2012 April 15 Sunday
Genetic Variant Influences Brain Size, Intelligence

While searching for genetic variants that impact a brain's risks of a variety of mental illnesses researchers have discovered a genetic variant that contributes to intelligence differences.

In the world's largest brain study to date, a team of more than 200 scientists from 100 institutions worldwide collaborated to map the human genes that boost or sabotage the brain's resistance to a variety of mental illnesses and Alzheimer's disease. Published April 15 in the advance online edition of Nature Genetics, the study also uncovers new genes that may explain individual differences in brain size and intelligence.

"We searched for two things in this study," said senior author Paul Thompson, professor of neurology at the David Geffen School of Medicine at UCLA and a member of the UCLA Laboratory of Neuro Imaging. "We hunted for genes that increase your risk for a single disease that your children can inherit. We also looked for factors that cause tissue atrophy and reduce brain size, which is a biological marker for hereditary disorders like schizophrenia, bipolar disorder, depression, Alzheimer's disease and dementia."

This isn't surprising. Since genetic sequencing costs have plunged by orders of magnitude researchers can finally collect enough genetic sequencing data to identify genetic variants that each make a small difference in intelligence. The evidence so far suggests that most intelligence-influencing genes each have only small impact. So large data sets are needed to order to pick up the signal from each genetic variant that has an impact on intelligence.

In an intriguing twist, Project ENIGMA investigators also discovered genes that explain individual differences in intelligence. They found that a variant in a gene called HMGA2 affected brain size as well as a person's intelligence.

DNA is comprised of four bases: A, C, T and G. People whose HMGA2 gene held a letter "C" instead of "T" on that location of the gene possessed larger brains and scored more highly on standardized IQ tests.

"This is a really exciting discovery: that a single letter change leads to a bigger brain," said Thompson. "We found fairly unequivocal proof supporting a genetic link to brain function and intelligence. For the first time, we have watertight evidence of how these genes affect the brain. This supplies us with new leads on how to mediate their impact."

More genetic variants that influence intelligence will be found this year and even more the next year and the following year. By 2020 I expect most of the genes that influence intelligence will be known. Small numbers of people will start doing embryo selection based on intelligence in this decade and large numbers of people will do so in the 2020s.

By Randall Parker    2012 April 15 12:17 PM   Entry Permalink | Comments (21)
2012 April 12 Thursday
Executive Functions Key For Elite Football Players

In the sport called soccer in America and football almost everywhere else high executive brain function is key to elite football player skill.

Measuring what are known as 'executive functions', which reflect the cognitive ability to deal with sudden problems, may make it possible to predict how good an elite football player will become in the future. This has been shown by a new study from Karolinska Institutet. Scientists believe for the first time that they have found the scientific key to what has previously been described as 'game intelligence' in successful football players.

Those with greater ability to read the game and be in the right place have higher executive function.

It has long been known that physical ability and ball sense are not enough to become really good at football. A third vital component has often been mentioned: game intelligence, which is the ability to 'read' the play, to be always in the right place at the right time, and steal goals. Many people have regarded game intelligence to be almost a magical ability, something that is impossible to measure.

The scientists at Karolinska Institutet, however, claim that game intelligence is hardly mystical, and that it can be understood from a scientific perspective. It is, rather, an example of something that cognitive scientists call executive functions, which encompass the ability to be immediately creative, to be able to see new solutions to problems, to change tactics rapidly and to revise previous behaviour that has proved not to work.

Higher division players have higher scores on average for executive function as compared to lower division players and they both had higher function than the population they came from.

Predrag Petrovic and his colleagues report in one study, to be published in the on-line scientific journal PLoS ONE, tests of certain executive functions in football players in Allsvenskan (the highest Swedish league) and in Division 1 (the league under Allsvenskan), a total of 57 elite footballers. The scientists found that football players in both groups performed much better in tests of executive functions than the general population. And they found that players in Allsvenskan achieved much better results in these tests than players in Division 1.

With the great flood of genetic data that has come as a consequence of an orders of magnitude drop in DNA sequencing costs we are probably within at most 5 years of identification of the genetic variations that account for much of the differences in executive function. So I expect in about the same time frame genetic tests for potential to make it as an elite footballer. Ditto for fighter pilots, concert pianists, and other cognitively demanding yet physical occupations.

By Randall Parker    2012 April 12 10:17 PM   Entry Permalink | Comments (4)
Brain Injury Subjects Used To Map General Intelligence

While you can find people who (quite erroneously) deny the importance or existence of general intelligence the research that establishes the existence of Charles Spearman's 'g' is really quite good. In the latest development Vietnam vets who have very localized brain damage were used to the areas of the brain key for enabling general intelligence.

CHAMPAIGN, Ill. — Scientists report that they have mapped the physical architecture of intelligence in the brain. Theirs is one of the largest and most comprehensive analyses so far of the brain structures vital to general intelligence and to specific aspects of intellectual functioning, such as verbal comprehension and working memory.

