intelligence

Fluctuating sense of control linked to cognitive ability in older adults

April, 2012

A small study has found that, in older adults, their sense of control fluctuates over the course of a day, and this affects their cognitive abilities.

Previous research has pointed to a typical decline in our sense of control as we get older. Maintaining a sense of control, however, appears to be a key factor in successful aging. Unsurprisingly, in view of the evidence that self-belief and metacognitive understanding are important for cognitive performance, a stronger sense of control is associated with better cognitive performance. (By metacognitive understanding I mean the knowledge that cognitive performance is malleable, not fixed, and strategies and training are effective in improving cognition.)

In an intriguing new study, 36 older adults (aged 61-87, average age 74) had their cognitive performance and their sense of control assessed every 12 hours for 60 days. Participants were asked questions about whether they felt in control of their lives and whether they felt able to achieve goals they set for themselves.

The reason I say this is intriguing is that it’s generally assumed that a person’s sense of control — how much they feel in control of their lives — is reasonably stable. While, as I said, it can change over the course of a lifetime, until recently we didn’t think that it could fluctuate significantly in the course of a single day — which is what this study found.

Moreover, those who normally reported having a low sense of control performed much better on inductive reasoning tests during periods when they reported feeling a higher sense of control. Similarly, those who normally reported feeling a high sense of control scored higher on memory tests when feeling more in control than usual.

Although we can’t be sure (since this wasn’t directly investigated), the analysis suggests that the improved cognitive functioning stems from the feeling of improved control, not vice versa.

The study builds on an earlier study that found weekly variability in older adults’ locus of control and competency beliefs.

Assessment was carried out in the form of a daily workbook, containing a number of measures, which participants completed twice daily. Each assessment took around 30-45 minutes to complete. The measures included three cognitive tests (14 alternate forms of each of these were used, to minimize test familiarity):

Letter series test: 30 items in which the next letter in a series had to be identified. [Inductive reasoning]
Number comparison: 48 items in which two number strings were presented beside each other, and participants had to identify where there was any mismatch. [Perceptual speed]
Rey Auditory Verbal Learning Task: participants have to study a list of 15 unrelated words for one minute, then on another page recall as many of the words as they could. [Memory]

Sense of control over the previous 12 hours was assessed by 8 questions, to which participants indicated their agreement/disagreement on a 6-point scale. Half the questions related to ‘locus of control’ and half to ‘perceived competence’.

While, unsurprisingly, compliance wasn’t perfect (it’s quite an arduous regime), participants completed on average 115 of 120 workbooks. Of the possible 4,320 results (36 x 120), only 166 were missing.

One of the things that often annoys me is the subsuming of all within-individual variability in cognitive scores into averages. Of course averages are vital, but so is variability, and this too often is glossed over. This study is, of course, all about variability, so I was very pleased to see people’s cognitive variability spelled out.

Most of the variance in locus of control was of course between people (86%), but 14% was within-individual. Similarly, the figures for perceived competence were 88% and 12%. (While locus of control and perceived competence are related, only 26% of the variability in within-person locus of control was associated with competence, meaning that they are largely independent.)

By comparison, within-individual variability was much greater for the cognitive measures: for the letter series (inductive reasoning), 32% was within-individual and 68% between-individual; for the number matching (perceptual speed), 21% was within-individual and 79% between-individual; for the memory test, an astounding 44% was within-individual and 56% between-individual.

Some of this within-individual variability in cognitive performance comes down to practice effects, which were significant for all cognitive measures. For the memory test, time of day was also significant, with performance being better in the morning. For the letter and number series tests, previous performance also had a small effect on perceived competence. For the number matching, increase in competence subsequent to increased performance was greatest for those with lower scores. However, lagged analyses indicated that beliefs preceded performance to a greater extent than performance preceding beliefs.

While it wasn’t an aspect of this study, it should also be noted that a person’s sense of control may well vary according to domain (e.g., cognition, social interaction, health) and context. In this regard, it’s interesting to note the present findings that sense of control affected inductive reasoning for low-control individuals, but memory for high-control individuals, suggesting that the cognitive domain also matters.

Now this small study was a preliminary one and there are several limitations that need to be tightened up in subsequent research, but I think it’s important for three reasons:

as a demonstration that cognitive performance is not a fixed attribute;
as a demonstration of the various factors that can affect older adults’ cognitive performance;
as a demonstration that your beliefs about yourself are a factor in your cognitive performance.

Reference:

[2794] Neupert, S. D., & Allaire J. C.
(2012). I think I can, I think I can: Examining the within-person coupling of control beliefs and cognition in older adults.
Psychology and Aging. No Pagination Specified - No Pagination Specified.

Source:

http://www.eurekalert.org/pub_releases/2012-02/ncsu-ioa021312.php

Topics:

Aging

tags development:

seniors

tags memworks:

tags problems:

tags strategies:

metamemory

Group settings hurt expressions of intelligence, especially in women

March, 2012

Comparing performance on an IQ test when it is given under normal conditions and when it is given in a group situation reveals that IQ drops in a group setting, and for some (mostly women) it drops dramatically.

This is another demonstration of stereotype threat, which is also a nice demonstration of the contextual nature of intelligence. The study involved 70 volunteers (average age 25; range 18-49), who were put in groups of 5. Participants were given a baseline IQ test, on which they were given no feedback. The group then participated in a group IQ test, in which 92 multi-choice questions were presented on a monitor (both individual and group tests were taken from Cattell’s culture fair intelligence test). Each question appeared to each person at the same time, for a pre-determined time. After each question, they were provided with feedback in the form of their own relative rank within the group, and the rank of one other group member. Ranking was based on performance on the last 10 questions. Two of each group had their brain activity monitored.

Here’s the remarkable thing. If you gather together individuals on the basis of similar baseline IQ, then you can watch their IQ diverge over the course of the group IQ task, with some dropping dramatically (e.g., 17 points from a mean IQ of 126). Moreover, even those little affected still dropped some (8 points from a mean IQ of 126).

Data from the 27 brain scans (one had to be omitted for technical reasons) suggest that everyone was initially hindered by the group setting, but ‘high performers’ (those who ended up scoring above the median) managed to largely recover, while ‘low performers’ (those who ended up scoring below the median) never did.

Personality tests carried out after the group task found no significant personality differences between high and low performers, but gender was a significant variable: 10/13 high performers were male, while 11/14 low performers were female (remember, there was no difference in baseline IQ — this is not a case of men being smarter!).

There were significant differences between the high and low performers in activity in the amygdala and the right lateral prefrontal cortex. Specifically, all participants had an initial increase in amygdala activation and diminished activity in the prefrontal cortex, but by the end of the task, the high-performing group showed decreased amygdala activation and increased prefrontal cortex activation, while the low performers didn’t change. This may reflect the high performers’ greater ability to reduce their anxiety. Activity in the nucleus accumbens was similar in both groups, and consistent with the idea that the students had expectations about the relative ranking they were about to receive.

It should be pointed out that the specific feedback given — the relative ranking — was not a factor. What’s important is that it was being given at all, and the high performers were those who became less anxious as time went on, regardless of their specific ranking.

There are three big lessons here. One is that social pressure significantly depresses talent (meetings make you stupid?), and this seems to be worse when individuals perceive themselves to have a lower social rank. The second is that our ability to regulate our emotions is important, and something we should put more energy into. And the third is that we’ve got to shake ourselves loose from the idea that IQ is something we can measure in isolation. Social context matters.

Reference:

[2730] Kishida, K. T., Yang D., Quartz K H., Quartz S. R., & Montague R. P.
(2012). Implicit signals in small group settings and their impact on the expression of cognitive capacity and associated brain responses.
Philosophical Transactions of the Royal Society B: Biological Sciences. 367(1589), 704 - 716.

Full text available at http://rstb.royalsocietypublishing.org/content/367/1589/704.abstract?sid...

Source:

http://medicalxpress.com/news/2012-01-group-diminish-intelligence-women.... http://www.guardian.co.uk/science/shortcuts/2012/feb/28/warning-meetings-iq

Topics:

Strategies

tags memworks:

tags strategies:

problem solving

How early environment impacts cognitive development

February, 2012

Follow-up on an early child-care program for low-income children finds long-term benefits for education and employment. A large study pinpoints the advantages children from higher-income families have over those from low-middle families. Norway shows how extending compulsory education is linked to higher IQ.

Benefits of high quality child care persist 30 years later

Back in the 1970s, some 111 infants from low-income families, of whom 98% were African-American, took part in an early childhood education program called the Abecedarian Project. From infancy until they entered kindergarten, the children attended a full-time child care facility that operated year-round. The program provided educational activities designed to support their language, cognitive, social and emotional development.

