http://online.wsj.com/article/SB10001424052970203752604576641133332697322.htmlAs Brain Changes, So Can IQ
Study Finds Teens' Intellects May Be More Malleable Than Previously Thought
By ROBERT LEE HOTZ
Wall Street Journal
OCTOBER 20, 2011
A teenager's IQ can rise or fall as many as 20 points in just a few years, a brain-scanning team found in a study published Wednesday that suggests a young person's intelligence measure isn't as fixed as once thought.
The researchers also found that shifts in IQ scores corresponded to small physical changes in brain areas related to intellectual skills, though they weren't able to show a clear cause and effect.
"If the finding is true, it could signal environmental factors that are changing the brain and intelligence over a relatively short period," said psychologist Robert Plomin at Kings College in London, who studies the genetics of intelligence and wasn't involved in the research. "That is quite astounding."
Long at the center of debates over how intelligence can be measured, an IQ score�the initials stand for "intelligence quotient"�typically gauges mental capacity through a battery of standardized tests of language skill, spatial ability, arithmetic, memory and reasoning. A score of 100 is considered average. Barring injury, that intellectual capacity remains constant throughout life, most experts believe.
But the new findings by researchers at University College London, reported online in Nature, suggest that IQ, often used to predict school performance and job prospects, may be more malleable than previously believed�and more susceptible to outside influences, such as tutoring or neglect.
"A change in 20 points is a huge difference," said the team's senior researcher, Cathy Price, at the university's Wellcome Trust Centre for Neuroimaging. Indeed, it can mean the difference between being rated average and being labeled gifted�or, conversely, being categorized as substandard.
Researchers found that dramatic changes in verbal IQ corresponded to changes in an area of the brain associated with speech, whereas nonverbal IQ changes were related to an area involved in hand movements.
To better understand intelligence, Dr. Price and her colleagues studied 33 healthy British teenagers whose IQ scores initially ranged from 80 to 140. They tested the volunteers on standardized intelligence exams in 2004 and again in 2008, to encompass the peak years of their adolescence, while monitoring subtle changes in brain structure using functional magnetic resonance imaging.
By analyzing verbal and nonverbal IQ performance separately, the researchers discovered that these fundamental facets of intelligence could change markedly, even in cases when an overall composite IQ score remained relatively constant.
"One fifth of them jumped one way or the other," Dr. Price said. One teenager's verbal IQ score rose to 138 at age 17 from 120 at age 13, while her nonverbal IQ dropped to a below-average score of85 from 103. Another's verbal IQ soared to 127 from 104 in four years, while his nonverbal performance stayed the same.
A teenager's IQ can rise or fall up to 20 points in just a few years, in a finding that pinpoints unexpected variations in a measure of intelligence often used to predict school performance and job prospects. Robert Lee Hotz explains on The News Hub.
The rise or fall in verbal IQ scores appeared to be connected to changes in an area of the brain associated with speech, whereas shifts in nonverbal IQ related to an area involved in motor control and hand movements.
In recent years, scientists have determined that experience can readily alter the brain, as networks of neural synapses bloom in response to activity or wither with disuse. Expert musicians, circus jugglers and London cab drivers studying maps�even Colombian guerillas learning to read�have all shown brain changes linked to practice, several brain imaging studies have reported. But until now, researchers had considered general intelligence too basic to be affected by such relatively small neural adjustments. Dr. Price and her colleagues don't know what caused the changes in both the brain and the scores they documented, but speculated they could be a result of learning experiences.
Several brain specialists said the changes could just as plausibly reflect the pace of normal growth, and shifts in scores could be due to inconsistent test performance.
The varying IQ scores could also indicate the test itself is flawed. "It could be a real index of how intelligence varies or it could suggest our measures of intelligence are so variable," said neuroimaging pioneer B.J. Casey at Cornell University's Weill Medical College, who wasn't involved in the study.
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Here is the abstract, from
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10514.html :
Verbal and non-verbal intelligence changes in the teenage brain
Sue Ramsden, Fiona M. Richardson, Goulven Josse, Michael S. C. Thomas, Caroline Ellis, Clare Shakeshaft, Mohamed L. Seghier & Cathy J. Price
Nature (2011) doi:10.1038/nature10514
Received 17 May 2011 Accepted 26 August 2011 Published online 19 October 2011
ntelligence quotient (IQ) is a standardized measure of human intellectual capacity that takes into account a wide range of cognitive skills1. IQ is generally considered to be stable across the lifespan, with scores at one time point used to predict educational achievement and employment prospects in later years1. Neuroimaging allows us to test whether unexpected longitudinal fluctuations in measured IQ are related to brain development. Here we show that verbal and non-verbal IQ can rise or fall in the teenage years, with these changes in performance validated by their close correlation with changes in local brain structure. A combination of structural and functional imaging showed that verbal IQ changed with grey matter in a region that was activated by speech, whereas non-verbal IQ changed with grey matter in a region that was activated by finger movements. By using longitudinal assessments of the same individuals, we obviated the many sources of variation in brain structure that confound cross-sectional studies. This allowed us to dissociate neural markers for the two types of IQ and to show that general verbal and non-verbal abilities are closely linked to the sensorimotor skills involved in learning. More generally, our results emphasize the possibility that an individual�s intellectual capacity relative to their peers can decrease or increase in the teenage years. This would be encouraging to those whose intellectual potential may improve, and would be a warning that early achievers may not maintain their potential.