Their study, published in Brain: A Journal of Neurology, is unique in that it enlisted an extraordinary pool of volunteer participants: 182 Vietnam veterans with highly localized brain damage from penetrating head injuries.

Having patients with very localized damage was key to identifying which parts of the brain are most important for determining general intelligence.

"It's a significant challenge to find patients (for research) who have brain damage, and even further, it's very hard to find patients who have focal brain damage," said University of Illinois neuroscience professor Aron Barbey, who led the study. Brain damage – from stroke, for example – often impairs multiple brain areas, he said, complicating the task of identifying the cognitive contributions of specific brain structures.

But the very focal brain injuries analyzed in the study allowed the researchers "to draw inferences about how specific brain structures are necessary for performance," Barbey said. "By studying how damage to particular brain regions produces specific forms of cognitive impairment, we can map the architecture of the mind, identifying brain structures that are critically important for specific intellectual abilities."

Brain CT scans were essential to identify where general intelligence is located. Turns out to be a fairly small number of areas of the brain.

The researchers took CT scans of the participants' brains and administered an extensive battery of cognitive tests. They pooled the CT data to produce a collective map of the cortex, which they divided into more than 3,000 three-dimensional units called voxels. By analyzing multiple patients with damage to a particular voxel or cluster of voxels and comparing their cognitive abilities with those of patients in whom the same structures were intact, the researchers were able to identify brain regions essential to specific cognitive functions, and those structures that contribute significantly to intelligence.

"We found that general intelligence depends on a remarkably circumscribed neural system," Barbey said. "Several brain regions, and the connections between them, were most important for general intelligence."

Where your general smarts come from:

These structures are located primarily within the left prefrontal cortex (behind the forehead), left temporal cortex (behind the ear) and left parietal cortex (at the top rear of the head) and in "white matter association tracts" that connect them.

What will be interesting: discovery of genes expressed during development in those regions and genetic variations that influence how much those genes get expressed. Note that since neuron generation continues well into adolescence the mutations of interest might be for making the brain grow more rather late in development.

By Randall Parker    2012 April 12 09:51 PM   Entry Permalink | Comments (0)
2011 October 20 Thursday
Genes That Make Human Brain Distinctively Human

Why are humans smarter than other species? About 50 to 60 genes unique to humans are involved in building and operating the frontal cortex of the brain.

Young genes that appeared after the primate branch split off from other mammal species are more likely to be expressed in the developing human brain, a new analysis finds. The correlation suggests that evolutionarily recent genes, which have been largely ignored by scientists thus far, may be responsible for constructing the uniquely powerful human brain. The findings are published October 18 in the online, open access journal PLoS Biology.

"We found that there is a correlation between new gene origination and the evolution of the brain," said senior author Manyuan Long, PhD, Professor of Ecology & Evolution at the University of Chicago. "There are some 50 to 60 human-specific genes in the frontal cortex of the brain, the part that makes humans diverge with other non-human primates."

These genes are good candidates to compare people to identify the genes that cause IQ differences.

Here's the report: Accelerated Recruitment of New Brain Development Genes into the Human Genome

These genes express early in development:

The researchers found that a higher percentage of primate-specific young genes were expressed in the brain compared to mouse-specific young genes. Human-specific young genes also were more likely to be expressed in the recently expanded human brain structures, such as the neocortex and prefrontal cortex.

"Newer genes are found in newer parts of the human brain," said Yong Zhang, PhD, postdoctoral researcher and first author on the study. "We know the brain is the most remarkable difference between humans and other mammals and primates. These new genes are a candidate for future studies, as they are more likely to underlie this difference."

The timing of when the young human-specific genes are expressed in the brain also intrigued the researchers. Inspired by an ultrasound appointment with his pregnant wife, Zhang calculated when young genes were expressed in the human brain, discovering that they were more likely to appear during fetal or infant development.

The early activity of these genes suggests scientists should be looking at earlier developmental stages for genetic activity that ultimately shapes the complexity of the human brain.

These genes probably don't just play a role in boosting IQ. They might make unique human behaviors manifest as well.

By Randall Parker    2011 October 20 06:02 AM   Entry Permalink | Comments (4)
2011 January 24 Monday
Smart People Better Looking

Satoshi Kanazawa of the London School of Economics

The research found handsome men scored 13.6 points above the average IQ score of 100.

And beautiful women were 11.4 points above the norm, according to the London School of Economics.

Since I want the future human race to be more beautiful and much smarter it is great to hear that these goals are very compatible.

So what's the arrow of causation? I can think of a few candidates. First off, an environment and nutrition that enable healthier fetal and baby development will make bodies more symmetric and symmetry is very attractive. At the same time, healthier developmental conditions will enable the brain to grow better. So IQ and beauty might at least partially be the product of good biochemical environment during development.