The latest data from that project, following up the participants at age 30, has found that these people had significantly more years of education than peers who were part of a control group (13.5 years vs 12.3), and were four times more likely to have earned college degrees (23% vs 6%).

They were also significantly more likely to have been consistently employed (75% had worked full time for at least 16 of the previous 24 months, compared to 53% of the control group) and less likely to have used public assistance (only 4% received benefits for at least 10% of the previous seven years, compared to 20% of the control group). However, income-to-needs ratios (income taken into account household size) didn’t vary significantly between the groups (mainly because of the wide variability; on the face of it, the means are very different, but the standard deviation is huge), and neither did criminal involvement (27% vs 28%).

See their website for more about this project.

Evidence that more time at school raises IQ

It would be interesting to see what the IQs of those groups are, particularly given that maternal IQ was around 85 for both treatment and control groups. A recent report analyzed the results of a natural experiment that occurred in Norway when compulsory schooling was increased from seven to nine years in the 1960s, meaning that students couldn’t leave until 16 rather than 14. Because all men eligible for the draft were given an IQ test at age 19, statisticians were able to look back and see what effect the increased schooling had on IQ.

They found that it had a substantial effect, with each additional year raising the average IQ by 3.7 points.

While we can’t be sure how far these results extend to other circumstances, they are clear evidence that it is possible to improve IQ through education.

Why children of higher-income parents start school with an advantage

Of course the driving idea behind improved child-care in the early years is all about the importance of getting off to a good start, and you’d expect that providing such care to children would have a greater long-term effect on IQ than simply extending time at school. Most such interventions have looked at the most deprived strata of society. An overlooked area is that of low to middle income families, who are far from having the risk factors of less fortunate families.

A British study involving 15,000 five-year-olds has found that, at the start of school, children from low to middle income families are five months behind children from higher income families in terms of vocabulary skills and have more behavior problems (they were also 8 months ahead of their lowest income peers in vocabulary).

Low-middle income (LMI) households are defined by the Resolution Foundation (who funded this research) as members of the working-age population in income deciles 2-5 who receive less than one-fifth of their gross household income from means-tested benefits (see their website for more detail on this).

Now the difference in home environment between LMI and higher income households is often not that great — particularly when you consider that it is often a difference rooted in timing. LMI households are more common in this group of families with children under five, because the parents are usually at an early stage of life. So what brings about this measurable difference in language and behavior development?

This is a tricky thing to derive from the data, and the findings must be taken with a grain of salt. And as always, interpretation is even trickier. But with this caveat, let’s see what we have. Let’s look at demographics first.

The first thing is the importance of parental education. Income plus education accounted for some 70-80% of the differences in development, with education more important for language development and income more important for behavior development. Maternal age then accounted for a further 10%. Parents in the higher-income group tended to be older and have better education (e.g., 18% of LMI mothers were under 25 at the child’s birth, compared to 6% of higher-income mothers; 30% of LMI parents had a degree compared to 67% of higher-income parents).

Interestingly, family size was equally important for language development (10%), but much less important for behavior development (in fact this was a little better in larger families). Differences in ethnicity, language, or immigration status accounted for only a small fraction of the vocabulary gap, and none of the behavior gap.

Now for the more interesting but much trickier analysis of environmental variables. The most important factor was home learning environment, accounting for around 20% of the difference. Here the researchers point to higher-income parents providing more stimulation. For example, higher-income parents were more likely to read to their 3-year-olds every day (75% vs 62%; 48% for the lowest-income group), to take them to the library at least once a month (42% vs 35% vs 26%), to take their 5-year-old to a play or concert (86% vs 75% vs 60%), to a museum/gallery (67% vs 48% vs 36%), to a sporting activity at least once a week (76% vs 57% vs 35%). Higher-income parents were also much less likely to allow their 3-year-olds to watch more than 3 hours of TV a day (7% vs 17% vs 25%). (I know the thrust of this research is the comparison between LMI and higher income, but I’ve thrown in the lowest-income figures to help provide context.)

Interestingly, the most important factor for vocabulary learning was being taken to a museum/gallery at age 5 (but remember, these correlations could go either way: it might well be that parents are more likely to take an articulate 5-year-old to such a place), with the second most important factor being reading to 3-year-old every day. These two factors accounted for most of the effects of home environment. For behavior, the most important factor was regular sport, followed by being to a play/concert, and being taken to a museum/gallery. Watching more than 3 hours of TV at age 3 did have a significant effect on both vocabulary and behavior development (a negative effect on vocabulary and a positive effect on behavior), while the same amount of TV at age 5 did not.

Differences in parenting style explained 10% of the vocabulary gap and 14% of the behavior gap, although such differences were generally small. The biggest contributors to the vocabulary gap were mother-child interaction score at age 3 and regular bedtimes at age 3. The biggest contributors to the behavior gap were regular bedtimes at age 5, regular mealtimes at age 3, child smacked at least once a month at age 5 (this factor also had a small but significant negative effect on vocabulary), and child put in timeout at least once a month at age 5.

Maternal well-being accounted for over a quarter of the behavior gap, but only a small proportion of the vocabulary gap (2% — almost all of this relates to social support score at 9 months). Half of the maternal well-being component of the behavior gap was down to psychological distress at age 5 (very much larger than the effect of psychological distress at age 3). Similarly, child and maternal health were important for behavior (18% in total), but not for vocabulary.

Material possessions, on the other hand, accounted for some 9% of the vocabulary gap, but none of the behavior gap. The most important factors here were no internet at home at age 5 (22% of LMIs vs 8% of higher-incomes), and no access to a car at age 3 (5% of LMIs had no car vs 1% of higher incomes).

As I’ve intimated, it’s hard to believe we can disentangle individual variables in the environment in an observational study, but the researchers believe the number of variables in the mix (158) and the different time points (many variables are assessed at two or more points) provided a good base for analysis.

Reference:

[2676] Campbell, F. A., Pungello E. P., Burchinal M., Kainz K., Pan Y., Wasik B. H., et al.
(2012). Adult outcomes as a function of an early childhood educational program: An Abecedarian Project follow-up.
Developmental Psychology;Developmental Psychology. No Pagination Specified - No Pagination Specified.

[2675] Brinch, C. N., & Galloway T A.
(2012). Schooling in adolescence raises IQ scores.
Proceedings of the National Academy of Sciences. 109(2), 425 - 430.

Washbrook, E., & Waldfogel, J. (2011). On your marks : Measuring the school readiness of children in low-to-middle income families. Resolution Foundation, December 2011.

Source:

http://medicalxpress.com/news/2012-01-benefits-high-quality-child-persis... http://www.bbc.co.uk/news/health-16320306 http://www.independent.co.uk/news/education/education-news/headstart-at-...

Topics:

Children

tags development:

tags memworks:

tags strategies:

Childrens learning

Genes

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

‘Memory gene’ impacts driving performance

People with a particular variant (“met”) of the COMT gene performed more than 20% worse on a driving test than people without it. About 30% of Americans have the variant, which limits the availability of the vital protein BDNF during activity. Previous studies have shown that in people with the variant, episodic (event) memory is poorer, and a smaller portion of the brain is stimulated when doing a task. The study involved 29 people, of whom 7 had the gene variant, driving 15 laps on a simulator that required them to learn the nuances of a track programmed to have difficult curves and turns. The test was repeated 4 days later. Those with the variant did worse on both tests than the other participants, and they remembered less the second time. However, the gene isn’t all bad — although carriers don't recover as well after a stroke, they retain their mental sharpness longer in the case of neurodegenerative disease.

[1283] McHughen, S. A., Rodriguez P. F., Kleim J. A., Kleim E. D., Crespo L M., Procaccio V., et al.
(2010). BDNF Val66Met Polymorphism Influences Motor System Function in the Human Brain.
Cereb. Cortex. 20(5), 1254 - 1262.

http://www.sciencedaily.com/releases/2009/10/091028134637.htm
http://www.miller-mccune.com/news/are-you-a-bad-driver-it-may-not-be-your-fault-1577
http://www.eurekalert.org/pub_releases/2009-10/uoc--bdm102809.php

Two studies help explain the spacing effect

I talked about the spacing effect in my last newsletter. Now it seems we can point to the neurology that produces it. Not only that, but the study has found a way of modifying it, to improve learning. It’s a protein called SHP-2 phosphatase that controls the spacing effect by determining how long resting intervals between learning sessions need to last so that long-lasting memories can form. The discovery happened because more than 50% of those with a learning disorder called Noonan's disease have mutations in a gene called PTP11, which encodes the SHP-2 phosphatase protein. These mutations boost the activity levels of SHP-2 phosphatase, which, in genetically modified fruit flies, disturbs the spacing effect by increasing the interval before a new chemical signal can occur (it is the repeated formation and decay of these signals that produces memory). Accordingly, those with the mutation need longer periods between repetitions to establish long-term memory.

