Those with high levels of impulsivity and sensation-seeking were also more likely to multitask (with the exception of using a cellphone while driving, which wasn’t related to impulsivity, though it was related to sensation seeking).

The findings suggest that those who multitask don’t do so because they are good at multitasking, but because they are poor at focusing on one task.

Another study looking into the urban-nature effect issue takes a different tack than those I’ve previously reported on, that look at the attention-refreshing benefits of natural environments.

In this study, a rural African people living in a traditional village were compared with those who had moved to town. Participants in the first experiment included 35 adult traditional Himba, 38 adolescent traditional Himba (mean age 12), 56 adult urbanized Himba, and 37 adolescent urbanized Himba. All traditional Himba had had little contact with the Western world and only spoke their native language; all adult urbanized Himba had grown up in traditional villages and only moved to town later in life (average length of time in town was 6 years); all adolescent urbanized Himba had grown up in town the town and usually attended school regularly.

The first experiments assessed the ability to ignore peripheral distracting arrows while focusing on the right or left direction of a central arrow.

There was a significant effect of urbanization, with attention being more focused (less distracted) among the traditional Himba. Traditional Himba were also slower than urbanized Himba — but note that there was substantial overlap in response times between the two groups. There was no significant effect of age (that is, adolescents were faster than adults in their responses, but the effect of the distracters was the same across age groups), or a significant interaction between age and urbanization.

The really noteworthy part of this, was that the urbanization effect on task performance was the same for the adults who had moved to town only a few years earlier as for the adolescents who had grown up and been educated in the town. In other words, this does not appear to be an educational effect.

The second experiment looked at whether traditional Himba would perform more like urbanized Himba if there were other demands on working memory. This was done by requiring them to remember three numbers (the number words in participants’ language are around twice as long as the same numbers in English, hence their digit span is shorter).

While traditional Himba were again more focused than the urbanized in the no-load condition, when there was this extra load on working memory, there was no significant difference between the two groups. Indeed, attention was de-focused in the traditional Himba under high load to the same degree as it was for urbanized Himba under no-load conditions. Note that increasing the cognitive load made no difference for the urbanized group.

There was also a significant (though not dramatic) difference between the traditional and urbanized Himba in terms of performance on the working memory task, with traditional Himba remembering an average of 2.46/3 digits and urbanized Himba 2.64.

Experiment 3 tested the two groups on a working memory task, a standard digit span test (although, of course, in their native language). Random sequences of 2-5 digits were read out, with the participant being required to say them aloud immediately after. Once again, the urbanized Himba performed better than the traditional Himba (4.32 vs 3.05).

In other words, the problem does not seem to be that urbanization depletes working memory, rather, that urbanization encourages disengagement (i.e., we have the capacity, we just don’t use it).

In the fourth experiment, this idea was tested more directly. Rather than the arrows used in the earlier experiments, black and white faces were used, with participants required to determine the color of the central face. Additionally, inverted faces were sometimes used (faces are stimuli we pay a lot of attention to, but inverting them reduces their ‘faceness’, thus making them less interesting).

An additional group of Londoners was also included in this experiment.

While urbanized Himba and Londoners were, again, more de-focused than traditional Himba when the faces were inverted, for the ‘normal’ faces, all three groups were equally focused.

Note that the traditional Himba were not affected by the changes in the faces, being equally focused regardless of the stimulus. It was the urbanized groups that became more alert when the stimuli became more interesting.

Because it may have been a race-discrimination mechanism coming into play, the final experiment returned to the direction judgment, with faces either facing left or right. This time the usual results occurred – the urbanized groups were more de-focused than the traditional group.

In other words, just having faces was not enough; it was indeed the racial discrimination that engaged the urbanized participants (note that both these urban groups come from societies where racial judgments are very salient – multicultural London, and post-apartheid Namibia).

All of this indicates that the attention difficulties that appear so common nowadays are less because our complex environments are ‘sapping’ our attentional capacities, and more because we are in a different attentional ‘mode’. It makes sense that in environments that contain so many more competing stimuli, we should employ a different pattern of engagement, keeping a wider, more spread, awareness on the environment, and only truly focusing when something triggers our interest.

[3273] Linnell KJ, Caparos S, de Fockert JW, Davidoff J. Urbanization Decreases Attentional Engagement. Journal of experimental psychology. Human perception and performance. 2013 .

Being a woman of a certain age, I generally take notice of research into the effects of menopause on cognition. A new study adds weight, perhaps, to the idea that cognitive complaints in perimenopause and menopause are not directly a consequence of hormonal changes, but more particularly, shows that early post menopause may be the most problematic time.

The study followed 117 women from four stages of life: late reproductive, early and late menopausal transition, and early postmenopause. The late reproductive period is defined as when women first begin to notice subtle changes in their menstrual periods, but still have regular menstrual cycles. Women in the transitional stage (which can last for several years) experience fluctuation in menstrual cycles, and hormone levels begin to fluctuate significantly.

Women in the early stage of post menopause (first year after menopause), as a group, were found to perform more poorly on measures of verbal learning, verbal memory, and fine motor skill than women in the late reproductive and late transition stages. They also performed significantly worse than women in the late menopausal transition stage on attention/working memory tasks.

Surprisingly, self-reported symptoms such as sleep difficulties, depression, and anxiety did not predict memory problems. Neither were the problems correlated with hormone levels (although fluctuations could be a factor).

This seemingly contradicts earlier findings from the same researchers, who in a slightly smaller study found that those experiencing poorer working memory and attention were more likely to have poorer sleep, depression, and anxiety. That study, however, only involved women approaching and in menopause. Moreover, these aspects were not included in the abstract of the paper but only in the press release, and because I don’t have access to this particular journal, I cannot say whether there is something in the data that explains this. Because of this, I am not inclined to put too much weight on this point.

But we may perhaps take the findings as support for the view that cognitive problems experienced earlier in the menopause cycle are, when they occur, not a direct result of hormonal changes.

The important result of this study is the finding that the cognitive problems often experienced by women in their 40s and 50s are most acute during the early period of post menopause, and the indication that the causes and manifestations are different at different stages of menopause.

It should be noted, however, that there were only 14 women in the early postmenopause stage. So, we shouldn’t put too much weight on any of this. Nevertheless, it does add to the picture research is building up about the effects of menopause on women’s cognition.

While the researchers said that this effect is probably temporary — which was picked up as the headline in most media — this was not in fact investigated in this study. It would be nice to have some comparison with those, say, two or three and five years post menopause (but quite possibly this will be reported in a later paper).

[3237] Weber MT, Rubin LH, Maki PM. Cognition in perimenopause. Menopause: The Journal of The North American Menopause Society [Internet]. 2013 . Available from: http://journals.lww.com/menopausejournal/Abstract/publishahead/Cognition_in_perimenopause___the_effect_of.98696.aspx

The issue of ‘chemo-brain’ — cognitive impairment following chemotherapy — has been a controversial one. While it is now (I hope) accepted by most that it is, indeed, a real issue, there is still an ongoing debate over whether the main cause is really the chemotherapy. A new study adds to the debate.

The study involved 28 women who received adjuvant chemotherapy for breast cancer, 37 who received radiotherapy, and 32 age-matched healthy controls. Brain scans while doing a verbal working memory task were taken before treatment and one month after treatment.

Women who underwent chemotherapy performed less accurately on the working memory task both before treatment and one month after treatment. They also reported a significantly higher level of fatigue. Greater fatigue correlated with poorer test performance and more cognitive problems, across both patient groups and at both times (although the correlation was stronger after treatment).

Both patient groups showed reduced function in the left inferior frontal gyrus, before therapy, but those awaiting chemotherapy showed greater impairment than those in the radiotherapy group. Pre-treatment difficulty in recruiting this brain region in high demand situations was associated with greater fatigue after treatment.

In other words, reduced working memory function before treatment began predicted how tired people felt after treatment, and how much their cognitive performance suffered. All of which suggests it is not the treatment itself that is the main problem.

But the fact that reduced working memory function precedes the fatigue indicates it’s not the fatigue that’s the main problem either. The researchers suggest that the main driver is level of worry —worry interfered with the task; level of worry was related to fatigue. And worry, as we know, can reduce working memory capacity (because it uses up part of it).

All of which is to say that support for cancer patients aimed at combating stress and anxiety might do more for ‘chemo-brain’ than anything else. In this context, I note also that there have been suggestions that sleep problems have also been linked to chemo-brain — a not unrelated issue!

Cimprich, B. et al. 2012. Neurocognitive impact in adjuvant chemotherapy for breast cancer linked to fatigue: A Prospective functional MRI study. Presented at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium, Dec. 4-8

There have been a number of studies in the past few years showing how poverty affects brain development and function. One of these showed specifically that children of high and low socioeconomic status showed differences in brain wave patterns associated with an auditory selective attention task. This was thought to indicate that the groups were using different mechanisms to carry out the task, with the lower SES children employing extra resources to attend to irrelevant information.