Another obvious possibility is genes driving both the symmetry and smart brain development. A good combination of genes could improve the whole developmental process at the fetal and later stages.

Still another possibility: modern mating practices. Could be that smarter successful men are going after more beautiful women and so smarts and beauty are being produced in hybrids.

This naturally brings us to the important topic of attractive actresses and models. Finally a FuturePundit-worthy reason to talk about them. "Support for the juxtaposition of beauty and brains is apparent in supermodel Lily Cole and actress Kate Beckinsale both Oxbridge graduates." Jeri Ryan was a National Merit Scholar. Natalie Portman graduated from Harvard and Brooke Shields (Pretty Baby pictures here) from Princeton. I figure the number of Ivy League degrees for beautiful women underestimate their prevalence among the brainy since quite a few brainy beautiful women have other options for advancement. They can make money in modeling and acting. Also, they have better odds of marrying rich.

By Randall Parker    2011 January 24 11:44 PM   Entry Permalink | Comments (14)
2010 December 25 Saturday
Border Collie Chaser Knows 1022 Words

Chaser is a smart girl.

IN THE age-old war between cats and dogs, canines might just have struck the killer blow. A border collie called Chaser has been taught the names of 1022 items - more than any other animal. She can also categorise them according to function and shape, something children learn to do around the age of 3.

Of course it would be a Border Collie. I used to know a Border-Aussie (Australian Shepherd) mix who was so bright that he knew 250 words according to his owner. Given what I saw of that dog I found the claim believable. That a Border could know 1022 words and even understand verbs versus nouns and other details of sentence structure still seems amazing though.

The article above has a video of Chaser demonstrating Border Collie brilliance. You can also watch Chaser perform on this video and this video with more other videos on YouTube. Since Chaser demonstrates understanding of combinations of nouns and verbs she's like a very young human child in terms of her language skills.

My take: Dogs have been bred to have such a large variety of differences in behavior the various breeds that they will make great sources of DNA sequences to use to identify genetic variants that cause their cognitive characteristics. Given that the breeds differ considerably intelligence comparing breeds (or even different dogs in the same breed) could turn out to be useful in identifying genetic variants that cause intelligence and behavioral differences.

Where does this lead? Breeding for even smarter dogs which can understand even more complex forms of human language. Dog DNA sequencing to discover genes that influence intelligence might turn up some intelligence-boosting genetic variants than even Chaser has. Identification of all these variants would give breeders a goal to shoot for: get as many of the variants as possible into the same litter of dogs.

Identification of intelligence-boosting genetic variants in other species could lead to genetic engineering to put some of those variants into dogs. Is a 70+ IQ dog within reach in, say, 20 or 30 years? Seems like it.

By Randall Parker    2010 December 25 07:48 PM   Entry Permalink | Comments (7)
2010 September 05 Sunday
Dopamine Gene Variants Cut Student Performance?

Blame your bad grades on your dopamine gene variants.

The academic performance of adolescents will suffer in at least one of four key subjects –– English, math, science, history –– if their DNA contains one or more of three specific dopamine gene variations, according to a study led by renowned biosocial criminologist Kevin M. Beaver of The Florida State University.

The research sheds new light on the genetic components of academic performance during middle and high school, and on the interplay of specific genes and environmental factors such as peer behavior or school conditions.

They looked at 2,500 kids enrolled in the National Longitudinal Study of Adolescent Health over 14 years to reach this conclusion. Once gene sequencing becomes really cheap imagine what will be discovered if the same 2,500 have their full genomes sequenced and they are given IQ tests as well. We are getting close to when most of the genetic variants that influence IQ will be discovered.

“We believe that dopaminergic genes affect GPA because they have previously been linked to factors associated with academic performance, including adolescent delinquency, working memory, intelligence and cognitive abilities, and ADHD, among others,” Beaver said. “So, the genetic effect would operate indirectly via these other correlates to GPA and school performance.”

What's needed: For a group like these students to be given many tests of cognitive performance and personality.Then do full genome sequencing and genetic testing for large copy variations that sequencing might not catch.

3 different dopamine genes have variants correlated with scholastic performance.

For instance, they found a marginally significant negative effect on English grades for students with a single dopamine variant in a gene known as DAT1, but no apparent effect on math, history or science. In contrast, a variant in the DRD2 gene was correlated with a markedly negative effect on grades in all four subjects. Students with a single, DRD4 variant had significantly lower grades in English and math, but only marginally lower grades in history and science.

In 10 years I predict it will become commonplace for especially ambitious prospective parents to opt for in vitro fertilization (IVF) combined with genetic testing to do embryo selection for most desired genetic characteristics. Why run the risk of giving birth to merely average or even sociopathic criminal kids? Parents will jump at the chance to reduce risks and produce better outcomes.