[1433] Pagani, M. R., Oishi K., Gelb B. D., & Zhong Y.
(2009). The Phosphatase SHP2 Regulates the Spacing Effect for Long-Term Memory Induction.
Cell. 139(1), 186 - 198.

http://www.eurekalert.org/pub_releases/2009-10/cshl-csi092809.php

A study involving Aplysia (often used as a model for learning because of its simplicity and the large size of its neural connections) reveals that spaced and massed training lead to different types of memory formation. The changes at the synapses that underlie learning are controlled by the release of the neurotransmitter serotonin. Four to five spaced applications of serotonin generated long-term changes in the strength of the synapse and less activation of the enzyme Protein kinase C Apl II, leading to stronger connections between neurons. However, when the application of serotonin was continuous (as in massed learning), there was much more activation of PKC Apl II, suggesting that activation of this enzyme may block the mechanisms for generating long-term memory, while retaining mechanisms for short-term memory.

[1504] Villareal, G., Li Q., Cai D., Fink A. E., Lim T., Bougie J. K., et al.
(2009). Role of Protein Kinase C in the Induction and Maintenance of Serotonin-Dependent Enhancement of the Glutamate Response in Isolated Siphon Motor Neurons of Aplysia californica.
J. Neurosci.. 29(16), 5100 - 5107.

http://www.eurekalert.org/pub_releases/2009-10/mu-wow100109.php

Smart gene helps brain cells communicate

For the second time, scientists have created a smarter rat by making their brains over-express CaMKII, a protein that acts as a promoter and signaling molecule for the NR2B subunit of the NMDA receptor. Over-expressing the gene lets brain cells communicate a fraction of a second longer. The research indicates that it plays a crucial role in initiating long-term potentiation. The NR2B subunit is more common in juvenile brains; after puberty the NR2A becomes more common. This is one reason why young people tend to learn and remember better — because the NR2B keeps communication between brain cells open maybe just a hundred milliseconds longer than the NR2A. Although this genetic modification is not something that could probably be replicated in humans, it does validate NR2B as a drug target for improving memory in healthy individuals as well as those struggling with Alzheimer's or mild dementia.

[599] Wang, D., Cui Z., Zeng Q., Kuang H., Wang P. L., Tsien J. Z., et al.
(2009). Genetic Enhancement of Memory and Long-Term Potentiation but Not CA1 Long-Term Depression in NR2B Transgenic Rats.
PLoS ONE. 4(10), e7486 - e7486.

Full text at http://dx.plos.org/10.1371/journal.pone.0007486

http://www.eurekalert.org/pub_releases/2009-10/mcog-sr101909.php

Common variation in gene linked to structural changes in the brain

Variations in the regions of the gene MECP2, previously associated with Retts Syndrome, autism, and mental retardation, has been found to be associated with changes in brain structure in both healthy individuals and patients with neurological and psychiatric disorders. The study used data from 289 healthy and psychotic subjects (the TOP study), and 655 healthy and demented patients (mostly Alzheimer's; from the ADNI study). The most significant genetic variation resulted in reduced surface area in the cortex (in particular in the cuneus, fusiform gyrus, pars triangularis), and was specific to males.

[297] Schork, N. J., Andreassen O. A., Dale A. M., Joyner A. H., Roddey J. Cooper, Bloss C. S., et al.
(2009). A common MECP2 haplotype associates with reduced cortical surface area in humans in two independent populations.
Proceedings of the National Academy of Sciences. 106(36), 15483 - 15488.

http://www.eurekalert.org/pub_releases/2009-08/uoc--cvi081709.php
http://www.eurekalert.org/pub_releases/2009-08/sri-sru081809.php

Genes more important for IQ as children get older

Data from six studies carried out in the US, the UK, Australia and the Netherlands, involving a total of 11,000 pairs of twins, has revealed that genes become more important for intelligence as we get older. The researchers calculated that genes accounted for some 41% of the variation in intelligence in 9 year olds, rising to 55% in 12 year olds, and 66% in 17 year olds. It was suggested that as they get older, children get better at controlling (or perhaps are allowed to have more control over) their environment, which they do in a way that accentuates their ‘natural’ abilities — bright children feed their abilities; less bright children choose activities and friends that are less challenging.

Haworth, C.M.A. et al. 2009. R Plomin The heritability of general cognitive ability increases linearly from childhood to young adulthood. Molecular Psychiatry, advance online publication 2 June 2009; doi: 10.1038/mp.2009.55

http://www.newscientist.com/article/mg20327174.600-genes-drive-iq-more-as-kids-get-older.html

Early maternal experience can affect memory in her offspring

A study of pre-adolescent mice with a genetically-created defect in memory has found that a mere two weeks exposure to a stimulating environment resulted in a reversal of the memory defect. But most surprisingly, it was also found that this effect was passed on to the next generation, even though they had the same genetic defect and even though they had no such experience themselves, and even when they were reared by other mice (not their mothers). It’s worth emphasizing that the enrichment occurs for the mother long before she’s fertile, yet still benefits her offspring. The finding adds to many recent studies showing that genes are more malleable than we thought.

[1434] Arai, J. A., Li S., Hartley D. M., & Feig L. A.
(2009). Transgenerational Rescue of a Genetic Defect in Long-Term Potentiation and Memory Formation by Juvenile Enrichment.
J. Neurosci.. 29(5), 1496 - 1502.

http://www.physorg.com/news152905156.html
http://www.eurekalert.org/pub_releases/2009-02/rumc-wym020209.php
http://www.eurekalert.org/pub_releases/2009-02/tuhs-dyk012909.php

A gene that influences intelligence

A study involving more than 2000 people from 200 families has found a link between the gene CHRM2, that activates multiple signaling pathways in the brain involved in learning, memory and other higher brain functions, and performance IQ. Researchers found that several variations within the CHRM2 gene (which is on chromosome 7) could be correlated with slight differences in performance IQ scores, which measure a person's visual-motor coordination, logical and sequential reasoning, spatial perception and abstract problem solving skills, and when people had more than one positive variation in the gene, the improvements in performance IQ were cumulative. Intelligence is a complex attribute that results from a combination of many genetic and environmental factors, so don’t interpret this finding to mean we’ve found a gene for intelligence.

[1173] Edenberg, H., Porjesz B., Begleiter H., Hesselbrock V., Goate A., Bierut L., et al.
(2007). Association of CHRM2 with IQ: Converging Evidence for a Gene Influencing Intelligence.
Behavior Genetics. 37(2), 265 - 272.

http://www.eurekalert.org/pub_releases/2007-02/wuso-gag022607.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 J. E., Weinberger D. R., Meyer-Lindenberg A., Straub R. E., Lipska B. K., et al.
(2007). Genetic evidence implicating DARPP-32 in human frontostriatal structure, function, and cognition.
Journal of Clinical Investigation. 117(3), 672 - 682.

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

Genetic cause for word-finding disease

Primary Progressive Aphasia is a little-known form of dementia in which people lose the ability to express themselves and understand speech. People can begin to show symptoms of PPA as early as in their 40's and 50's. A new study has found has discovered a gene mutation in two unrelated families in which nearly all the siblings suffered from PPA. The mutations were not observed in the healthy siblings or in more than 200 controls.

[1164] Hutton, M. L., Graff-Radford N. R., Mesulam M. Marsel, Johnson N., Krefft T. A., Gass J. M., et al.
(2007). Progranulin Mutations in Primary Progressive Aphasia: The PPA1 and PPA3 Families.
Arch Neurol. 64(1), 43 - 47.

http://www.eurekalert.org/pub_releases/2007-01/nu-rdg011507.php

Longevity gene also helps retain cognitive function

The Longevity Genes Project has studied 158 people of Ashkenazi, or Eastern European Jewish, descent who were 95 years of age or older. Those who passed a common test of mental function were two to three times more likely to have a common variant of a gene associated with longevity (the CETP gene) than those who did not. When the researchers studied another 124 Ashkenazi Jews between 75 and 85 years of age, those subjects who passed the test of mental function were five times more likely to have this gene variant than their counterparts. The gene variant makes cholesterol particles in the blood larger than normal.