In a follow-up study, 28 young adolescents (12-14 years) from two schools in neighborhoods of different socioeconomic status answered questions about their emotional and motivational state at various points during the day, and provided saliva samples to enable monitoring of cortisol levels. At one point in the afternoon, they also had their brainwaves monitored while they carried out an auditory selective attention task (hearing different sounds played simultaneously into both ears, they were required to press a button as fast as possible when they heard one particular sound).

While performance on the task was the same for both groups, there were, once again, differences in the brain wave patterns. Higher SES children exhibited far larger theta waves in the frontal lobes in response to sounds they attended to than to compared to those they should have ignored, while lower SES children showed much larger theta waves to the unattended sounds than for the attended sounds.

While the lower SES children had higher cortisol levels throughout the school day, like the higher SES children, they showed little change around the task, suggesting neither group was particularly stressed by the task. Both groups also showed similar levels of boredom and motivation.

What the findings suggest is that lower SES children have to exert more cognitive control to avoid attending to irrelevant stimuli than higher SES children — perhaps because they live in more threatening environments.

Stress is a major cause of workplace accidents, and most of us are only too familiar with the effects of acute stress on our thinking. However, although the cognitive effects are only too clear, research has had little understanding of how stress has this effect. A new rat study sheds some light.

In the study, brain activity was monitored while five rats performed a working memory task during acute noise stress. Under these stressful conditions, the rats performed dramatically worse on their working memory task, with performance dropping from an average of 93% success to 65%.

The stress also significantly increased the discharge rate of a subset of neurons in the medial prefrontal cortex during two phases of the task: planning and assessment.

This brain region is vital for working memory and executive functions such as goal maintenance and emotion regulation. The results suggest that the firing and re-firing of these neurons keeps recent information ‘fresh’. When the re-firing is delayed, the information can be lost.

What seems to be happening is that the stress is causing these neurons to work even more furiously, but instead of performing their normal task — concentrating on keeping important information ‘alive’ during brief delays — they are reacting to all the other, distracting and less relevant, stimuli.

The findings contradict the view that stress simply suppresses prefrontal cortex activity, and suggests a different approach to treatment, one that emphasizes shutting out distractions.

The findings are also exciting from a theoretical viewpoint, suggesting as they do that this excitatory recursive activity of neurons within the prefrontal cortex provide the neural substrate for working memory. That is, that we ‘hold’ information in the front of our mind through reverberating feedback loops within this network of neurons, that keep information alive during the approximately 1.5 seconds of our working memory ‘span’.

A large long-running New Zealand study has found that people who started using cannabis in adolescence and continued to use it for years afterward showed a significant decline in IQ from age 13 to 38. This was true even in those who hadn’t smoked marijuana for some years.

The study has followed a group of 1,037 children born in 1972-73. At age 38, 96% of the 1004 living study members participated in the latest assessment. Around 5% were regularly smoking marijuana more than once a week before age 18 (cannabis use was ascertained in interviews at ages 18, 21, 26, 32, and 38 years, and this group was not more or less likely to have dropped out of the study).

This group showed an average decline in IQ of 8 points on cognitive tests at age 38 compared to scores at age 13. Such a decline was not found in those who began using cannabis after the age of 18. In comparison, those who had never used cannabis showed a slight increase in IQ. The effect was dose-dependent, with those diagnosed as cannabis dependent on three or more occasions showing the greatest decline.

While executive function and processing speed appeared to be the most seriously affected areas, impairment was seen across most cognitive domains and did not appear to be statistically significantly different across them.

The size of the effect is shown by a further measure: informants (nominated by participants as knowing them well) also reported significantly more attention and memory problems among those with persistent cannabis dependence. (Note that a decline of 8 IQ points in a group whose mean is 100 brings it down to 92.)

The researchers ruled out recent cannabis use, persistent dependence on other drugs (tobacco, alcohol, hard drugs), and schizophrenia, as alternative explanations for the effect. The effect also remained after years of education were taken into account.

The finding supports the view that the adolescent brain is vulnerable to the effects of marijuana, and that these effects are long-lasting and significant.

Some numbers for those interested: Of the 874 participants included in the analysis (those who had missed at least 3 interviews in the 25 years were excluded), 242 (28%) never used cannabis, 479 (55%) used it but were never diagnosed as cannabis-dependent, and 153 (17%) were diagnosed on at least one of the interviews as cannabis-dependent. Of these, 80 had been so diagnosed on only one occasion, 35 on two occasions, and 38 on three or more occasions. I note that the proportion of males was significantly higher in the cannabis-dependent groups (39% in never used; 49% in used but never diagnosed; 70%, 63%, 82% respectively for the cannabis-dependent).

Meditation may improve multitasking

I recently reported that developing skill at video action games doesn’t seem to improve general multitasking ability, but perhaps another approach might be more successful. Meditation has, of course, been garnering growing evidence that it can help improve attentional control. A new study extends that research to multitasking in a realistic work setting.

The study involved three groups of 12-15 female human resource managers, of whom one group received eight weeks of mindfulness-based meditation training, another received eight weeks of body relaxation training, and another initially received no training (control), before receiving the mindfulness training after the eight weeks.

Before and after each eight-week period, the participants were given a stressful test of their multitasking abilities, requiring them to use email, calendars, instant-messaging, telephone and word-processing tools to perform common office tasks (scheduling a meeting; finding a free conference room; writing a draft announcement of the meeting, eating snacks and drinking water, writing a memo proposing a creative agenda item for the meeting). Necessary information came from emails, instant messages, telephone calls, and knocks on the door. The participants had 20 minutes to complete the tasks.

The meditation group reported lower levels of stress during the multitasking test compared to the control and relaxation groups. They also spent more time on tasks and switched tasks less often, while taking no longer to complete the overall job than the others. Both meditation and relaxation groups showed improved memory for the tasks they were performing.

After the control group underwent the meditation training, their results matched those of the meditation group.

The meditation training emphasized:

  • control of attentional focus
  • focusing attention in the present moment or task
  • switching focus
  • breath and body awareness.

The relaxation training emphasized progressive tensing and relaxing of major muscle groups, aided by relaxation imagery.

It's interesting that overall time on task didn't change (the researchers remarked that the meditators didn't take any longer, but of course most of us would be looking for it to become shorter!), but I wouldn't read too much into it. The task was relatively brief. It would be interesting to see the effects over the course of, say, a day. Nor did the study look at how well the tasks were done.

But it is, of course, important that meditation training reduced task-switching and stress. Whether it also has a postitive effect on overall time and quality of work is a question for another day.

IBMT improves white matter efficiency

A recent imaging study has found that four weeks of a form of mindfulness meditation called integrative body–mind training (IBMT) improved white matter efficiency in areas surrounding the anterior cingulate cortex, compared to controls given relaxation training.

The anterior cingulate is part of the brain network related to self-regulation. Deficits in activation in this part of the brain have been associated with attention deficit disorder, dementia, depression, schizophrenia, and other disorders.

Using the data from a 2010 study involving 45 U.S. college students, and another involving 68 Chinese students, researchers found that axon density (one factor in white matter efficiency) had improved after two weeks, but not myelin formation. After a month (about 11 hours of meditation), both had improved. Mood improved by two weeks.

Previous studies involving computer-based training for improving working memory have found changes in myelination, but not axon density.

Meditators’ better cognitive control may be rooted in emotional regulation

Previous work has found that people who engage in meditation show higher levels of executive control on laboratory tasks.

An electrical signal called the Error Related Negativity (ERN) occurs in the brain within 100 ms of an error being committed. When meditators and non-meditators were given the Stroop Test, meditators not only tended to do better on the test, but their ERNs were stronger.

The interesting thing about this is that the best performers were those who scored highest on emotional acceptance. Mindful awareness was less important. It’s suggested that meditators may be able to control their behavior better not because of their sharper focus, but because they are more aware of their emotions and regulate them better.

Something to think about!

Levy, D. M., Wobbrock, J. O., Kaszniak, A. W., & Ostergren, M. (2012). The Effects of Mindfulness Meditation Training on Multitasking in a High-Stress Information Environment, 45–52. Full text available at http://faculty.washington.edu/wobbrock/pubs/gi-12.02.pdf

[3051] Tang Y-Y, Lu Q, Fan M, Yang Y, Posner MI. Mechanisms of white matter changes induced by meditation. Proceedings of the National Academy of Sciences [Internet]. 2012 ;109(26):10570 - 10574. Available from: http://www.pnas.org/content/109/26/10570

[3052] Teper R, Inzlicht M. Meditation, mindfulness and executive control: the importance of emotional acceptance and brain-based performance monitoring. Social Cognitive and Affective Neuroscience [Internet]. 2012 . Available from: http://scan.oxfordjournals.org/content/early/2012/05/13/scan.nss045

I’ve talked before about Dr Berman’s research into Attention Restoration Theory, which proposes that people concentrate better after nature walks or even just looking at nature scenes. In his latest study, the findings have been extended to those with clinical depression.

The study involved 20 young adults (average age 26), all of whom had a diagnosis of major depressive disorder. Short-term memory and mood were assessed (using the backwards digit span task and the PANAS), and then participants were asked to think about an unresolved, painful autobiographical experience. They were then randomly assigned to go for a 50-minute walk along a prescribed route in either the Ann Arbor Arboretum (woodland park) or traffic heavy portions of downtown Ann Arbor. After the walk, mood and cognition were again assessed. A week later the participants repeated the entire procedure in the other location.