By Randall Parker    2010 September 05 08:05 PM   Entry Permalink | Comments (3)
2010 February 22 Monday
Brain Genes Key For Facial Recognition

Your ability to recognize faces comes from your genes.

The ability to recognise faces is largely determined by your genes, according to new research at UCL (University College London).

Published today in the Proceedings of the National Academy of Sciences, scientists found that identical twins were twice as similar to each other in terms of their ability to recognise faces, compared to non-identical twins.

Researchers also found that the genetic effects that allow people to recognise faces are linked to a highly specific mechanism in the brain, unrelated to other brain processes such as the ability to recognise words or abstract art.

The researchers used the Cambridge Face Memory Test in this study. You can take the Cambridge Face Memory test online.

It is going to be interesting to see which forms of cognitive ability are not part of the g-factor type of general intelligence. Once genetic trade-offs between different types of cognitive abilities become known prospective parents will face difficult choices. Which types of intellectual ability to favor? Abilities that enhances different types of athletic performance? Abilities that make someone a top lawyer? Or a combination of intellectual abilities, coordination, and stamina that makes for a top surgeon?

By Randall Parker    2010 February 22 11:03 PM   Entry Permalink | Comments (0)
Intelligence Tracked To Brain Regions

Spearman's g-factor comes from a distributed set of brain regions.

PASADENA, Calif.—A collaborative team of neuroscientists at the California Institute of Technology (Caltech), the University of Iowa, the University of Southern California (USC), and the Autonomous University of Madrid have mapped the brain structures that affect general intelligence.

The study, to be published the week of February 22 in the early edition of the Proceedings of the National Academy of Sciences, adds new insight to a highly controversial question: What is intelligence, and how can we measure it?

The research team included Jan Gläscher, first author on the paper and a postdoctoral fellow at Caltech, and Ralph Adolphs, the Bren Professor of Psychology and Neuroscience and professor of biology. The Caltech scientists teamed up with researchers at the University of Iowa and USC to examine a uniquely large data set of 241 brain-lesion patients who all had taken IQ tests. The researchers mapped the location of each patient's lesion in their brains, and correlated that with each patient's IQ score to produce a map of the brain regions that influence intelligence.

Of course, if IQ differences can be traced down to physical differences in brain regions then IQ is a product of physical qualities of brains.

Connections between the brain regions matter too.

"One of the main findings that really struck us was that there was a distributed system here. Several brain regions, and the connections between them, were what was most important to general intelligence," explains Gläscher.

Once the genetic causes of intelligence differences become known and DNA testing becomes ultra-cheap the dating and mating game will change quite drastically. Equally intelligent people won't have equal odds at making smart babies because some will have some IQ-boosting genes on only one out of a chromosome pair and others will have the boosting genes on both chromosomes. The latter will make the most attractive mates for those who want smart babies. Also, in vitro fertlization with genetic testing to select embryos will become the rage for those most ambitious about their children.

By Randall Parker    2010 February 22 10:34 PM   Entry Permalink | Comments (14)
2007 October 16 Tuesday
Twin Brain Scan Studies Find Genetic Influences On Intelligence

Evidence suggests that lots of genetic variations that influence intelligence are waiting to be found.

Evidence is accumulating that brain structure is under considerable genetic influence [Peper et al., 2007]. Puberty, the transitional phase from childhood into adulthood, involves changes in brain morphology that may be essential to optimal adult functioning. Around the onset of puberty gray matter volume starts to decrease, while white matter volume is still increasing [Giedd et al., 1999].

Recent findings have shown, that variation in total gray and white matter volume of the adult human brain is primarily (70–90%) genetically determined [Baare et al, 2001] and in a recent magnetic resonance imaging (MRI) brain study with 45 monozygotic and 61 dizygotic 9-year-old twin-pairs, and their 87 full siblings also high heritabilities have been found [Peper et al, in preparation]. Thus, while environmental influences may play a role in later stages during puberty, around the onset of puberty brain volumes are already highly heritable.

The more genes are found that influence intelligence the greater will be the desire of future parents to use reproductive technologies to make little Jill and Johnnie smarter. Reports like this one indicate that we are coming up on a mad scramble to use offspring genetic engineering technologies. Us older people will be dumb compared to the average child born 50 years from now. If you are smart then are you prepared to find yourself in the left hand side of the intelligence distribution? Or do you plan to use cybernetic implants to keep up with the younger generations?

These researchers compared the volumes of a large number of areas of the brain between twins while also testing them for intelligence. They found genetic influences on the brain density of many areas of the brain as well as genetic influences on intelligence.