[916] Barzilai, N., Atzmon G., Derby C. A., Bauman J. M., & Lipton R. B.
(2006). A genotype of exceptional longevity is associated with preservation of cognitive function.
Neurology. 67(12), 2170 - 2175.

http://tinyurl.com/yrf5s4
http://www.eurekalert.org/pub_releases/2006-12/aaon-lga121906.php

'Memory gene' identified

Analysis of the human genome has revealed a gene associated with memory performance. The gene is called Kibra, and is expressed in the hippocampus. According to brain scans, people with the version of the gene related to poorer memory potential had to tax their brains harder to remember the same amount of information.

[2658] Papassotiropoulos, A., Stephan D. A., Huentelman M. J., Hoerndli F. J., Craig D. W., Pearson J. V., et al.
(2006). Common Kibra Alleles Are Associated with Human Memory Performance.
Science. 314(5798), 475 - 478.

http://www.eurekalert.org/pub_releases/2006-10/ttgr-rti101906.php

Protein found to inhibit conversion to long-term memory

In a study using genetically engineered mice, researchers have found that mice without a protein called GCN2 acquire new information that doesn’t fade as easily as it does in normal mice. After weak training on the Morris water maze, their spatial memory was enhanced, but it was impaired after more intense training. The researchers concluded that GCN2 may prevent new information from being stored in long-term memory, suggesting the conversion of new information into long-term memory requires both the activation of molecules that facilitate memory storage, and the silencing of proteins such as GCN2 that inhibit memory storage.

[949] Yoshida, M., Imataka H., Cuello C. A., Seidah N., Sossin W., Lacaille J-C., et al.
(2005). Translational control of hippocampal synaptic plasticity and memory by the eIF2[alpha] kinase GCN2.
Nature. 436(7054), 1166 - 1173.

http://www.eurekalert.org/pub_releases/2005-08/uom-mrp082905.php

Closing in on the genes involved in human intelligence

A genetic study claims to have identified two regions of the human genome that appear to explain variation in IQ. Previous research has suggested that between 40% and 80% of variation in human intelligence (as measured by IQ tests) can be attributed to genetic factors, but research has so far failed to identify these genes. The new study has identified specific locations on Chromosomes 2 and 6 as being highly influential in determining IQ, using data from 634 sibling pairs. The region on Chromosome 2 that shows significant links to performance IQ overlaps a region associated with autism. The region on Chromosome 6 that showed strong links with both full-scale and verbal IQ marginally overlapped a region implicated in reading disability and dyslexia.

[382] Posthuma, D., Luciano M., Geus E., Wright M., Slagboom P., Montgomery G., et al.
(2005). A Genomewide Scan for Intelligence Identifies Quantitative Trait Loci on 2q and 6p.
The American Journal of Human Genetics. 77(2), 318 - 326.

http://www.qimr.edu.au/news/index.html

Human cerebellum and cortex age in very different ways

Analysis of gene expression in five different regions of the brain's cortex has found that brain changes with aging were pronounced and consistent across the cortex, but changes in gene expression in the cerebellum were smaller and less coordinated. Researchers were surprised both by the homogeneity of aging within the cortex and by the dramatic differences between cortex and cerebellum. They also found that chimpanzees' brains age very differently from human brains; the findings cast doubt on the effectiveness of using rodents to model various types of neurodegenerative disease.

[951] Fraser, H. B., Khaitovich P., Plotkin J. B., Pääbo S., & Eisen M. B.
(2005). Aging and Gene Expression in the Primate Brain.
PLoS Biol. 3(9), e274 - e274.

http://www.eurekalert.org/pub_releases/2005-08/hu-hca072805.php

More light on a common developmental disorder

Chromosome 22q11.2 deletion syndrome is the most common genetic deletion syndrome, and causes symptoms such as heart defects, cleft palate, abnormal immune responses and cognitive impairments. Two related studies have recently cast more light on these cognitive impairments. Previously it was known that numerical abilities were impaired more than verbal skills. The new study found children with the chromosome deletion performed more poorly on experiments designed to test visual attention orienting, enumerating, and judging numerical magnitudes. All three tasks relate to how the children mentally represent objects and the spatial relationships among them, supporting previous arguments that such visual-spatial skills are a fundamental foundation to the later learning of counting and mathematics. The second study found that such children had changes in the shape, size and position of the corpus callosum, the main bridge between the two hemispheres.

[1139] Simon, T. J., Bearden C. E., Mc-Ginn D MD., & Zackai E.
(2005). Visuospatial and Numerical Cognitive Deficits in Children with Chromosome 22Q11.2 Deletion Syndrome.
Cortex. 41(2), 145 - 155.

[812] Simon, T. J., Ding L., Bish J. P., McDonald-McGinn D. M., Zackai E. H., & Gee J.
(2005). Volumetric, connective, and morphologic changes in the brains of children with chromosome 22q11.2 deletion syndrome: an integrative study.
NeuroImage. 25(1), 169 - 180.

http://www.eurekalert.org/pub_releases/2005-03/chop-lbt030205.php

Closing in on the genes involved in context learning

A study involving the worm C. elegans (whose genome has been completely sequenced) has demonstrated that even such simple animals demonstrate memory that is sensitive to context. In the study, the worms were trained in a salt medium to associate a particular smell with starvation. When placed in a different salt medium, the worms didn’t respond to the smell, but showed distaste when experiencing the smell in the context of the salt medium in which they were trained. More importantly, use of this animal has enabled the researchers to identify a genetic mutation that affects this type of memory. The next step will be to identify the specific gene involved in processing environmental cues.

[1072] Law, E., Nuttley W. M., & van der Kooy D.
(2004). Contextual Taste Cues Modulate Olfactory Learning in C. elegans by an Occasion-Setting Mechanism.
Current Biology. 14(14), 1303 - 1308.

http://www.eurekalert.org/pub_releases/2004-07/uot-eil072704.php

Some brains age more rapidly than others

Investigation of the patterns of gene expression in post-mortem brain tissue has revealed two groups of genes with significantly altered expression levels in the brains of older individuals. The most significantly affected were mostly those related to learning and memory. One of the most interesting, and potentially useful, findings, is that patterns of gene expression were quite similar in the brains of younger adults. Very old adults also showed similar patterns, although the similarity was less. But the greatest degree of individual variation occurred in those aged between 40 and 70. Some of these adults showed gene patterns that looked more like the young group, whereas others showed gene patterns that looked more like the old group. It appears that gene changes start around 40 in some people, but not in others. It also appears that those genes that are affected by age are unusually vulnerable to damage from agents such as free radicals and toxins in the environment, suggesting that lifestyle in young adults may play a part in deciding rate and degree of cognitive decline in later years.

[1335] Lu, T., Pan Y., Kao S-Y., Li C., Kohane I., Chan J., et al.
(2004). Gene regulation and DNA damage in the ageing human brain.
Nature. 429(6994), 883 - 891.

http://www.eurekalert.org/pub_releases/2004-06/chb-dgi060204.php

Could memory performance and spatial learning be genetically based?

A new rat study provides evidence that individual differences in some cognitive functions (specifically spatial navigation, in this experiment) may have a genetic basis.

[1267] Ruiz-Opazo, N., & Tonkiss J.
(2004). X-linked loci influence spatial navigation performance in Dahl rats.
Physiological Genomics. 16(3), 329 - 333.

http://www.eurekalert.org/pub_releases/2004-02/aps-cmp020404.php

Gene essential for development of normal brain connections discovered

After birth, learning and experience change the architecture of the brain dramatically. The structure of individual neurons, or nerve cells, changes during learning to accommodate new connections between neurons. Neuroscientists believe these structural changes are initiated when neurons are activated, causing calcium ions to flow into cells and alter the activity of genes. Now the first gene, CREST, known to mediate these changes in the structure of neurons in response to calcium, has been discovered. In the study, it was found that mice lacking this gene didn’t develop normally in response to sensory experience, and their brains, while normal at birth, later showed far less interconnectivity between neurons. The gene produces a protein that, in adult humans, is produced in the hippocampus. It is therefore speculated that the protein may be necessary for learning and memory storage. The discovery of this gene may have implications for certain types of learning disorders in humans.