Participants exhibited a significant (16%) increase in attention and working memory after the nature walk compared to the urban walk. While participants felt more positive after both walks, there was no correlation with memory effects.

The finding is particularly interesting because depression is characterized by high levels of rumination and negative thinking. It seemed quite likely, then, that a solitary walk in the park might make depressed people feel worse, and worsen working memory. It’s intriguing that it didn’t.

It’s also worth emphasizing that, as in earlier studies, this effect of nature on cognition appears to be independent of mood (which is, of course, the basic tenet of Attention Restoration Theory).

Of course, this study is, like the others, small, and involves the same demographic. Hopefully future research will extend the sample groups, to middle-aged and older adults.

A study involving 75 perimenopausal women aged 40 to 60 has found that those with memory complaints tended to show impairments in working memory and attention. Complaints were not, however, associated with verbal learning or memory.

Complaints were also associated with depression, anxiety, somatic complaints, and sleep disturbance. But they weren’t linked to hormone levels (although estrogen is an important hormone for learning and memory).

What this suggests to me is that a primary cause of these cognitive impairments may be poor sleep, and anxiety/depression. A few years ago, I reported on a study that found that, although women’s reports of how many hot flashes they had didn’t correlate with memory impairment, an objective measure of the number of flashes they experienced during sleep did. Sleep, as I know from personal experience, is of sufficient importance that my rule-of-thumb is: don’t bother looking for any other causes of attention and memory deficits until you have sorted out your sleep!

Having said that, depressive symptoms showed greater relationship to memory complaints than sleep disturbance.

It’s no big surprise to hear that it is working memory in particular that is affected, because what many women at this time of life complain of is ‘brain fog’ — the feeling that your brain is full of cotton-wool. This doesn’t mean that you can’t learn new information, or remember old information. But it does mean that these tasks will be impeded to the extent that you need to hold on to too many bits of information. So mental arithmetic might be more difficult, or understanding complex sentences, or coping with unexpected disruptions to your routine, or concentrating on a task for a long time.

These sorts of problems are typical of those produced by on-going sleep deprivation, stress, and depression.

One caveat to the findings is that the study participants tended to be of above-average intelligence and education. This would protect them to a certain extent from cognitive decline — those with less cognitive reserve might display wider impairment. Other studies have found verbal memory, and processing speed, impaired during menopause.

Note, too, that a long-running, large population study has found no evidence for a decline in working memory, or processing speed, in women as they pass through perimenopause and menopause.

A three-year study involving 3,034 Singaporean children and adolescents (aged 8-17) has found that those who spent more time playing video games subsequently had more attention problems, even when earlier attention problems, sex, age, race, and socioeconomic status were statistically controlled. Those who were more impulsive or had more attention problems subsequently spent more time playing video games, even when initial video game playing was statistically controlled. These findings suggest that the cause-effect relationship between video game playing and attention problems/impulsiveness goes both ways.

While the particular content may have an effect on attention problems and impulsiveness (violent games appeared to be an additional, independent, factor in attention problems), it was the total time spent that was more important.

Participants completed questionnaires about their video game playing habits annually for three years running. They also completed questionnaires aimed to measure attention and impulsiveness (the Current ADHD Symptoms Scale Self-Report, and the Barratt Impulsiveness Scale-11, respectively). Regarding attention, the children answered questions such as how often they "fail to give close attention to details or make careless mistakes" in their work or "blurt out answers before questions have been completed." For the impulsivity test, they selected points they felt described themselves, such as "I often make things worse because I act without thinking" or "I concentrate easily."

How does this finding relate to other evidence showing that playing video games can improve visual attention for rapid and accurate recognition of information from the environment? The answer lies in the different nature of attention — the attention needed for visual search differs in important ways from the attention necessary for sustained concentration in contexts that are often effortful and/or boring.

The example of many attention-challenged individuals makes this more understandable. Many parents of children with ADHD find that the only thing their child can concentrate on for a lengthy period is video games. The answer to that riddle is the rapidly changing nature of video games, and the way they are designed to grab the attention, with flashing lights and loud noises and moving images etc. The young person is not, therefore, improving their ability to focus in a way that is helpful for the school environment, or indeed for everyday life.

Unfortunately, this study suggests that it is precisely those people who are most in need of such ‘external supports’ for attention (‘grabbing’ stimuli such as lights and sounds and movement) — that is, those individuals who are least able to control their own attention — who are most likely to spend a lot of time playing such games. The games then weaken their attentional control even more, and so the cycle continues.

So this research answers the question ADHD parents tend to have: should I encourage my child to play video games a lot (given that it’s the only thing that holds their attention) or not? The answer, unfortunately, would seem to be: not. However, all is not lost. There are computer ‘games’ that are designed to help those with ADHD learn to concentrate in a way that is more useful (see the Topic collection on ADHD for more on this).

The American Academy of Pediatrics recommends one hour per day of total media screen time (including TV, DVDs, video games, Internet, iPad, etc.) for children in elementary school, and two hours for children in secondary school.

Gentile, D.A., Swing, E.L., Lim, C.G. & Khoo, A. 2012. Video game playing, attention problems, and impulsiveness: Evidence of bidirectional causality. Psychology of Popular Media Culture, Vol 1(1), Jan 2012, 62-70. doi: 10.1037/a0026969

Full text available at http://www.apa.org/pubs/journals/releases/ppm-1-1-62.pdf

Quarter of British children performing poorly due to family disadvantage

A British study involving over 18,000 very young children (aged 9 months to 5 years) has found that those exposed to two or more “disadvantages” (28% of the children) were significantly more likely to have impaired intellectual development, expressed in a significantly reduced vocabulary and behavioral problems.

These differences were significant at three, and for the most part tended to widen between ages three or five (cognitive development, hyperactivity, peer problems and prosocial behaviors; the gap didn’t change for emotional problems, and narrowed for conduct problems). However, only the narrowing of the conduct problem gap and the widening of the peer problem gap was statistically significant.

Ten disadvantages were identified: living in overcrowded housing; having a teenage mother; having one or more parents with depression, parent with a physical disability; parent with low basic skills; maternal smoking during pregnancy; excessive alcohol intake; financial stress, unemployment; domestic violence..

Around 41% of the children did not face any of these disadvantages, and 30% faced only one of these disadvantages. Of those facing two or more, half of those (14%) only had two, while 7% of the total group experienced three risk factors, and fewer than 2% had five or more.

There was no dominant combination of risks, but parental depression was the most common factor (19%), followed by parental disability (15%). Violence was present in only 4% of families, and both parents unemployed in only 5.5%. While there was some correlation between various risk factors, these correlations were relatively modest for the most part. The highest correlations were between unemployment and disability; violence and depression; unemployment and overcrowding.

There were ethnic differences in rate: at 48%, Bangladeshi children were most likely to be exposed to multiple disadvantages, followed by Pakistani families (34%), other (including mixed) (33%), black African (31%), black Caribbean (29%), white (28%) and Indian (20%).

There were also differences depending on family income. Among those in the lowest income band (below £10,400 pa) — into which 21% of the families fell, the same proportion as is found nationally — nearly half had at least two risk factors, compared to 27% of those in families above this threshold. Moreover, children in families with multiple risk factors plus low income showed the lowest cognitive development (as measured by vocabulary).

Childhood maltreatment reduces size of hippocampus

In this context, it is interesting to note a recent finding that three key areas of the hippocampus were significantly smaller in adults who had experienced maltreatment in childhood. In this study, brain scans were taken of nearly 200 young adults (18-25), of whom 46% reported no childhood adversity and 16% reported three or more forms of maltreatment. Maltreatment was most commonly physical and verbal abuse from parents, but also included corporal punishment, sexual abuse and witnessing domestic violence.

Reduced volume in specific hippocampus regions (dentate gyrus, cornu ammonis, presubiculum and subiculum) was still evident after such confounding factors as a history of depression or PTSD were taken into account. The findings support the theory that early stress affects the development of subregions in the hippocampus.

While mother’s nurturing grows the hippocampus

Supporting this, another study, involving 92 children aged 7 to 10 who had participated in an earlier study of preschool depression, has found that those children who received a lot of nurturing from their parent (generally mother) developed a larger hippocampus than those who didn’t.

‘Nurturing’ was assessed in a videotaped interaction at the time of the preschool study. In this interaction, the parent performed a task while the child waited for her to finish so they could open an attractive gift. How the parent dealt with this common scenario — the degree to which they helped the child through the stress — was evaluated by independent raters.

Brain scans revealed that children who had been nurtured had a significantly larger hippocampus than those whose mothers were not as nurturing, and (this was the surprising bit), this effect was greater among the healthy, non-depressed children. Among this group, those with a nurturing parent had hippocampi which were on average almost 10% larger than those whose parent had not been as nurturing.