Although genetic effects on morphology of specific gray matter areas in the brain have been studied, the heritability of focal white matter was unknown until recently. Similarly, it was unresolved whether there is a common genetic origin of focal gray matter and white matter structures with intelligence. In our study involving 54 monozygotic and 58 dizygotic twin pairs and their 34 singleton siblings, verbal, and performal intelligence were found to share a common genetic origin with an anatomical neural network involving the frontal, occipital, and parahippocampal gray matter and connecting white matter of the superior occipitofrontal fascicle, and the corpus callosum [Hulshoff Pol et al., 2006]. For the genetic analyses, structural equation modeling and voxel-based morphometry were used. To explore the common genetic origin of focal gray matter and white matter areas with intelligence, cross-trait/cross-twin correlations were obtained in which the focal gray matter and white matter densities of each twin are correlated with the psychometric intelligence quotient of his/her cotwin.

The results of this study indicate that genes significantly influence white matter density of the superior occipitofrontal fascicle, corpus callosum, optic radiation, and corticospinal tract, as well as gray matter density of the medial frontal, superior frontal, superior temporal, occipital, postcentral, posterior cingulate, and parahippocampal cortices. Moreover, the results show that intelligence shares a common genetic origin with superior occipitofrontal, callosal, and left optical radiation white matter and frontal, occipital, and parahippocampal gray matter (phenotypic correlations up to 0.35).

These researchers aren't doing DNA sequencing because DNA sequencing still costs too much. But with costs of DNA sequencing and DNA testing rapidly falling brain researchers are going to be able to do massive genetic comparisons in 5 to 10 years that will give them a large enough quantity of genetic information to be able to run down and identify the genetic variations that cause differences in brain density, brain volume, and intelligence. Brain scans on much larger sets of twins combined with full genetic sequencing on those same twins will answer many of the questions we have about genetics and intelligence.

By Randall Parker    2007 October 16 05:35 PM   Entry Permalink | Comments (4)
2007 June 19 Tuesday
Brain Has 2 Decision Making Networks?

Ever feel like you are at 2 minds about something?

June 19, 2007 -- A probe of the upper echelons of the human brain's chain-of-command has found strong evidence that there are not one but two complementary commanders in charge of the brain, according to neuroscientists at Washington University School of Medicine in St. Louis.

It's as if Captains James T. Kirk and Jean-Luc Picard were both on the bridge and in command of the same starship Enterprise.

In reality, these two captains are networks of brain regions that do not consult each other but still work toward a common purpose — control of voluntary, goal-oriented behavior. This includes a vast range of activities from reading a word to searching for a star to singing a song, but likely does not include involuntary behaviors such as control of the pulse rate or digestion.

Brain scans show two separate networks of nodes making decisions.

Using an analytic technique originally developed by Raichle's group, scientists employed resting state functional connectivity MRI to identify pairs of brain regions where blood oxygen levels rose and fell roughly in synch with each other, implying the regions likely work together. They graphed the results, representing each brain region with a shape. They drew a line between paired brain regions if their blood oxygenation patterns correlated tightly enough. "You might expect that everything is connected to everything, and you would get sort of a big mess and not much information," Dosenbach says. "But that's not at all what we found. Even at low levels of correlation, there were two sides to these graphs. Brain regions on either side had multiple connections to other regions on their side, but they never connected to regions on the opposite side."

The two networks seem to have different purposes. The frontoparietal network sounds like it is more reactive.

Having established that two control networks existed, researchers turned back to their functional brain scans for insight into the networks' roles. One network, dubbed the cinguloopercular network, was linked to a "sustain" signal.

"When you start doing a task, this signal turns on," Petersen explains. "It stays constant while you're doing the task, and then when you're done it turns off."

In contrast, the frontoparietal network was consistently active at the start of mental tasks and during the correction of errors.

The balance between the two networks could vary from individual to individual. For example, some people might be better at maintaining a constant activity and others might be better at reacting to events.

By Randall Parker    2007 June 19 10:58 PM   Entry Permalink | Comments (4)
2006 April 27 Thursday
Gene Variation Influences Human Intelligence

Genetic variations associated with different risks of schizophrenia also influence intelligence levels among healthy volunteers.

GLEN OAKS, NY -- Psychiatric researchers at The Zucker Hillside Hospital campus of The Feinstein Institute for Medical Research have uncovered evidence of a gene that appears to influence intelligence. Working in conjunction with researchers at Harvard Partners Center for Genetics and Genomics in Boston, the Zucker Hillside team examined the genetic blueprints of individuals with schizophrenia, a neuropsychiatric disorder characterized by cognitive impairment, and compared them with healthy volunteers. They discovered that the dysbindin-1 gene (DTNBP1), which they previously demonstrated to be associated with schizophrenia, may also be linked to general cognitive ability. The study is published in the May 15 print issue of Human Molecular Genetics, available online today, April 27.

"A robust body of evidence suggests that cognitive abilities, particularly intelligence, are significantly influenced by genetic factors. Existing data already suggests that dysbindin may influence cognition," said Katherine Burdick, PhD, the study's primary author. "We looked at several DNA sequence variations within the dysbindin gene and found one of them to be significantly associated with lower general cognitive ability in carriers of the risk variant compared with non-carriers in two independent groups."