[915] Aizawa, H., Hu S-C., Bobb K., Balakrishnan K., Ince G., Gurevich I., et al.
(2004). Dendrite development regulated by CREST, a calcium-regulated transcriptional activator.
Science (New York, N.Y.). 303(5655), 197 - 202.

http://www.eurekalert.org/pub_releases/2004-01/uoc--gef010804.php

Brain protein affecting learning and memory discovered

A significant new brain protein has been identified. Cypin is found throughout the body, but in the brain it now appears that it regulates neuron branching in the hippocampus. Such branching is thought to increase when learning occurs, and a reduction in branching is associated with certain neurological diseases. Discovery of this protein opens the possibility of new drug therapies for treating neurological disorders, and perhaps even memory-enhancing drugs.

[696] Akum, B. F., Chen M., Gunderson S. I., Riefler G. M., Scerri-Hansen M. M., & Firestein B. L.
(2004). Cypin regulates dendrite patterning in hippocampal neurons by promoting microtubule assembly.
Nat Neurosci. 7(2), 145 - 152.

http://www.eurekalert.org/pub_releases/2004-01/rtsu-rsd011204.php
http://news.independent.co.uk/world/science_medical/story.jsp?story=482567

Amphetamine helps or hinders cognitive function depending on your genes

Everyone inherits two copies of the catecho-O-methyltransferase (COMT) gene, that codes for the enzyme that metabolizes neurotransmitters like dopamine and norepinephrine. It comes in two common versions. One version, met, contains the amino acid methionine at a point in its chemical sequence where the other version, val, contains a valine. Depending on the mix of variants inherited, a person's COMT genes can be typed met/met, val/val, or val/met. People with the val/val variant appear to have reduced prefrontal dopamine activity and less efficient prefrontal information processing, along with slightly increased risk for schizophrenia. People with val/met have more efficient prefrontal function, and people with met/met the most efficient.
In a recent imaging study, 27 volunteers (10 val/val, 11 val/met, and 6 met/met) performed a variety of cognitive tasks that involved working memory and executive functioning, after taking either amphetamine or a placebo. Since amphetamine boosts dopamine activity in the prefrontal cortex, the researchers predicted that the drug would enable val/val types to boost their low level of dopamine and perform better on cognitive tasks that depend on the prefrontal cortex. On the other hand, those with met/met should be hindered by amphetamine. The study confirmed these predictions - val/val subjects on amphetamine performed comparably to met/met types in normal conditions, while met/met subjects on amphetamine performed worse than subjects with val/val types in normal conditions.
Amphetamines and other drugs that affect prefrontal dopamine systems are used to treat Attention Deficit Hyperactivity Disorder (ADHD), and other psychiatric illnesses, and some people respond better than others to these medications. About 15-20% of individuals in populations of European ancestry have the met/met COMT gene type.

[1292] Mattay, V. S., Goldberg T. E., Fera F., Hariri A. R., Tessitore A., Egan M. F., et al.
(2003). Catechol O-methyltransferase val158-met genotype and individual variation in the brain response to amphetamine.
Proceedings of the National Academy of Sciences of the United States of America. 100(10), 6186 - 6191.

http://www.eurekalert.org/pub_releases/2003-05/niom-gep050703.php

Gene linked to poor episodic memory

Brain derived neurotrophic factor (BDNF) plays a key role in neuron growth and survival and, it now appears, memory. We inherit two copies of the BDNF gene - one from each parent - in either of two versions. Slightly more than a third inherit at least one copy of a version nicknamed "met," which the researchers have now linked to poorer memory. Those who inherit the “met” gene appear significantly worse at remembering events that have happened to them, probably as a result of the gene’s effect on hippocampal function. Most notably, those who had two copies of the “met” gene scored only 40% on a test of episodic (event) memory, while those who had two copies of the other version scored 70%. Other types of memory did not appear to be affected. It is speculated that having the “met” gene might also increase the risk of disorders such as Alzheimer’s and Parkinson's.

[1039] Dean, M., Egan M. F., Kojima M., Callicott J. H., Goldberg T. E., Kolachana B. S., et al.
(2003). The BDNF val66met Polymorphism Affects Activity-Dependent Secretion of BDNF and Human Memory and Hippocampal Function.
Cell. 112(2), 257 - 269.

http://www.nih.gov/news/pr/jan2003/nimh-23.htm
http://www.eurekalert.org/pub_releases/2003-01/niom-hga012203.php
http://news.bbc.co.uk/1/hi/health/2687267.stm

tags memworks:

Intelligence

Read the article on intelligence, and intelligence & working memory

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

Aerobic fitness boosts IQ in teenage boys

Data from the 1.2 million Swedish men born between 1950 and 1976 who enlisted for mandatory military service at the age of 18 has revealed that on every measure of cognitive performance, average test scores increased according to aerobic fitness — but not muscle strength. The link was strongest for logical thinking and verbal comprehension, and the association was restricted to cardiovascular fitness. The results of the study also underline the importance of getting healthier between the ages of 15 and 18 while the brain is still changing — those who improved their cardiovascular health between 15 and 18 showed significantly greater intelligence scores than those who became less healthy over the same time period. Those who were fittest at 18 were also more likely to go to college. Although association doesn’t prove cause, the fact that the association was only with cardiovascular fitness and not strength supports a cardiovascular effect on brain function. Results from over 260,000 full-sibling pairs, over 3,000 sets of twins, and more than 1,400 sets of identical twins, also supports a causal relationship.

[1486] Åberg, M AI., Pedersen N. L., Torén K., Svartengren M., Bäckstrand B., Johnsson T., et al.
(2009). Cardiovascular fitness is associated with cognition in young adulthood.
Proceedings of the National Academy of Sciences. 106(49), 20906 - 20911.

http://www.physorg.com/news179415275.html
http://www.telegraph.co.uk/science/science-news/6692474/Physical-health-leads-to-mental-health.html

Confidence as important as IQ in exam success

I’ve talked repeatedly about the effects of self-belief on memory and cognition. One important area in which this is true is that of academic achievement. Evidence indicates that your perceived abilities matter, just as much? more than? your actual abilities. It has been assumed that self perceived abilities, self-confidence if you will, is a product mainly of nurture. Now a new twin study provides evidence that nurture / environment may only provide half the story; the other half may lie in the genes. The study involved 1966 pairs of identical twins and 1877 pairs of fraternal twins. The next step is to tease out which of these genes are related to IQ and which to personality variables.

[1080] Greven, C. U., Harlaar N., Kovas Y., Chamorro-Premuzic T., & Plomin R.
(2009). More Than Just IQ: School Achievement Is Predicted by Self-Perceived Abilities—But for Genetic Rather Than Environmental Reasons.
Psychological Science. 20(6), 753 - 762.

http://www.newscientist.com/article/dn17187-confidence-as-important-as-iq-in-exam-success.html

Children of older fathers perform less well in intelligence tests during infancy

Reanalysis of a dataset of over 33,000 children born between 1959 and 1965 and tested at 8 months, 4 years, and 7 years, has revealed that the older the father, the more likely the child was to have lower scores on the various tests used to measure the ability to think and reason, including concentration, learning, memory, speaking and reading skills. In contrast, the older the mother, the higher the scores of the child in the cognitive tests.

[1447] Saha, S., Barnett A. G., Foldi C., Burne T. H., Eyles D. W., Buka S. L., et al.
(2009). Advanced Paternal Age Is Associated with Impaired Neurocognitive Outcomes during Infancy and Childhood.
PLoS Med. 6(3), e1000040 - e1000040.

Full text available at http://medicine.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pmed.1000040

http://www.eurekalert.org/pub_releases/2009-03/plos-coo030309.php

Brain-training to improve working memory boosts fluid intelligence

General intelligence is often separated into "fluid" and "crystalline" components, of which fluid intelligence is considered more reflective of “pure” intelligence (for more on this, see my article), and largely resistant to training and learning effects. However, in a new study in which participants were given a series of training exercises designed to improve their working memory, fluid intelligence was found to have significantly improved, with the amount of improvement increasing with time spent training. The small study contradicts decades of research showing that improving on one kind of cognitive task does not improve performance on other kinds, so has been regarded with some skepticism by other researchers. More research is definitely needed, but the memory task did differ from previous studies, engaging executive functions such as those that inhibit irrelevant items, monitor performance, manage two tasks simultaneously, and update memory.