First study:
Sabates, R., Dex, S., Sabates, R., & Dex, S. (2012). Multiple risk factors in young children’s development. CLS Cohort Studies Working paper 2012/1.
Full text available at http://www.cls.ioe.ac.uk/news.aspx?itemid=1661&itemTitle=More+than+one+i...

Second study:
[2741] Teicher MH, Anderson CM, Polcari A. Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum. Proceedings of the National Academy of Sciences [Internet]. 2012 . Available from: http://www.pnas.org/content/early/2012/02/07/1115396109.abstract?sid=f7347fbd-20b6-429c-a0b4-c3d666c460cd
Full text available at http://www.pnas.org/content/early/2012/02/07/1115396109.abstract?sid=f73...

Third study:
[2734] Luby JL, Barch DM, Belden A, Gaffrey MS, Tillman R, Babb C, Nishino T, Suzuki H, Botteron KN. Maternal support in early childhood predicts larger hippocampal volumes at school age. Proceedings of the National Academy of Sciences [Internet]. 2012 . Available from: http://www.pnas.org/content/early/2012/01/24/1118003109

The study involved 1,292 children followed from birth, whose cortisol levels were assessed at 7, 15, and 24 months. Three tests related to executive functions were given at age 3. Measures of parenting quality (maternal sensitivity, detachment, intrusiveness, positive regard, negative regard, and animation, during interaction with the child) and household environment (household crowding, safety and noise levels) were assessed during the home visits.

Earlier studies have indicated that a poor environment in and of itself is stressful to children, and is associated with increased cortisol levels. Interestingly, in one Mexican study, preschool children in poor homes participating in a conditional cash transfer scheme showed reduced cortisol levels.

This study found that children in lower-income homes received less positive parenting and had higher levels of cortisol in their first two years than children in slightly better-off homes. Higher levels of cortisol were associated with lower levels of executive function abilities, and to a lesser extent IQ, at 3 years.

African American children were more affected than White children on every measure. Cortisol levels were significantly higher; executive function and IQ significantly lower; ratings of positive parenting significantly lower and ratings of negative parenting significantly higher. Maternal education was significantly lower, poverty greater, homes more crowded and less safe.

The model derived from this data shows executive function negatively predicted by cortisol, while the effect on IQ is marginal. However, both executive function and IQ are predicted by negative parenting, positive parenting, and household risk (although this last variable has a greater effect on IQ than executive function). Neither executive function nor IQ was directly predicted by maternal education, ethnicity, or poverty level. Cortisol level was inversely related to positive parenting, but was not directly related to negative parenting or household risk.

Indirectly (according to this best-fit model), poverty was related to executive function through negative parenting; maternal education was related to executive function through negative parenting and to a lesser extent positive parenting; both poverty and maternal education were related to IQ through positive parenting, negative parenting, and household risk; African American ethnicity was related to executive function through negative parenting and positive parenting, and to IQ through negative parenting, positive parenting, and household risk. Cortisol levels were higher in African American children and this was unrelated to poverty level or maternal education.

Executive function (which includes working memory, inhibitory control, and attention shifting) is vital for self-regulation and central to early academic achievement. A link between cortisol level and executive function has previously been shown in preschool children, as well as adults. The association partly reflects the fact that stress hormone levels affect synaptic plasticity in the prefrontal cortex, where executive functions are carried out. This is not to say that this is the only brain region so affected, but it is an especially sensitive one. Chronic levels of stress alter the stress response systems in ways that impair flexible regulation.

What is important about this study is this association between stress level and cognitive ability at an early age, that the effect of parenting on cortisol is associated with positive aspects rather than negative ones, and that the association between poverty and cognitive ability is mediated by both cortisol and parenting behavior — both positive and negative aspects.

A final word should be made on the subject of the higher cortisol levels in African Americans. Because of the lack of high-income African Americans in the sample (a reflection of the participating communities), it wasn’t possible to directly test whether the effect is accounted for by poverty. So this remains a possibility. It is also possible that there is some genetic difference. But it also might reflect other sources of stress, such as that relating to prejudice and stereotype threat.

Based on mother’s ethnic status, 58% of the families were Caucasian and 42% African American. Two-thirds of the participants had an income-to-need ratio (estimated total household income divided by the 2005 federal poverty threshold adjusted for number of household members) less than 200% of poverty. Just over half of the mothers weren’t married, and most of them (89%) had never been married. The home visits at 7, 15, and 24 months lasted at least an hour, and include a videotaped free play or puzzle completion interaction between mother and child. Cortisol samples were taken prior to an emotion challenge task, and 20 minutes and 40 minutes after peak emotional arousal.

Long-term genetic effects of childhood environment

The long-term effects of getting off to a poor start are deeper than you might believe. A DNA study of forty 45-year-old males in a long-running UK study has found clear differences in gene methylation between those who experienced either very high or very low standards of living as children or adults (methylation of a gene at a significant point in the DNA reduces the activity of the gene). More than twice as many methylation differences were associated with the combined effect of the wealth, housing conditions and occupation of parents (that is, early upbringing) than were associated with the current socio-economic circumstances in adulthood (1252 differences as opposed to 545).

The findings may explain why the health disadvantages known to be associated with low socio-economic position can remain for life, despite later improvement in living conditions. The methylation profiles associated with childhood family living conditions were clustered together in large stretches of DNA, which suggests that a well-defined epigenetic pattern is linked to early socio-economic environment. Adult diseases known to be associated with early life disadvantage include coronary heart disease, type 2 diabetes and respiratory disorders.

[2589] Blair C, Granger DA, Willoughby M, Mills-Koonce R, Cox M, Greenberg MT, Kivlighan KT, Fortunato CK, the Investigators FLP. Salivary Cortisol Mediates Effects of Poverty and Parenting on Executive Functions in Early Childhood. Child Development [Internet]. 2011 :no - no. Available from: http://dx.doi.org/10.1111/j.1467-8624.2011.01643.x

Fernald, L. C., & Gunnar, M. R. (2009). Poverty-alleviation program participation and salivary cortisol in very low-income children. Social Science and Medicine, 68, 2180–2189.

[2590] Borghol N, Suderman M, McArdle W, Racine A, Hallett M, Pembrey M, Hertzman C, Power C, Szyf M. Associations with early-life socio-economic position in adult DNA methylation. International Journal of Epidemiology [Internet]. 2011 . Available from: http://ije.oxfordjournals.org/content/early/2011/10/18/ije.dyr147.abstract

In yet another study of the effects of pollution on growing brains, it has been found that children who grew up in Mexico City (known for its very high pollution levels) performed significantly worse on cognitive tests than those from Polotitlán, a city with a strong air quality rating.

The study involved 30 children aged 7 or 8, of whom 20 came from Mexico City, and 10 from Polotitlán. Those ten served as controls to the Mexico City group, of whom 10 had white matter hyperintensities in their brains, and 10 had not. Regardless of the presence of lesions, MC children were found to have significantly smaller white matter volumes in right parietal and bilateral temporal regions. Such reduced volumes were correlated with poorer performance on a variety of cognitive tests, especially those relating to attention, working memory, and learning.

It’s suggested that exposure to air pollution disturbs normal brain development, resulting in cognitive deficits.

Math-anxiety can greatly lower performance on math problems, but just because you suffer from math-anxiety doesn’t mean you’re necessarily going to perform badly. A study involving 28 college students has found that some of the students anxious about math performed better than other math-anxious students, and such performance differences were associated with differences in brain activity.

Math-anxious students who performed well showed increased activity in fronto-parietal regions of the brain prior to doing math problems — that is, in preparation for it. Those students who activated these regions got an average 83% of the problems correct, compared to 88% for students with low math anxiety, and 68% for math-anxious students who didn’t activate these regions. (Students with low anxiety didn’t activate them either.)

The fronto-parietal regions activated included the inferior frontal junction, inferior parietal lobule, and left anterior inferior frontal gyrus — regions involved in cognitive control and reappraisal of negative emotional responses (e.g. task-shifting and inhibiting inappropriate responses). Such anticipatory activity in the fronto-parietal region correlated with activity in the dorsomedial caudate, nucleus accumbens, and left hippocampus during math activity. These sub-cortical regions (regions deep within the brain, beneath the cortex) are important for coordinating task demands and motivational factors during the execution of a task. In particular, the dorsomedial caudate and hippocampus are highly interconnected and thought to form a circuit important for flexible, on-line processing. In contrast, performance was not affected by activity in ‘emotional’ regions, such as the amygdala, insula, and hypothalamus.

In other words, what’s important is not your level of anxiety, but your ability to prepare yourself for it, and control your responses. What this suggests is that the best way of dealing with math anxiety is to learn how to control negative emotional responses to math, rather than trying to get rid of them.

Given that cognitive control and emotional regulation are slow to mature, it also suggests that these effects are greater among younger students.

The findings are consistent with a theory that anxiety hinders cognitive performance by limiting the ability to shift attention and inhibit irrelevant/distracting information.

Note that students in the two groups (high and low anxiety) did not differ in working memory capacity or in general levels of anxiety.