The study involved 213 unrelated Caucasian patients with schizophrenia or schizoaffective disorder and 126 unrelated healthy Caucasian volunteers. The researchers measured cognitive performance in all subjects. They then analyzed participants' DNA samples. The researchers specifically examined six DNA sequence variations, also known as single nucleotide polymorphisms (SNPs), in the dysbindin gene and found that one specific pattern of SNPs, known as a haplotype, was associated with general cognitive ability: Cognition was significantly impaired in carriers of the risk variant in both the schizophrenia group and the healthy volunteers as compared with the non-carriers.

"While our data suggests the dysbindin gene influences variation in human cognitive ability and intelligence, it only explained a small proportion of it -- about 3 percent. This supports a model involving multiple genetic and environmental influences on intelligence," said Anil Malhotra, MD, principal investigator of the study.

As DNA sequencing costs fall and larger amounts of genetic sequence differences are collected in humans many more genetic variations that influence intelligence and other cognitive characteristics will be found. The rate at which such genetic variations are identified will go up by orders of magnitude in the next 10 years.

By Randall Parker    2006 April 27 10:47 PM   Entry Permalink | Comments (4)
2005 December 25 Sunday
Intelligence Correlates With Brain Size

These results are consistent with lots of other studies which found a positive correlation between brain size and intelligence. Bigger is better.

Brain size matters for intellectual ability and bigger is better, McMaster University researchers have found.

The study, led by neuroscientist Sandra Witelson, a professor in the Michael G. DeGroote School of Medicine, and published in the December issue of the journal Brain, has provided some of the clearest evidence on the underlying basis of differences in intelligence.

The study involved testing of intelligence in 100 neurologically normal, terminally ill volunteers, who agreed that their brains be measured after death.

It found bigger is better, but there are differences between women and men.

In women, verbal intelligence was clearly correlated with brain size, accounting for 36 percent of the verbal IQ score. In men, this was true for right-handers only, indicating that brain asymmetry is a factor in men.

Spatial intelligence was also correlated with brain size in women, but less strongly. In men, spatial ability was not related to overall brain size. These results suggest that women may use verbal strategies in spatial thinking, but that in men, verbal and spatial thinking are more distinct.

How hard is it to measure gray versus white matter volumes in dead brains? My guess from other reading is that spatial reasoning abilities will vary more as a function of gray matter volume and perhaps more for gray matter in some areas of the brain than other areas.

It may be that the size or structure of the localized brain regions which underlie spatial skills in men is related to spatial intelligence, as was shown in previous research in Witelson's lab on the brain of Albert Einstein.

In a further sex difference, brain size decreased with age in men over the age span of 25 to 80 years, but age hardly affected brain size in women. It is not known what protective factors, which could be genetic, hormonal or environmental, operate in women.

It remains to be determined what the contribution of nature and nurture are to this cerebral size relationship with intelligence, Witelson said. She added that the results point to the need for responsibility in considering the likely future use of magnetic imaging (or MRIs) of brain structure as a measure of ability in student and workforce settings.

"We're going to need to be careful if, in the future, we use MRI brain scans as a measure of ability in any selection process," she said.

That brain size should correlate with intelligence strikes me as unsurprising on a number of grounds. The brain burns a disproportionate amount of fuel for its size. The brain is expensive for the body. Why should it be bigger unless being bigger provides some Darwinian fitness benefit? For larger brains to offer no benefit the people with smaller brains would need to have mutations that allow them to process just as much information but in a smaller space. But then why wouldn't such mutations sweep through a population?

I'm expecting we'll see the development of far more accurate ways to measure intelligence using MRI and other physical measures.

By Randall Parker    2005 December 25 10:41 PM   Entry Permalink | Comments (5)
2005 April 24 Sunday
Work Distractions Lower Effective IQ

Getting interrupted a lot by email and other messages has the equivalent effect on work efficiency of a 10 point IQ drop.

- One in five will break off from a business or social engagement to respond to a message.

- Nine out of 10 people thought colleagues who answered messages during face-to-face meetings were rude, while three out of 10 believed it was not only acceptable, but a sign of diligence and efficiency.

Note that if 9 out of 10 thinks it is rude to answer messages but 3 out of 10 think it is acceptable then doesn't that suggest that at least 2 out of ten think answering email messages while in meetings is both rude and acceptable? Hmmm....

Better to be stoned than to lose sleep or be interrupted?

- In 80 clinical trials, Dr. Glenn Wilson, a psychiatrist at King's College London University, monitored the IQ of workers throughout the day. He found the IQ of those who tried to juggle messages and work fell by 10 points -- the equivalent to missing a whole night's sleep and more than double the 4-point fall seen after smoking marijuana.