[1183] Jaeggi, S. M., Buschkuehl M., Jonides J., & Perrig W. J.
(2008). From the Cover: Improving fluid intelligence with training on working memory.
Proceedings of the National Academy of Sciences. 105(19), 6829 - 6833.

http://www.physorg.com/news128699895.html
http://www.sciam.com/article.cfm?id=study-shows-brain-power-can-be-bolstered

Effect of schooling on achievement gaps within racial groups

Analysis of data from a national sample (U.S.) of 8,060 students, collected at four points in time, starting in kindergarten and ending in the spring of fifth grade, has found evidence that education has an impact in closing the achievement gap for substantial numbers of children. High-performing groups in reading were found among all races. About 30% of European Americans, 26% of African Americans and 45% of Asian Americans were in high-achieving groups by the spring of fifth grade — these groups included approximately 23% of African American children and 36% of Asian children who caught up with the initial group of high achievers over time. Only around 4% of European American students were in catch-up groups, because a higher percentage of European Americans started kindergarten as high achievers in reading. The situation was different for Hispanic students, however. By the end of fifth grade, just over 5% of Hispanic children were high achievers in reading, while the remainder tested in the middle range. There were no low achievers and no catch-up groups. A different pattern was found in math. Only 17% of European American students were high-achievers in math by the end of fifth grade, including 13% who started kindergarten at a lower achievement level and caught up over time. About 18% of Asian Americans were high-achievers at the end of fifth grade (11% catch-up). Only 0.3% of African Americans were high achievers at the end of fifth grade, and 26% were medium-high achievers. But about 16% of Hispanics were high achievers in math. There were no catch-up groups for either the African Americans or the Hispanics. This suggests that current schooling doesn't have as strong an impact on math achievement as it does in reading.

The study was presented in Washington, D.C. at the 2008 annual meeting of the Society for Research on Educational Effectiveness.

http://www.physorg.com/news123859991.html

Autism non-verbal not unintelligent

New findings suggest that the association of autism with low intelligence is a product of their language difficulties. Testing autistic kids and normal kids on two popular IQ tests — the WISC (which relies heavily on language) and Raven's Progressive Matrices (considered the best test of "fluid intelligence", and a test that doesn't require much language) found that while not a single autistic child scored in the "high intelligence" range of the WISC, a third did on the Raven's. A third of the autistics had WISC scores in the mentally retarded range, but only one in 20 scored that low on the Raven's test. The non-autistic children scored similarly on both tests. The same results occurred when the experiment was run on autistic and normal adults.

[580] Dawson, M., Soulières I., Gernsbacher M A., & Mottron L.
(2007). The level and nature of autistic intelligence.
Psychological Science: A Journal of the American Psychological Society / APS. 18(8), 657 - 662.

http://www.physorg.com/news105376203.html
http://www.eurekalert.org/pub_releases/2007-08/afps-tmo080307.php

Being treated as oldest linked to IQ

The question of whether there is an IQ advantage to being the first-born has long been debated. Now analysis of IQ test results of 241,310 Norwegians drafted into the armed forces between 1967 and 1976 has revealed that the average IQ of first-born men was 103.2 while second-born men averaged 101.2 and third-borns, 100.0. However, second-born men whose older sibling died in infancy scored 102.9, and if both older siblings died young, the third-born score rose to 102.6. This suggests the advantage lies in the social rank in the family and not birth order as such.

[589] Kristensen, P., & Bjerkedal T.
(2007). Explaining the Relation Between Birth Order and Intelligence.
Science. 316(5832), 1717 - 1717.

http://www.nature.com/news/2007/070618/full/070618-14.html

Executive function as important as IQ for math success

A study of 141 preschoolers from low-income homes has found that a child whose IQ and executive functioning were both above average was three times more likely to succeed in math than a child who simply had a high IQ. The parts of executive function that appear to be particularly linked to math ability in preschoolers are working memory and inhibitory control. In this context, working memory may be thought of as the ability to keep information or rules in mind while performing mental tasks. Inhibitory control is the ability to halt automatic impulses and focus on the problem at hand. Inhibitory control was also important for reading ability. The finding offers the hope that training to improve executive function will improve academic performance.

[1256] Blair, C., & Razza R P.
(2007). Relating Effortful Control, Executive Function, and False Belief Understanding to Emerging Math and Literacy Ability in Kindergarten.
Child Development. 78(2), 647 - 663.

http://www.sciam.com/article.cfm?articleID=90377FAE-E7F2-99DF-3A1204FC5F2BF0F7

Students who believe intelligence can be developed perform better

Research with 12-year-olds has found that, although all students began the study with equivalent achievement levels in math, over a two year period, those who believed that intelligence was malleable increasingly did better than those who believed their intelligence was fixed. Another study found that, when students showing declines in their math grades were taught that intelligence could be increased, they reversed their decline and showed significantly higher math grades than others who weren’t taught that.

[1123] Blackwell, L. S., Trzesniewski K. H., & Dweck C S.
(2007). Implicit Theories of Intelligence Predict Achievement across an Adolescent Transition: A Longitudinal Study and an Intervention.
Child Development. 78(1), 246 - 263.

http://www.eurekalert.org/pub_releases/2007-02/sfri-swb013107.php

Implicit stereotypes and gender identification may affect female math performance

Relatedly, 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, A. K., & Sekaquaptewa D.
(2007). 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. 18(1), 13 - 18.

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, G. L., Garcia J., Apfel N., & Master A.
(2006). Reducing the Racial Achievement Gap: A Social-Psychological Intervention.
Science. 313(5791), 1307 - 1310.

Fitness and childhood IQ indicators of cognitive ability in old age

Data from the Scottish Mental Survey of 1932 has revealed that physical fitness contributed more than 3% of the differences in cognitive ability in old age. The study involved 460 men and women, who were tested using the same cognitive test at age 79 that they had undergone at age 11. Physical fitness was defined by time to walk six meters, grip strength and lung function. Childhood IQ was also significantly related to lung function at age 79, perhaps because people with higher intelligence might respond more favorably to health messages about staying fit. But physical fitness was more important for cognitive ability in old age than childhood IQ. People in more professional occupations and with more education also had better fitness and higher cognitive test scores at 79.

[770] Deary, I. J., Whalley L. J., Batty D. G., & Starr J. M.
(2006). Physical fitness and lifetime cognitive change.
Neurology. 67(7), 1195 - 1200.

http://www.eurekalert.org/pub_releases/2006-10/aaon-fac100306.php

Black-white IQ gap has narrowed

Data now available suggests that Black Americans have gained an average of .18 IQ points a year on White Americans from 1972 to 2002 for a total gain of 5.4 IQ points.

[929] Dickens, W. T., & Flynn J. R.
(2006). Black Americans reduce the racial IQ gap: evidence from standardization samples.
Psychological Science: A Journal of the American Psychological Society / APS. 17(10), 913 - 920.

http://www.eurekalert.org/pub_releases/2006-09/afps-big091206.php

Does IQ drop with age or does something else impact intelligence?

As people grow older, their IQ scores drop. But is it really that they lose intelligence? A study has found that if college students had to perform under conditions that mimic the perception deficits many older people have, their IQ scores would also take a drop.

[234] Gilmore, G. C., Spinks R. A., & Thomas C. W.
(2006). Age effects in coding tasks: componential analysis and test of the sensory deficit hypothesis.
Psychology and Aging. 21(1), 7 - 18.

http://www.eurekalert.org/pub_releases/2006-05/cwru-did050106.php

Smarter kids may live longer

A prospective study that recruited 897 individuals who scored 135 or higher on the Stanford-Binet IQ test in 1922 has found that higher IQs were associated with longevity, with the survival advantage leveling off after a childhood IQ of 163. The association was independent of childhood social position (as measured by father’s occupation). The study confirms earlier research suggesting an association between IQ and mortality, and provides the new finding of where the cut-off point (when high IQ no longer brought additional health benefits) appears — the cutoff of 163 was much higher than expected. Suggested reasons for the association (all of which may well be valid) include: greater tendency to adopt healthy habits and avoid bad ones; increased probability of better jobs; better skills for managing their health and the health-care system.

[690] Martin, L. T., & Kubzansky L. D.
(2005). Childhood Cognitive Performance and Risk of Mortality: A Prospective Cohort Study of Gifted Individuals.
Am. J. Epidemiol.. 162(9), 887 - 890.

http://health.yahoo.com/news/126478

Growing up in a chaotic home may impair child's cognitive development

An association between disorganized, noisy and cramped homes and lower childhood intelligence has been observed before, but the reasons for the association have never been clear. Now a study of some 8000 3- and 4-year-old twins has perhaps disentangled the variables, and has found that chaos had an influence on cognitive skills independent of socioeconomic status. The findings also suggest that when the environment is more stressful, intelligence is more likely to be constrained by genes.