Data from parents and teachers of 2000 randomly selected children has revealed that only 29% of children with attention problems finished high school compared to 89% of children without such problems. When it came to hyperactivity, the difference was smaller: 40% versus 77%. After taking account of factors such as socioeconomic status and health issues that are correlated with ADHD, inattention was still a highly significant contributor, but hyperactivity was not.

Yearly assessments of the children were taken from age 6 to 12, and high school graduation status was obtained from official records. Attention problems were evaluated by teachers on the basis of behavior such as an inability to concentrate, absentmindedness, or a tendency to give up or be easily distracted. Hyperactivity was identified by behavior such as restlessness, running around, squirming and being fidgety.

The researchers make the excellent point that those with attention difficulties are often forgotten because, unlike hyperactive children, they don't disturb the class.

The findings point to the need to distinguish inattention and hyperactivity, and to provide early preventive intervention for attention problems.

One survey of nearly 200 undergraduate college students who were not living with a parent or legal guardian found that 55% reported getting less than seven hours sleep. This is consistent with other surveys. The latest study confirms such a result, but also finds that students tend to think their sleep quality is better than it is (70% of students surveyed described their sleep as "fairly good" or better). It’s suggested that this disconnect arises from students making comparisons in an environment where poor sleep is common — even though they realized, on being questioned, that poor sleep undermined their memory, concentration, class attendance, mood, and enthusiasm.

None of this is surprising, of course. But this study did something else — it tried to help.

The researchers launched a campuswide media campaign consisting of posters, student newspaper advertisements and a "Go to Bed SnoozeLetter", all delivering information about the health effects of sleep and tips to sleep better, such as keeping regular bedtime and waking hours, exercising regularly, avoiding caffeine and nicotine in the evening, and so on. The campaign cost less than $2,500, and nearly 10% (90/971) said it helped them sleep better.

Based on interviews conducted as part of the research, the researchers compiled lists of the top five items that helped and hindered student sleep:

Helpers

  • Taking time to de-stress and unwind
  • Creating a room atmosphere conducive to sleep
  • Being prepared for the next day
  • Eating something
  • Exercising

Hindrances

  • Dorm noise
  • Roommate (both for positive/social reasons and negative reasons)
  • Schoolwork
  • Having a room atmosphere not conducive to sleep
  • Personal health issues

In another study, this one involving 142 Spanish schoolchildren aged 6-7, children who slept less than 9 hours and went to bed late or at irregular times showed poorer academic performance. Regular sleep habits affected some specific skills independent of sleep duration.

69% of the children returned home after 9pm at least three evenings a week or went to bed after 11pm at least four nights a week.

And a recent study into the effects of sleep deprivation points to open-ended problem solving being particularly affected. In the study, 35 West Point cadets were given two types of categorization task. The first involved cate­gorizing drawings of fictional animals as either “A” or “not A”; the second required the students to sort two types of fic­tional animals, “A” and “B.” The two tests were separated by 24 hours, during which half the students had their usual night’s sleep, and half did not.

Although the second test required the students to learn criteria for two animals instead of one, sleep deprivation impaired performance on the first test, not the second.

These findings suggest the fault lies in attention lapses. Open-ended tasks, as in the first test, require more focused attention than those that offer two clear choices, as the second test did.

News reports on sleep deprivation are collated here.

[2521] Orzech KM, Salafsky DB, Hamilton LA. The State of Sleep Among College Students at a Large Public University. Journal of American College Health [Internet]. 2011 ;59:612 - 619. Available from: http://www.tandfonline.com/doi/abs/10.1080/07448481.2010.520051

[2515] Cladellas R, Chamarro A, del Badia MM, Oberst U, Carbonell X. Efectos de las horas y los habitos de sueno en el rendimiento academico de ninos de 6 y 7 anos: un estudio preliminarEffects of sleeping hours and sleeping habits on the academic performance of six- and seven-year-old children: A preliminary study. Cultura y Educación. 2011 ;23(1):119 - 128.

Maddox WT; Glass BD; Zeithamova D; Savarie ZR; Bowen C; Matthews MD; Schnyer DM. The effects of sleep deprivation on dissociable prototype learning systems. SLEEP 2011;34(3):253-260.

Working memory capacity and level of math anxiety were assessed in 73 undergraduate students, and their level of salivary cortisol was measured both before and after they took a stressful math test.

For those students with low working memory capacity, neither cortisol levels nor math anxiety made much difference to their performance on the test. However, for those with higher WMC, the interaction of cortisol level and math anxiety was critical. For those unafraid of math, the more their cortisol increased during the test, the better they performed; but for those anxious about math, rising cortisol meant poorer performance.

It’s assumed that low-WMC individuals were less affected because their performance is lower to start with (this shouldn’t be taken as an inevitability! Low-WMC students are disadvantaged in a domain like math, but they can learn strategies that compensate for that problem). But the effect on high-WMC students demonstrates how our attitude and beliefs interact with the effects of stress. We may all have the same physiological responses, but we interpret them in different ways, and this interpretation is crucial when it comes to ‘higher-order’ cognitive functions.

Another study investigated two theories as why people choke under pressure: (a) they’re distracted by worries about the situation, which clog up their working memory; (b) the stress makes them pay too much attention to their performance and become self-conscious. Both theories have research backing from different domains — clearly the former theory applies more to the academic testing environment, and the latter to situations involving procedural skill, where explicit attention to the process can disrupt motor sequences that are largely automatic.

But it’s not as simple as one effect applying to the cognitive domain, and one to the domain of motor skills, and it’s a little mysterious why pressure could have too such opposite effects (drawing attention away, or toward). This new study carried out four experiments in order to define more precisely the characteristics of the environment that lead to these different effects, and suggest solutions to the problem.

In the first experiment, participants were given a category learning task, in which some categories had only one relevant dimension and could be distinguished according to one easily articulated rule, and others involved three relevant dimensions and one irrelevant one. Categorization in this case was based on a complex rule that would be difficult to verbalize, and so participants were expected to integrate the information unconsciously.

Rule-based category learning was significantly worse when participants were also engaged in a secondary task requiring them to monitor briefly appearing letters. However it was not affected when their secondary task involved them explicitly monitoring the categorization task and making a confidence judgment. On the other hand, the implicit category learning task was not disrupted by the letter-monitoring task, but was impaired by the confidence-judgment task. Further analysis revealed that participants who had to do the confidence-judgment task were less likely to use the best strategy, but instead persisted in trying to verbalize a one- or two-dimension rule.

In the second experiment, the same tasks were learned in a low-pressure baseline condition followed by either a low-pressure control condition or one of two high-pressure conditions. One of these revolved around outcome — participants would receive money for achieving a certain level of improvement in their performance. The other put pressure on the participants through monitoring — they were watched and videotaped, and told their performance would be viewed by other students and researchers.

Rule-based category learning was slower when the pressure came from outcomes, but not when the pressure came from monitoring. Implicit category learning was unaffected by outcome pressure, but worsened by monitoring pressure.

Both high-pressure groups reported the same levels of pressure.

Experiment 3 focused on the detrimental combinations — rule-based learning under outcome pressure; implicit learning under monitoring pressure — and added the secondary tasks from the first experiment.

As predicted, rule-based categories were learned more slowly during conditions of both outcome pressure and the distracting letter-monitoring task, but when the secondary task was confidence-judgment, the negative effect of outcome pressure was counteracted and no impairment occurred. Similarly, implicit category learning was slowed when both monitoring pressure and the confidence-judgment distraction were applied, but was unaffected when monitoring pressure was counterbalanced by the letter task.

The final experiment extended the finding of the second experiment to another domain — procedural learning. As expected, the motor task was significantly affected by monitoring pressure, but not by outcome pressure.

These findings suggest two different strategies for dealing with choking, depending on the situation and the task. In the case of test-taking, good test preparation and a writing exercise can boost performance by reducing anxiety and freeing up working memory. If you're worried about doing well in a game or giving a memorized speech in front of others, you instead want to distract yourself so you don't become focused on the details of what you're doing.

Most research into the importance of folate and B12 levels has centered on seniors, and it does seem clear now that having adequate levels of these vitamins is important for maintaining cognitive functioning as you get older. Folic acid levels are of course also regarded as crucial when the brain is developing, which is why pregnant women are urged to take supplements, and why some countries fortify their bread with it. There is less research in the extensive ground between these two end-points.

A Swedish study involving 386 15-year-olds has now found that those in the top third of folic acid intake (more than 253 micrograms per day for girls and 335 for boys) performed significantly better on their school grades compared to those in the bottom third (less than 173 micrograms folic acid per day for girls and 227 for boys).

Interestingly, while homocysteine levels in the blood were initially significant, this association disappeared after other significant predictors (gender, smoking, and SES) were controlled for. Neither was a genotype linked to higher homocysteine levels (MTHFR 677 TT homozygosity) significantly related to academic achievement. Low folate and B12 levels are associated with higher homocysteine levels in the blood, and there is evidence that it is this increase in homocysteine that is the reason for the cognitive impairment seen in age-related cognitive decline. This finding, then, suggests that this is only one part of the story.