"This is a very real and widespread phenomenon," Wilson said. "We have found that this obsession with looking at messages, if unchecked, will damage a worker's performance by reducing their mental sharpness.

How real is this phenomenon? In my first real job I was placed in a small office next to the company's machine shop. While I tried to debug the software and hardware for a scientific instrument next door I heard drilling and hammering. I went to a gunshop and bought one of those headsets that target practice gunners use to protect their ears. It helped some.

"Companies should encourage a more balanced and appropriate way of working."

But many managers want their workers to promptly answer messages, promptly answer the phone, and come out to meetings and other distractions from getting work done.

Wilson said the IQ drop was even more significant in the men who took part in the tests.

"This is very, very real; but it is not a new phenomenon." Adam Boettiger, an author, publisher and professional coach to executives on time management and managing email overload says. "I've suspected the connection and witnessed it first-hand for years. Why this is a significant find is because (to my knowledge) it is the first clinical study that makes the connection."

Adam Boettiger is right. This is so not new.

The study was done using consistent types of problem solving tasks to measure differences of productivity under different conditions.

Eighty volunteers were asked to carry out problem solving tasks, firstly in a quiet environment and then while being bombarded with new emails and phone calls. Although they were told not to respond to any messages, researchers found that their attention was significantly disturbed.

Alarmingly, the average IQ was reduced by 10 points - double the amount seen in studies involving cannabis users. But not everyone was affected by to the same extent - men were twice as distracted as women.

Some things seem destined for repeat discovery until the results are finally taken seriously. Tom DeMarco and Timothy Lister reported years ago in their book Peopleware that computer programmers who get interrupted often enough by phone calls, intercom announcements, and other sources of interruption get literally nothing done. While the book is a vague memory for me at this point I recall that as part of their consulting work they did studies in companies where they measured the ability of staffs to complete some standard programming assignments and had the staffs keep records of their interruptions. Interrupt rates accounted for a large portion of differences in programmer productivity between companies. Some companies seem intent on treating their programmers and other knowledge workers as highly interruptible and distractable. Go figure.

The extent to which distractions decrease productivity depends on the type of mental work being performed. Some people work on much larger mental tasks, Therefore interrupts cause them to lose a lot of context from working memory. A person who is trying to picture and move around between many parts of a large computer program or a silicon chip design suffers a greater loss in productivty from being interrupted than, for example, a person who handles 5 minute service calls where the answers are pretty rote. Someone who writes complex technical manuals or who tries to find connections between many parts of a complex body of law similarly may hold a lot of mental state and the cost of interruption of such a person is much higher than, say, a person who is simply proofreading a legal document for obvious syntax and grammar errors.

Methods of batchng up interrupts would allow workers to have longer stretches of mental time during which to concentrate on handling large interacting sets of rules and relationships. For example, rather than having all email arrive immediately an email program could be set to check email only at many hour intervals. Perhaps email inboxes should be updated at lunch time so that a person could come back from lunch and process all new morning email at once. Also, imagine phone extensions where the message at the extension reports up "Bob will not be accepting calls for the next 93 minutes. Please call back at 3:30 PM to reach Bob".

Loud intercom announcements are evil, mmmkay? (and before anyone corrects my spelling you should hear that in the voice of Mr. Mackey of South Park) Then we come to cubicle land conditions where every office conversation carries over 5 foot high walls to interrupt the concentration of minds in at least a half dozen other cubicles. What to say about this madness? Words fail me. Working at home is much more productive.

Update: Note the larger effective IQ drop in men than in women. This is consistent observations I've read elsewhere: Women are less irritated by interruptions and can function better through interruptions. Is this a female adaptation for child raising? Young children are like distraction machines. A mother can't get too wrapped up in some work or else her toddlers might wander off into danger. Even if they are nearby they make noises or do other things that demand attention. Are female minds better adapted to dealing with these interrupts?

Men spend less time raising children even after decades of feminist demands for change. Our male ancestors were hunting while the women were gathering. Maybe male pursuits historically had less distractions and required focused concentration that was easier to achieve.

Another point here: Modern technology automates the production of distractions. Will the problem get worse? Think about futuristic movies that show signs reading the identity of passersby and generating voices that speak to each passing person by their real name. Think about advertisements geared ever more precisely to the interests of each customer. Sounds like a recipe for increasing distaction, lower productivity, and unhappier lives.

The technologies which produce distractions appear to be mining fertile ground. Human minds seem drawn to many kinds of distractions. Are we stimulus junkies? Or are our minds wired up to evaluate distractions as potential attacks from predators? Did selective pressure on our neolithic ancestors make our minds geared up to constantly evaluate messages from humans in order to check for potential threats?