[570] Petrill, S. A., Pike A., Price T., & Plomin R.
(Submitted). Chaos in the home and socioeconomic status are associated with cognitive development in early childhood: Environmental mediators identified in a genetic design.
Intelligence. 32(5), 445 - 460.

http://www.newscientist.com/news/news.jsp?id=ns99996323

Early music instruction raises child’s IQ

A new study confirms earlier research supporting the benefits of early music instruction. The study involved 144 children, 6 years old at the start of the study. They were given free weekly voice or piano lessons at the Royal Conservatory of Music. Another group of 6-year-olds was given free training in weekly drama classes, while a fourth group received no extra classes during the study period. Before any classes were given, all the children were tested using the full Weschler intelligence test. At the end of the school year (their first school year), the children were retested. All had an IQ increase of at least 4.3 points on average (a consequence of going to school). Children who took drama lessons scored no higher than those who had no extra lessons, but those who took music lessons scored on average 2.7 points higher than the children who did not take music lessons. Those in the drama group did however show substantial improvement in adaptive social behavior.

[1009] Schellenberg, E. Glenn
(2004). Music lessons enhance IQ.
Psychological Science: A Journal of the American Psychological Society / APS. 15(8), 511 - 514.

http://www.sciencentral.com/articles/view.htm3?article_id=218392326

Knowledge-based IQ test predicts work performance as well as school

A meta-analysis of 127 studies supports the view that the Miller Analogies Test (MAT) — a knowledge-based test used for admissions decisions into U.S. graduate schools as well as in hiring and promotion decisions in the workplace since 1926 — is predictive of performance in both the academic and workplace environments. Specifically, MAT was a valid predictor of seven of the eight measures of graduate student performance, five of the six school-to-work transition performance criteria, and all four of the work performance criteria. MAT is assumed to measure “g”, the oft-debated “general intelligence” factor.

[1109] Kuncel, N. R., Hezlett S. A., & Ones D. S.
(2004). Academic Performance, Career Potential, Creativity, and Job Performance: Can One Construct Predict Them All?.
Journal of Personality and Social Psychology. 86(1), 148 - 161.

Support for "general intelligence" factor

Researchers into intelligence and memory have always concentrated on verbal abilities — for the good reason that they are considerably easier to test. New research suggests that strong visuospatial skills and working memory may be at least as good as verbal skills and working memory as indicators of general intelligence. The study, involving 167 subjects, found a clear relationship between being good at complex visuospatial tasks, and being good at tasks involving the so-called “central executive” (which coordinates tasks, sets goals, etc). The study lends support both to the view that intelligence has both discrete components and a general aspect, and that this “general intelligence” may be related to executive functioning.

[1152] Miyake, A., Friedman N. P., Rettinger D. A., Shah P., & Hegarty M.
(2001). How are visuospatial working memory, executive functioning, and spatial abilities related? A latent-variable analysis.
Journal of Experimental Psychology. General. 130(4), 621 - 640.

http://www.eurekalert.org/pub_releases/2001-12/apa-npo121001.php

tags memworks:

tags strategies:

training

Poverty-related stress affects cognitive ability

November, 2011

Stress in the lives of young children from low-income homes negatively affects their executive function and IQ, and these associations are mediated through parenting behavior and household risk.

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.

Reference:

[2589] Blair, C., Granger D. A., Willoughby M., Mills-Koonce R., Cox M., Greenberg M. T., et al.
(2011). Salivary Cortisol Mediates Effects of Poverty and Parenting on Executive Functions in Early Childhood.
Child Development. no - no.

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., et al.
(2011). Associations with early-life socio-economic position in adult DNA methylation.
International Journal of Epidemiology.

Source:

http://www.physorg.com/news/2011-10-poverty-related-stress-affects-readi... http://medicalxpress.com/news/2011-10-dna-memory-conditions-childhood.html

Topics:

Lifestyle

tags development:

tags lifestyle:

noise

tags memworks:

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attention problems

IQ can rise or fall significantly during adolescence

November, 2011

A small study of adolescents shows marked variability in IQ over a four-year period for many of them. This variability correlated with specific changes in the brain.

IQ has long been considered to be a fixed attribute, stable across our lifetimes. But in recent years, this assumption has come under fire, with evidence of the positive and negative effects education and experiences can have on people’s performance. Now a new (small) study provides a more direct challenge.

In 2004, 33 adolescents (aged 12-16) took IQ tests and had their brains scanned. These tests were repeated four years later. The teenagers varied considerably in their levels of ability (77-135 in 2004; 87-143 in 2008). While the average IQ score remained the same (112; 113), there were significant changes in the two IQ scores for some individuals, with some participants gaining as much as 21 points, and others falling as much as 18 points. Clear change in IQ occurred for a third of the participants, and there was no obvious connection to specific attributes (e.g., low performers didn’t get better while high performers got worse).

These changes in performance correlated with structural changes in the brain. An increase in verbal IQ score correlated with an increase in the density of grey matter in an area of the left motor cortex of the brain that is activated when articulating speech. An increase in non-verbal IQ score correlated with an increase in the density of grey matter in the anterior cerebellum, which is associated with movements of the hand. Changes in verbal IQ and changes in non-verbal IQ were independent.

While I’d really like to see this study repeated with a much larger sample, the findings are entirely consistent with research showing increases in grey matter density in specific brain regions subsequent to specific training. The novel part of this is the correlation with such large changes in IQ.

The findings add to growing evidence that teachers shouldn’t be locked into beliefs about a student’s future academic success on the basis of past performance.

Postscript: I should perhaps clarify that IQ performance at each of these time points was age-normed - this is not a case of children just becoming 'smarter with age'.

Reference:

[2607] Ramsden, S., Richardson F. M., Josse G., Thomas M. S. C., Ellis C., Shakeshaft C., et al.
(2011). Verbal and non-verbal intelligence changes in the teenage brain.
Nature. advance online publication,

Source:

http://medicalxpress.com/news/2011-10-iq-fall-significantly-adolescence-... http://www.guardian.co.uk/science/2011/oct/19/teenagers-iq-scores-adoles...

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Children

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adolescence

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Music training and language skills

November, 2011

A month-long music-based program produced dramatic improvement in preschoolers’ language skills. Another study helps explain why music training helps language skills.

Music-based training 'cartoons' improved preschoolers’ verbal IQ

A study in which 48 preschoolers (aged 4-6) participated in computer-based, cognitive training programs that were projected on a classroom wall and featured colorful, animated cartoon characters delivering the lessons, has found that 90% of those who received music-based training significantly improved their scores on a test of verbal intelligence, while those who received visual art-based training did not.

The music-based training involved a combination of motor, perceptual and cognitive tasks, and included training on rhythm, pitch, melody, voice and basic musical concepts. Visual art training emphasized the development of visuo-spatial skills relating to concepts such as shape, color, line, dimension and perspective. Each group received two one-hour training sessions each day in classroom, over four weeks.

Children’s abilities and brain function were tested before the training and five to 20 days after the end of the programs. While there were no significant changes, in the brain or in performance, in the children who participated in the visual art training, nearly all of those who took the music-based training showed large improvements on a measure of vocabulary knowledge, as well as increased accuracy and reaction time. These correlated with changes in brain function.

The findings add to the growing evidence for the benefits of music training for intellectual development, especially in language.

Musical aptitude relates to reading ability through sensitivity to sound patterns

Another new study points to one reason for the correlation between music training and language acquisition. In the study, 42 children (aged 8-13) were tested on their ability to read and recognize words, as well as their auditory working memory (remembering a sequence of numbers and then being able to quote them in reverse), and musical aptitude (both melody and rhythm). Brain activity was also measured.

It turned out that both music aptitude and literacy were related to the brain’s response to acoustic regularities in speech, as well as auditory working memory and attention. Compared to good readers, poor readers had reduced activity in the auditory brainstem to rhythmic rather than random sounds. Responsiveness to acoustic regularities correlated with both reading ability and musical aptitude. Musical ability (largely driven by performance in rhythm) was also related to reading ability, and auditory working memory to both of these.

It was calculated that music skill, through the functions it shares with reading (brainstem responsiveness to auditory regularities and auditory working memory) accounts for 38% of the difference in reading ability between children.

These findings are consistent with previous findings that auditory working memory is an important component of child literacy, and that positive correlations exist between auditory working memory and musical skill.

Basically what this is saying, is that the auditory brainstem (a subcortical region — that is, below the cerebral cortex, where our ‘higher-order’ functions are carried out) is boosting the experience of predictable speech in better readers. This fine-tuning may reflect stronger top-down control in those with better musical ability and reading skills. While there may be some genetic contribution, previous research makes it clear that musicians’ increased sensitivity to sound patterns is at least partly due to training.