Sweden does not fortify flour with folic acid as the United States, Canada and Australia do. Folate is a B vitamin found particularly in citrus fruit, green leafy vegetables, whole-wheat bread, and dried beans and peas; however, they are often destroyed by cooking or processing.

The sum of school grades in 10 core subjects obtained in the final semester of compulsory 9 years of schooling was used as the measure of academic achievement

Following on from research showing that long-term meditation is associated with gray matter increases across the brain, an imaging study involving 27 long-term meditators (average age 52) and 27 controls (matched by age and sex) has revealed pronounced differences in white-matter connectivity between their brains.

The differences reflect white-matter tracts in the meditators’ brains being more numerous, more dense, more myelinated, or more coherent in orientation (unfortunately the technology does not yet allow us to disentangle these) — thus, better able to quickly relay electrical signals.

While the differences were evident among major pathways throughout the brain, the greatest differences were seen within the temporal part of the superior longitudinal fasciculus (bundles of neurons connecting the front and the back of the cerebrum) in the left hemisphere; the corticospinal tract (a collection of axons that travel between the cerebral cortex of the brain and the spinal cord), and the uncinate fasciculus (connecting parts of the limbic system, such as the hippocampus and amygdala, with the frontal cortex) in both hemispheres.

These findings are consistent with the regions in which gray matter increases have been found. For example, the tSLF connects with the caudal area of the temporal lobe, the inferior temporal gyrus, and the superior temporal gyrus; the UNC connects the orbitofrontal cortex with the amygdala and hippocampal gyrus

It’s possible, of course, that those who are drawn to meditation, or who are likely to engage in it long term, have fundamentally different brains from other people. However, it is more likely (and more consistent with research showing the short-term effects of meditation) that the practice of meditation changes the brain.

The precise mechanism whereby meditation might have these effects can only be speculated. However, more broadly, we can say that meditation might induce physical changes in the brain, or it might be protecting against age-related reduction. Most likely of all, perhaps, both processes might be going on, perhaps in different regions or networks.

Regardless of the mechanism, the evidence that meditation has cognitive benefits is steadily accumulating.

The number of years the meditators had practiced ranged from 5 to 46. They reported a number of different meditation styles, including Shamatha, Vipassana and Zazen.

Once upon a time we made a clear difference between emotion and reason. Now increasing evidence points to the necessity of emotion for good reasoning. It’s clear the two are deeply entangled.

Now a new study has found that those with a higher working memory capacity (associated with greater intelligence) are more likely to automatically apply effective emotional regulation strategies when the need arises.

The study follows on from previous research that found that people with a higher working memory capacity suppressed expressions of both negative and positive emotion better than people with lower WMC, and were also better at evaluating emotional stimuli in an unemotional manner, thereby experiencing less emotion in response to those stimuli.

In the new study, participants were given a test, then given either negative or no feedback. A subsequent test, in which participants were asked to rate their familiarity with a list of people and places (some of which were fake), evaluated whether their emotional reaction to the feedback affected their performance.

This negative feedback was quite personal. For example: "your responses indicate that you have a tendency to be egotistical, placing your own needs ahead of the interests of others"; "if you fail to mature emotionally or change your lifestyle, you may have difficulty maintaining these friendships and are likely to form insecure relations."

The false items in the test were there to check for "over claiming" — a reaction well known to make people feel better about themselves and control their reactions to criticism. Among those who received negative feedback, those with higher levels of WMC were found to over claim the most. The people who over claimed the most also reported, at the end of the study, the least negative emotions.

In other words, those with a high WMC were more likely to automatically use an emotion regulation strategy. Other emotional reappraisal strategies include controlling your facial expression or changing negative situations into positive ones. Strategies such as these are often more helpful than suppressing emotion.

Schmeichel, Brandon J.; Demaree, Heath A. 2010. Working memory capacity and spontaneous emotion regulation: High capacity predicts self-enhancement in response to negative feedback. Emotion, 10(5), 739-744.

Schmeichel, Brandon J.; Volokhov, Rachael N.; Demaree, Heath A. 2008. Working memory capacity and the self-regulation of emotional expression and experience. Journal of Personality and Social Psychology, 95(6), 1526-1540. doi: 10.1037/a0013345

A study in which mice were exposed to polluted air for three 5-hour sessions a week for 10 weeks, has revealed that such exposure damaged neurons in the hippocampus and caused inflammation in the brain. The polluted air was laden with particles collected from an urban freeway.

Another recent study found that, of 215 children, those whose cord blood showed high levels of combustion-related pollutants such as polycyclic aromatic hydrocarbons (PAH), had more attention (and anxiety) problems at ages 5 and 7. The children were born to nonsmoking African-American and Dominican women residing in New York City.

A working memory training program developed to help children with ADHD has been tested by 52 students, aged 7 to 17. Between a quarter and a third of the children showed significant improvement in inattention, overall number of ADHD symptoms, initiation, planning/organization, and working memory, according to parental ratings. While teacher ratings were positive, they did not quite reach significance. It is worth noting that this improvement was maintained at the four-month follow-up.

The children used the software in their homes, under the supervision of their parents and the researchers. The program includes a set of 25 exercises in a computer-game format that students had to complete within 5 to 6 weeks. For example, in one exercise a robot will speak numbers in a certain order, and the student has to click on the numbers the robot spoke, on the computer screen, in the opposite order. Each session is 30 to 40 minutes long, and the exercises become progressively harder as the students improve.

The software was developed by a Swedish company called Cogmed in conjunction with the Karolinska Institute. Earlier studies in Sweden have been promising, but this is the first study in the United States, and the first to include children on medication (60% of the participants).

A study involving 48 adolescents, of whom 19 had been diagnosed with substance abuse/dependence, and 14 had a family history of substance abuse but no history of personal use, has found that greater alcohol use was associated with a significant decrease in attention and executive function (which is involved in planning and decision-making), while greater marijuana use was associated with poorer memory. Adolescents in the substance abuse group had lower scores in attention, memory, and processing speed, compared to the other groups, while those with a family history of abuse (but no personal history) had poorer visuospatial ability.

Data from 217 children from Inuit communities in Arctic Quebec (average age 11), of whom some had mothers that reported binge drinking during pregnancy, has revealed that the alcohol-exposed group, while similar to the control in accuracy and reaction time, showed a significant differences in their brains’ electrical activity while doing those tasks (a Go/No-go response inhibition task and a continuous recognition memory task). The differences suggest that fetal alcohol exposure is associated with reduced efficiency in the initial extracting of the meaning of a stimulus, reduced allocation of attention to the task, and poorer conscious recognition memory processing.

A study involving 48 healthy adults aged 18-39 has found that extraverts who were deprived of sleep for 22 hours after spending 12 hours in group activities performed worse on a vigilance task that did those extraverts who engaged in the same activities on their own in a private room. Introverts were relatively unaffected by the degree of prior social interaction.

The researchers suggest that social interactions are cognitively complex experiences that may lead to rapid fatigue in brain regions that regulate attention and alertness, and (more radically) that introverts may have higher levels of cortical arousal, giving them greater resistance to sleep deprivation.

Rupp TL; Killgore WDS; Balkin TJ. Socializing by day may affect performance by night: vulnerability to sleep deprivation is differentially mediated by social exposure in extraverts vs introverts. SLEEP 2010;33(11):1475-1485.

Confirming earlier indications from small studies, a very large nationwide survey has found that people who have had cancer are 40% more likely to experience memory problems that interfere with daily functioning.

The U.S. study involved nearly 10,000 people aged 40 and older, of whom 1,305 (13.3%) reported they had cancer or a history of cancer. Of these, 14% answered yes to the question "Are you limited in any way because of difficulty remembering or because you experience periods of confusion?" Of those who did not have a history of cancer, 8% answered yes to this question.

The degree to which these memory problems are related to the treatment or to the cancer itself (or even perhaps to the experience of having cancer) is one that needs further investigation, but the researcher suggests the finding points to memory issues being more common among cancer sufferers than realized, and recommends that cognitive assessment should be a standard part of cancer treatment.

The study is noteworthy in including all cancers, rather than focusing on one. Nevertheless, I hope that we eventually see a published paper (these results were presented at conference) that also analyses the data in terms of different cancers, different treatments, and length of time since the cancer.

Earlier reports on ‘chemobrain’, and possible ways to help

Results were presented at the Third AACR Conference on The Science of Cancer Health Disparities.

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.

Many survivors of childhood cancer experience cognitive problems as a result of their treatment. The drug methylphenidate (marketed under several names, the best known of which is Ritalin) has previously been shown to help attention problems in such survivors in the short term. Now a new study demonstrates that it can also be of benefit in the long term.

The study tested attention, social skills and behavior in survivors who had been on the drug for a year, comparing them to a similar group of unmedicated survivors. Although the drug did not lead to a significant gain in measured academic skills in math, reading and spelling, many did show improvements to attention that put them back in the normal range.

Nevertheless, the results also emphasize the need for other approaches, given that many did not benefit from the drug, and some may not be good candidates for medical or other reasons. The treatment group included 35 survivors of brain tumors and 33 of acute lymphoblastic leukemia (ALL). Any who suffered from ADHD before their cancer were excluded from the study.