But technology also provides means to filter out distractions. Don't want to look through bills every month? Set up auto-pay from your checking account to various utilities and credit cards. Also, tune in to satellite radio stations that have no commercials. Or listen to prerecorded music from your own music database rather than listen to a radio station. Lower tech methods to reduce distractions include soundproofing and closing the blinds. I personally like to work in low lighting conditions so that the clutter around me won't distract my mind from the computer screens in front of me.

Once business executives finally understand that they are providing productivity-robbing work environments to their employees (and business managers appear to be slow learners on this score) we can expect to see lower distraction workplaces become all the rage. Some of the distraction lowering technologies developed for workplaces will find their way into homes as well.

Some day in the future cars will drive themselves for much of commuter trips down electronically instrumented highways. Before then more people will work from home and at least for some home workers the distractions of driving will be eliminated altogether. But we need to find more lower and higher tech ways to reduce the distractions that lower our productivity and reduce our ability to enjoy leisure activities.

By Randall Parker    2005 April 24 02:50 PM   Entry Permalink | Comments (9)
2004 July 19 Monday
Brain Gray Matter Size Correlated To Intelligence

Size of grey matter areas of the brain more strongly correlate to IQ than does the overall size of the brain.

General human intelligence appears to be based on the volume of gray matter tissue in certain regions of the brain, UC Irvine College of Medicine researchers have found in the most comprehensive structural brain-scan study of intelligence to date.

The study also discovered that because these regions related to intelligence are located throughout the brain, a single “intelligence center,” such as the frontal lobe, is unlikely.

Dr. Richard Haier, professor of psychology in the Department of Pediatrics and long-time human intelligence researcher, and colleagues at UCI and the University of New Mexico used MRI to obtain structural images of the brain in 47 normal adults who also took standard intelligence quotient tests. The researchers used a technique called voxel-based morphometry to determine gray matter volume throughout the brain which they correlated to IQ scores. Study results appear on the online version of NeuroImage.

Previous research had shown that larger brains are weakly related to higher IQ, but this study is the first to demonstrate that gray matter in specific regions in the brain is more related to IQ than is overall size. Multiple brain areas are related to IQ, the UCI and UNM researchers have found, and various combinations of these areas can similarly account for IQ scores. Therefore, it is likely that a person’s mental strengths and weaknesses depend in large part on the individual pattern of gray matter across his or her brain.

“This may be why one person is quite good at mathematics and not so good at spelling, and another person, with the same IQ, has the opposite pattern of abilities,” Haier said.

While gray matter amounts are vital to intelligence levels, the researchers were surprised to find that only about 6 percent of all the gray matter in the brain appears related to IQ.

Attempts to deny the significance of IQ tests are being undermined by the results of physical measures of the brain using brain scanning technologies. The fact that IQ test correlates with the size of a particular type of brain tissue is a very strong indicator that IQ tests are measuring real physical differences in brain abilities.

The researchers found a curious result with the size of brain gray matter areas, age, and IQ correlation.

The findings also suggest that the brain areas where gray matter is related to IQ show some differences between young-adult and middle-aged subjects. In middle age, more of the frontal and parietal lobes are related to IQ; less frontal and more temporal areas are related to IQ in the younger adults.

The research does not address why some people have more gray matter in some brain areas than other people, although previous research has shown the regional distribution of gray matter in humans is highly heritable. Haier and his colleagues are currently evaluating the MRI data to see if there are gender differences in IQ patterns.

My guess is that the frontal areas are still developing in young adults and so are not capable of fully contributing to measured IQ until later in life. Though this article is too vague to tell what they mean by "young-adult".

Update: A January 2005 update on Haier's work shows that male and female brains differ greatly in their organization.

The study shows women having more white matter and men more gray matter related to intellectual skill, revealing that no single neuroanatomical structure determines general intelligence and that different types of brain designs are capable of producing equivalent intellectual performance.

“These findings suggest that human evolution has created two different types of brains designed for equally intelligent behavior,” said Richard Haier, professor of psychology in the Department of Pediatrics and longtime human intelligence researcher, who led the study with colleagues at UCI and the University of New Mexico. “In addition, by pinpointing these gender-based intelligence areas, the study has the potential to aid research on dementia and other cognitive-impairment diseases in the brain.”

Study results appear on the online version of NeuroImage.

In general, men have approximately 6.5 times the amount of gray matter related to general intelligence than women, and women have nearly 10 times the amount of white matter related to intelligence than men. Gray matter represents information processing centers in the brain, and white matter represents the networking of – or connections between – these processing centers.

This, according to Rex Jung, a UNM neuropsychologist and co-author of the study, may help to explain why men tend to excel in tasks requiring more local processing (like mathematics), while women tend to excel at integrating and assimilating information from distributed gray-matter regions in the brain, such as required for language facility.

The environmentalist Blank Slate view of the mind is becoming ever harder to defend.

By Randall Parker    2004 July 19 12:23 PM   Entry Permalink | Comments (12)
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