In other words, giving young children music training is a good first step to literacy.

The children were rated as good readers if they scored 110 or above on the Test of Word Reading Efficiency, and poor readers if they scored 90 or below. There were 8 good readers and 21 poor readers. Those 13 who scored in the middle were excluded from group analyses. Good and poor readers didn’t differ in age, gender, maternal education, years of musical training, extent of extracurricular activity, or nonverbal IQ. Only 6 of the 42 children had had at least a year of musical training (of which one was a poor reader, three were average, and two were good).

Auditory brainstem responses were gathered to the speech sound /da/, which was either presented with 100% probability, or randomly interspersed with seven other speech sounds. The children heard these sounds through an earpiece in the right ear, while they listened to the soundtrack of a chosen video with the other ear.

Reference:

[2603] Moreno, S., Bialystok E., Barac R., Schellenberg E. Glenn, Cepeda N. J., & Chau T.
(2011). Short-Term Music Training Enhances Verbal Intelligence and Executive Function.
Psychological Science. 22(11), 1425 - 1433.

Strait, Dana L, Jane Hornickel, and Nina Kraus. “Subcortical processing of speech regularities underlies reading and music aptitude in children.” Behavioral and brain functions : BBF 7, no. 1 (October 17, 2011): 44. http://www.ncbi.nlm.nih.gov/pubmed/22005291.

Full text is available at http://www.behavioralandbrainfunctions.com/content/pdf/1744-9081-7-44.pd...

Source:

http://www.eurekalert.org/pub_releases/2011-10/bcfg-ycs100411.php http://www.eurekalert.org/pub_releases/2011-10/bc-mar101411.php

Topics:

Strategies

tags development:

preschool child

tags memworks:

intelligence

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dyslexia therapy

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reading

Many genes are behind human intelligence

August, 2011

A large-scale genome-wide analysis has confirmed that half the differences in intelligence between people of similar background can be attributed to genetic differences — but it’s an accumulation of hundreds of tiny differences.

There has been a lot of argument over the years concerning the role of genes in intelligence. The debate reflects the emotions involved more than the science. A lot of research has gone on, and it is indubitable that genes play a significant role. Most of the research however has come from studies involving twins and adopted children, so it is indirect evidence of genetic influence.

A new technique has now enabled researchers to directly examine 549,692 single nucleotide polymorphisms (SNPs — places where people have single-letter variations in their DNA) in each of 3511 unrelated people (aged 18-90, but mostly older adults). This analysis had produced an estimate of the size of the genetic contribution to individual differences in intelligence: 40% of the variation in crystallized intelligence and 51% of the variation in fluid intelligence. (See http://www.memory-key.com/memory/individual/wm-intelligence for a discussion of the difference)

The analysis also reveals that there is no ‘smoking gun’. Rather than looking for a handful of genes that govern intelligence, it seems that hundreds if not thousands of genes are involved, each in their own small way. That’s the trouble: each gene makes such a small contribution that no gene can be fingered as critical.

Discussions that involve genetics are always easily misunderstood. It needs to be emphasized that we are talking here about the differences between people. We are not saying that half of your IQ is down to your genes; we are saying that half the difference between you and another person (unrelated but with a similar background and education — study participants came from Scotland, England and Norway — that is, relatively homogenous populations) is due to your genes.

If the comparison was between, for example, a middle-class English person and someone from a poor Indian village, far less of any IQ difference would be due to genes. That is because the effects of environment would be so much greater.

These findings are consistent with the previous research using twins. The most important part of these findings is the confirmation it provides of something that earlier studies have hinted at: no single gene makes a significant contribution to variation in intelligence.

Reference:

[2356] Davies, G., Tenesa A., Payton A., Yang J., Harris S. E., Liewald D., et al.
(2011). Genome-wide association studies establish that human intelligence is highly heritable and polygenic.
Mol Psychiatry.

Source:

http://medicalxpress.com/news/2011-08-reveals-genetic-link-human-intelli...
http://the-scientist.com/2011/08/09/heritability-of-intelligence/
http://www.guardian.co.uk/science/2011/aug/09/genetic-differences-intell...
http://www.edweek.org/ew/articles/2011/08/09/446822_ap.html (registration required)

Topics:

How the brain works

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The right sort of video game can increase your intelligence

June, 2011

Games that use the n-back task, designed to challenge working memory, may improve fluid intelligence, but only if the games are at the right level of difficulty for the individual.

It has been difficult to train individuals in such a way that they improve in general skills rather than the specific ones used in training. However, recently some success has been achieved using what is called an “n-back” task, a task that involves presenting a series of visual and/or auditory cues to a subject and asking the subject to respond if that cue has occurred, to start with, one time back. If the subject scores well, the number of times back is increased each round.

In the latest study, 62 elementary and middle school children completed a month of training on a computer program, five times a week, for 15 minutes at a time. While the active control group trained on a knowledge and vocabulary-based task, the experimental group was given a demanding spatial task in which they were presented with a sequence of images at one of six locations, one at a time, at a rate of 3s. The child had to press one key whenever the current image was at the same location as the one n items back in the series, and another key if it wasn’t. Both tasks employed themed graphics to make the task more appealing and game-like.

How far back the child needed to remember depended on their performance — if they were struggling, n would be decreased; if they were meeting the challenge, n would be increased.

Although the experimental and active control groups showed little difference on abstract reasoning tasks (reflecting fluid intelligence) at the end of the training, when the experimental group was divided into two subgroups on the basis of training gain, the story was different. Those who showed substantial improvement on the training task over the month were significantly better than the others, on the abstract reasoning task. Moreover, this improvement was maintained at follow-up testing three months later.

The key to success seems to be whether or not the games hit the “sweet spot” for the individual — fun and challenging, but not so challenging as to be frustrating. Those who showed the least improvement rated the game as more difficult, while those who improved the most found it challenging but not overwhelming.

You can try this task yourself at http://brainworkshop.sourceforge.net/.

Reference:

Jaeggi, Susanne M, Martin Buschkuehl, John Jonides, and Priti Shah. “Short- and long-term benefits of cognitive training.” Proceedings of the National Academy of Sciences of the United States of America 2011 (June 13, 2011): 2-7. http://www.ncbi.nlm.nih.gov/pubmed/21670271.

Source:

http://www.latimes.com/health/la-he-iq-boost-20110614-1,0,2455553.story http://consumer.healthday.com/Article.asp?AID=653856 http://health.usnews.com/health-news/family-health/brain-and-behavior/ar... http://medicalxpress.com/news/2011-05-brain_1.html

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Strategies

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school-age child

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Video games

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Benefits of high quality child care persist 30 years later

Evidence that more time at school raises IQ

Why children of higher-income parents start school with an advantage

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

‘Memory gene’ impacts driving performance

Two studies help explain the spacing effect

Smart gene helps brain cells communicate

Common variation in gene linked to structural changes in the brain

Genes more important for IQ as children get older

Early maternal experience can affect memory in her offspring

A gene that influences intelligence

Common gene version optimizes thinking but carries a risk

Genetic cause for word-finding disease

Longevity gene also helps retain cognitive function

'Memory gene' identified

Protein found to inhibit conversion to long-term memory

Closing in on the genes involved in human intelligence

Human cerebellum and cortex age in very different ways

More light on a common developmental disorder

Closing in on the genes involved in context learning

Some brains age more rapidly than others

Could memory performance and spatial learning be genetically based?

Gene essential for development of normal brain connections discovered

Brain protein affecting learning and memory discovered

Amphetamine helps or hinders cognitive function depending on your genes

Gene linked to poor episodic memory

tags memworks:

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

Aerobic fitness boosts IQ in teenage boys

Confidence as important as IQ in exam success

Children of older fathers perform less well in intelligence tests during infancy

Brain-training to improve working memory boosts fluid intelligence

Effect of schooling on achievement gaps within racial groups

Autism non-verbal not unintelligent

Being treated as oldest linked to IQ

Executive function as important as IQ for math success

Students who believe intelligence can be developed perform better

Implicit stereotypes and gender identification may affect female math performance

Reducing the racial achievement gap

Fitness and childhood IQ indicators of cognitive ability in old age

Black-white IQ gap has narrowed

Does IQ drop with age or does something else impact intelligence?

Smarter kids may live longer

Growing up in a chaotic home may impair child's cognitive development

Early music instruction raises child’s IQ

Knowledge-based IQ test predicts work performance as well as school

Support for "general intelligence" factor

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Long-term genetic effects of childhood environment

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