Analysis of DNA and lifestyle data from a representative group of 2,500 U.S. middle- and high-school students tracked from 1994 to 2008 in the National Longitudinal Study of Adolescent Health has revealed that lower academic performance was associated with three dopamine gene variants. Having more of the dopamine gene variants (three rather than one, say) was associated with a significantly lower GPA.

Moreover, each of the dopamine genes (on its own) was linked to specific deficits: there was a marginally significant negative effect on English grades for students with a specific variant in the DAT1 gene, but no apparent effect on math, history or science; a specific variant in the DRD2 gene was correlated with a markedly negative effect on grades in all four subjects; those with the deleterious DRD4 variant had significantly lower grades in English and math, but only marginally lower grades in history and science.

Precisely why these specific genes might impact academic performance isn’t known with any surety, but they have previously been linked to such factors as adolescent delinquency, working memory, intelligence and cognitive abilities, and ADHD, among others.

Five years ago I reported on a finding that primary school children exposed to loud aircraft noise showed impaired reading comprehension (see below). Now a small Norwegian study has found that playing white noise helped secondary school children with attention problems, but significantly impaired those who were normally attentive.

The adolescents were asked to remember as many items as possible from a list read out either in the presence or absence of white noise (78dB). The results were consistent with a computational model based on the concepts of stochastic resonance and dopamine related internal noise, postulating that a moderate amount of external noise would benefit individuals in hypodopaminergic states (such as those with ADHD). The results need to be verified with a larger group, but they do suggest a new approach to helping those with attention problems.

The previous study referred to involved 2844 children aged 9-10. The children were selected from primary schools located near three major airports — Schiphol in the Netherlands, Barajas in Spain, and Heathrow in the UK. Reading age in children exposed to high levels of aircraft noise was delayed by up to 2 months in the UK and by up to 1 month in the Netherlands for each 5 decibel change in noise exposure. On the other hand, road traffic noise did not have an effect on reading and indeed was unexpectedly found to improve recall memory. An earlier German study found children attending schools near the old Munich airport improved their reading scores and cognitive memory performance when the airport shut down, while children going to school near the new airport experienced a decrease in testing scores.

Why are other people’s phone conversations so annoying? A new study suggests that hearing only half a conversation is more distracting than other kinds of conversations because we're missing the other side of the story and so can't predict the flow of the conversation. This finding suggests that driving a car might be impaired not only by the driver talking on the phone, but also by passengers talking on their phones.

It also tells us something about the way we listen to people talking — we’re actively predicting what the person is going to say next. This helps explain something I’ve always wondered about. Listen to people talking in a language you don’t know and you’re often amazed how fast they talk. See an audio recording of the soundwaves, and you’ll wonder how people know when one word starts and another begins. Understanding what people are saying is not as easy as we believe it is — it takes a lot of experience. An important part of that experience, it seems, is learning the patterns of people’s speech, so we can predict what’s going to come next.

The study showed that people overhearing cell phone conversations did more poorly on everyday tasks that demanded attention, than when overhearing both sides of a cell phone conversation, which resulted in no decreased performance. By controlling for other acoustic factors, the researchers demonstrated that it was the unpredictable information content of the half-heard conversation that was so distracting.

Emberson, L.L., Lupyan, G., Goldstein, M.H. & Spivey, M.J. 2010. Overheard Cell-Phone Conversations: When Less Speech Is More Distracting Psychological Science first published on September 3, 2010 as doi:10.1177/0956797610382126

A study following over 300 Mexican-American children living in an agricultural community has found that their prenatal exposure to organophosphate pesticides (measured by metabolites in the mother’s urine during pregnancy) was significantly associated with attention problems at age 5. This association was stronger among boys, and stronger with age (at 3 ½ the association, although present, did not reach statistical significance — perhaps because attention disorders are much harder to recognize in toddlers). Based on maternal report, performance on attention tests, and a psychometrician’s report, 8.5% of 5-year-olds were classified as having ADHD symptoms. Each tenfold increase in prenatal pesticide metabolites was linked to having five times the odds of scoring high on the computerized tests at age 5. The child’s own level of phosphate metabolites was not linked with attention problems.

Organophosphate pesticides disrupt acetylcholine, which is important for attention and short-term memory. While the exposure of these children to pesticides is presumably higher and more chronic than that of the general U.S. population, food is a significant source of pesticide exposure among the general population.

Marks AR, Harley K, Bradman A, Kogut K, Barr DB, Johnson C, et al. 2010. Organophosphate Pesticide Exposure and Attention in Young Mexican-American Children. Environ Health Perspect :-. doi:10.1289/ehp.1002056
Full text available at http://ehp03.niehs.nih.gov/article/fetchArticle.action?articleURI=info%3...

A number of studies have demonstrated that negative stereotypes (such as “women are bad at math”) can impair performance in tests. Now a new study shows that this effect extends to learning. The study involved learning to recognize target Chinese characters among sets of two or four. Women who were reminded of the negative stereotypes involving women's math and visual processing ability failed to improve at this search task, while women who were not reminded of the stereotype got faster with practice. When participants were later asked to choose which of two colored squares, imprinted with irrelevant Chinese characters, was more saturated, those in the control group were slower to respond when one of the characters had been a target. However, those trained under stereotype threat showed no such effect, indicating that they had not learned to automatically attend to a target. It’s suggested that the women in the stereotype threat group tried too hard to overcome the negative stereotype, expending more effort but in an unproductive manner.

There are two problems here, it seems. The first is that people under stereotype threat have more invested in disproving the stereotype, and their efforts may be counterproductive. The second, that they are distracted by the stereotype (which uses up some of their precious working memory).

While studies have demonstrated that listening to music before doing a task can improve performance on that task, chiefly through its effect on mood, there has been little research into the effects of background music while doing the task. A new study had participants recall a list of 8 consonants in a specific order in the presence of five sound environments: quiet, liked music, disliked music, changing-state (a sequence of random digits such as "4, 7, 1, 6") and steady-state ("3, 3, 3"). The most accurate recall occurred when participants performed the task in the quieter, steady-state environments. The level of recall was similar for the changing-state and music backgrounds.

Mind you, this task (recall of random items in order) is probably particularly sensitive to the distracting effects of this sort of acoustical variation in the environment. Different tasks are likely to be differentially affected by background music, and I’d also suggest that the familiarity of the music, and possibly its predictability, also influence its impact. Personally, I am very aware of the effect of music on my concentration, and vary the music, or don’t play at all, depending on what I’m doing and my state of mind. I hope we’ll see more research into these variables.

[1683] Perham N, Vizard J. Can preference for background music mediate the irrelevant sound effect?. Applied Cognitive Psychology [Internet]. 2010 ;9999(9999):n/a - n/a. Available from: http://dx.doi.org/10.1002/acp.1731

Abstract

A review of 35 studies published between 1991 and 2007 has found that depression does not always lead to cognitive impairment. Part of the variability in findings may be due to inconsistent measurement and diagnosis of depression. Processing speed was found to be the cognitive function most consistently affected by depression. Processing speed deficits can be helped by decreasing the amount of information to process at one time.

A study following 1,323 children in Grades 3 to 5 and 210 college students has found that children who exceeded two hours per day of screen time (TV and video games) were 1.5 to two times more likely to be considered above average in attention problems by their teachers compared to children who met the guideline. A similar association between screen media time and attention problems (self-reported) was found for the college students. A study earlier this year found U.S. children aged eight to 18 devote an average of seven hours and 38 minutes per day to entertainment media (http://www.kff.org/entmedia/entmedia012010nr.cfm ).

It’s not just a matter of quantity; quality of sleep matters too. A study involving 72 adults (average age 40), whose sleep was monitored for 11 consecutive nights, has revealed that reaction times on a morning psychomotor vigilance task was significantly slower after exposure to recorded traffic noise during sleep. The slowing was directly related to the frequency and sound-pressure level of the nightly noise. Traffic noise has been identified as one cause of "environmental sleep disorder," which involves an environmental disturbance that causes a complaint of insomnia or daytime sleepiness. Other common causes include bright light and temperature extremes. The researchers also note that nighttime traffic noise may have even stronger effects on the performance of people who are more susceptible to sleep disturbances. Risk groups include children, shift workers, the elderly and people with chronic medical conditions. White noise, produced by fans, sound machines, and special applications for computers and smart phones, can be used to mask other noise.

Elmenhorst, E. et al. 2010. Nocturnal traffic noise and morning cognitive performance. Presented at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC, in San Antonio, Texas.

A study using data on reported homicides in Chicago 1994-2002 and two independent surveys of children and families in Chicago, has revealed that African-American children who were assessed directly after a local homicide occurred scored substantially lower on vocabulary and reading assessments than their peers from the same neighborhood who were assessed at different times. The impact of the homicide faded both with time and distance from the child's home. However, in both datasets, while the results were extremely strong for African Americans, there was no effect of local homicides for Hispanics. Because of the prevalence of homicide in the most violent neighborhoods in cities like Chicago, these results mean that some children spend about one week out of every month functioning at a low level. Whites and other ethnic groups were excluded from the study because they were almost never exposed to local homicides in the samples used.

[1631] Sharkey P. The acute effect of local homicides on children's cognitive performance. Proceedings of the National Academy of Sciences [Internet]. 2010 ;107(26):11733 - 11738. Available from: http://www.pnas.org/content/107/26/11733.abstract

A study involving 379 individuals who abstained from caffeine for 16 hours has revealed little variance in levels of alertness after receiving caffeine. Those who were medium/high caffeine consumers reported a decrease in alertness and an increase in headache if given the placebo, neither of which were reported by those who received caffeine. However, their post-caffeine levels of alertness were no higher than the non/low consumers who received a placebo, suggesting caffeine only brings coffee drinkers back up to 'normal'. In other words, the stimulatory effects of caffeine appears to be an illusion generated by the reversal of the fatiguing effects of acute caffeine withdrawal.

In this study, subjects were shown two sets of 12 color photographs of people’s faces (24 in total). Five minutes after seeing the last one, the subjects were then shown another 48 faces (one by one, as before) and had to say whether or not they had seen the face earlier. If so, they were asked whether they saw it in the first or second set of photographs. Half the subjects had been deprived of sleep for the previous 35 hours. Some of these had been given significant amounts of caffeine to offset their sleepiness.

It was found that the sleep-deprived subjects, whether or not they had had caffeine, were as good as the non-sleep-deprived subjects at recognizing which faces they had seen before. However, the sleep-deprived subjects were significantly worse at remembering which set the faces had appeared in. This occurred even though otherwise optimum conditions for recall existed (the test was novel, stimulating, and relatively short; it was given at the best time of day for maximum alertness).

Caffeine significantly reduced the feelings of sleepiness and did appear to improve the ability of the sleep-deprived subjects to remember which set the face had appeared in, but the level of recall was still significantly below the level of the non-sleep-deprived subjects. Caffeine made no difference to the memory performance of subjects who were not sleep-deprived.

Interestingly, sleep deprivation increased the subjects’ belief that they were right, especially when they were wrong. In this case, whether or not they had had caffeine made no difference.

It may be that the problem with temporal memory reflects a more general problem with remembering context information.

Harrison, Yvonne & Horne, James A. 2000. Sleep loss and temporal memory. The Quarterly Journal of Experimental Psychology, 53A (1), 271-279.

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

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.

 [231] Crego A, Holguín SR, Parada M, Mota N, Corral M, Cadaveira F. Binge drinking affects attentional and visual working memory processing in young university students. Alcoholism, Clinical and Experimental Research [Internet]. 2009 ;33(11):1870 - 1879. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19673739

http://www.eurekalert.org/pub_releases/2009-08/ace-bda080509.php

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.

[1157] Yuen EY, Liu W, Karatsoreos IN, Feng J, McEwen BS, Yan Z. Acute stress enhances glutamatergic transmission in prefrontal cortex and facilitates working memory. Proceedings of the National Academy of Sciences of the United States of America [Internet]. 2009 ;106(33):14075 - 14079. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19666502

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

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.

[200] Scheibe S, Blanchard-Fields F. Effects of regulating emotions on cognitive performance: what is costly for young adults is not so costly for older adults. Psychology and Aging [Internet]. 2009 ;24(1):217 - 223. Available from: http://www.ncbi.nlm.nih.gov/pubmed/19290754

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.

[911] Buzy WM, Medoff DR, Schweitzer JB. Intra-Individual Variability Among Children with ADHD - on a Working Memory Task: An Ex-Gaussian Approach. Child Neuropsychology [Internet]. 2009 ;15(5):441 - 441. Available from: http://www.informaworld.com/10.1080/09297040802646991

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.

[734] Rapport M, Bolden J, Kofler M, Sarver D, Raiker J, Alderson R. Hyperactivity in Boys with Attention-Deficit/Hyperactivity Disorder (ADHD): A Ubiquitous Core Symptom or Manifestation of Working Memory Deficits?. Journal of Abnormal Child Psychology [Internet]. 2009 ;37(4):521 - 534. Available from: http://dx.doi.org/10.1007/s10802-008-9287-8

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.

[461] Evans GW, Schamberg MA. Childhood poverty, chronic stress, and adult working memory. Proceedings of the National Academy of Sciences [Internet]. 2009 ;106(16):6545 - 6549. Available from: http://www.pnas.org/content/early/2009/03/27/0811910106

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

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.

[635] Saxe MD, Malleret G, Vronskaya S, Mendez I, Garcia DA, Sofroniew MV, Kandel ER, Hen R. Paradoxical influence of hippocampal neurogenesis on working memory. Proceedings of the National Academy of Sciences [Internet]. 2007 ;104(11):4642 - 4646. Available from: http://www.pnas.org/content/104/11/4642.abstract

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.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.

[969] Kiefer AK, Sekaquaptewa D. Implicit stereotypes, gender identification, and math-related outcomes: a prospective study of female college students. Psychological Science: A Journal of the American Psychological Society / APS [Internet]. 2007 ;18(1):13 - 18. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17362371

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.

[1082] Cohen GL, Garcia J, Apfel N, Master A. Reducing the Racial Achievement Gap: A Social-Psychological Intervention. Science [Internet]. 2006 ;313(5791):1307 - 1310. Available from: http://www.sciencemag.org/cgi/content/abstract/313/5791/1307

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

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.

[864] Kolachana B, Kleinman JE, Weinberger DR, Meyer-Lindenberg A, Straub RE, Lipska BK, Verchinski BA, Goldberg T, Callicott JH, Egan MF, et al. Genetic evidence implicating DARPP-32 in human frontostriatal structure, function, and cognition. Journal of Clinical Investigation [Internet]. 2007 ;117(3):672 - 682. Available from: http://www.jci.org/articles/view/30413?search%5Babstract_text%5D=&search%5Barticle_text%5D=&search%5Bauthors_text%5D=&search%5Bfpage%5D=672&search%5Bissue%5D=&search%5Btitle_text%5D=&search%5Bvolume%5D=117

http://www.sciencedaily.com/releases/2007/02/070208230059.htm
http://www.eurekalert.org/pub_releases/2007-02/niom-cgv020707.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.

[355] Beilock SL, Carr TH. When high-powered people fail: working memory and "choking under pressure" in math. Psychological Science: A Journal of the American Psychological Society / APS [Internet]. 2005 ;16(2):101 - 105. Available from: http://www.ncbi.nlm.nih.gov/pubmed/15686575

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

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).

[1404] Ramos BP, Birnbaum SG, Lindenmayer I, Newton SS, Duman RS, Arnsten AFT. Dysregulation of protein kinase a signaling in the aged prefrontal cortex: new strategy for treating age-related cognitive decline. Neuron [Internet]. 2003 ;40(4):835 - 845. Available from: http://www.ncbi.nlm.nih.gov/pubmed/14622586

http://www.eurekalert.org/pub_releases/2003-11/naos-mdf110303.php

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.

The findings were presented at the Society for Neuroscience 2003 annual  conference.

http://www.eurekalert.org/pub_releases/2003-11/sfn-sfb_1111003.php

Cognitive impairment following bypass surgery may last longer than thought

More support for a link between cardiopulmonary bypass surgery and cognitive impairment comes from a new study. In particular, it seems, that attention may be most affected. The study also found evidence of longer-lasting cognitive decline than previously thought. Bypass patients also demonstrated poorer cognitive performance before the surgery, and it is now being suggested that it may be the disease itself that is the major problem, rather than the surgery itself. This is consistent with recent research connecting cardiovascular risk factors with risk factors for cognitive decline.

[716] Keith JR, Puente AE, Malcolmson KL, Tartt S, Coleman AE, Marks HF. Assessing postoperative cognitive change after cardiopulmonary bypass surgery. Neuropsychology [Internet]. 2002 ;16(3):411 - 421. Available from: http://www.ncbi.nlm.nih.gov/pubmed/12146688

http://www.eurekalert.org/pub_releases/2002-07/apa-lci070802.php

Cocaine may permanently damage learning abilities in developing fetuses

Two recent studies investigating the effect of pre-natal exposure to cocaine in rats suggest that children exposed to cocaine while in the womb may have permanent changes to the part of the brain that helps control attention and memory, leading to learning deficits and symptoms that are very much like attention deficit hyperactivity disorder.

[1270] Morrow BA, Elsworth JD, Roth RH. Male rats exposed to cocaine in utero demonstrate elevated expression of Fos in the prefrontal cortex in response to environment. Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology [Internet]. 2002 ;26(3):275 - 285. Available from: http://www.ncbi.nlm.nih.gov/pubmed/11850142

[264] Morrow BA, Elsworth JD, Roth RH. Prenatal cocaine exposure disrupts non-spatial, short-term memory in adolescent and adult male rats. Behavioural Brain Research [Internet]. 2002 ;129(1-2):217 - 223. Available from: http://www.sciencedirect.com/science/article/B6SYP-44Y08TP-X/2/053aad67fb4b07c0b8909206a6155b08

http://www.eurekalert.org/pub_releases/2002-02/yu-ucd021802.php