[tt] The Neurological Roots of Genius

[Hughes, James J.]

http://www.sciam.com/article.cfm?id=high-aptitude-minds

Scientific American Mind -  September 4, 2008

High-Aptitude Minds: The Neurological Roots of Genius

Researchers are finding clues to the basis of brilliance in the brain

By Christian Hoppe and Jelena Stojanovic

Within hours of his demise in 1955, Albert Einstein's brain was
salvaged, sliced into 240 pieces and stored in jars for safekeeping.
Since then, researchers have weighed, measured and otherwise inspected
these biological specimens of genius in hopes of uncovering clues to
Einstein's spectacular intellect.

Their cerebral explorations are part of a century-long effort to uncover
the neural basis of high intelligence or, in children, giftedness.
Traditionally, 2 to 5 percent of kids qualify as gifted, with the top 2
percent scoring above 130 on an intelligence quotient (IQ) test. (The
statistical average is 100. See the box on the opposite page.) A high IQ
increases the probability of success in various academic areas. Children
who are good at reading, writing or math also tend to be facile at the
other two areas and to grow into adults who are skilled at diverse
intellectual tasks [see "Solving the IQ Puzzle," by James R. Flynn;
Scientific American Mind, October/November 2007].

Most studies show that smarter brains are typically bigger-at least in
certain locations. Part of Einstein's parietal lobe (at the top of the
head, behind the ears) was 15 percent wider than the same region was in
35 men of normal cognitive ability, according to a 1999 study by
researchers at McMaster University in Ontario. This area is thought to
be critical for visual and mathematical thinking. It is also within the
constellation of brain regions fingered as important for superior
cognition. These neural territories include parts of the parietal and
frontal lobes as well as a structure called the anterior cingulate.

But the functional consequences of such enlargement are controversial.
In 1883 English anthropologist and polymath Sir Francis Galton dubbed
intelligence an inherited feature of an efficiently functioning central
nervous system. Since then, neuroscientists have garnered support for
this efficiency hypothesis using modern neuroimaging techniques. They
found that the brains of brighter people use less energy to solve
certain prob-lems than those of people with lower aptitudes do.

In other cases, scientists have observed higher neuronal power
consumption in individuals with superior mental capacities. Musical
prodigies may also sport an unusually energetic brain [see box on page
67]. That flurry of activity may occur when a task is unusually
challenging, some researchers speculate, whereas a gifted mind might be
more efficient only when it is pondering a relatively painless puzzle.

Despite the quest to unravel the roots of high IQ, researchers say that
people often overestimate the significance of intellectual ability [see
"Coaching the Gifted Child," by Christian Fischer]. Studies show that
practice and perseverance contribute more to accomplishment than being
smart does.

Size Matters

In humans, brain size correlates, albeit somewhat weakly, with
intelligence, at least when researchers control for a person's sex (male
brains are bigger) and age (older brains are smaller). Many modern
studies have linked a larger brain, as measured by magnetic resonance
imaging, to higher intellect, with total brain volume accounting for
about 16 percent of the variance in IQ. But, as Einstein's brain
illustrates, the size of some brain areas may matter for intelligence
much more than that of others does.

In 2004 psychologist Richard J. Haier of the University of California,
Irvine, and his colleagues reported evidence to support the notion that
discrete brain regions mediate scholarly aptitude. Studying the brains
of 47 adults, Haier's team found an association between the amount of
gray matter (tissue containing the cell bodies of neurons) and higher IQ
in 10 discrete regions, including three in the frontal lobe and two in
the parietal lobe just behind it. Other scientists have also seen more
white matter, which is made up of nerve axons (or fibers), in these same
regions among people with higher IQs. The results point to a widely
distributed-but discrete-neural basis of intelligence.

The neural hubs of general intelligence may change with age. Among the
younger adults in Haier's study-his subjects ranged in age from 18 to
84-IQ correlated with the size of brain regions near a central structure
called the cingulate, which participates in various cognitive and
emotional tasks. That result jibed with the findings, published a year
earlier, of pediatric neurologist Marko Wilke, then at Cincinnati
Children's Hospital Medical Center, and his colleagues. In its survey of
146 children ages five to 18 with a range of IQs, the Cincinnati group
discovered a strong connection between IQ and gray matter volume in the
cingulate but not in any other brain structure the researchers examined.

Scientists have identified other shifting neural patterns that could
signal high IQ. In a 2006 study child psychiatrist Philip Shaw of the
National Institute of Mental Health and his colleagues scanned the
brains of 307 children of varying intelligence multiple times to
determine the thickness of their cerebral cortex, the brain's exterior
part. They discovered that academic prodigies younger than eight had an
unusually thin cerebral cortex, which then thickened rapidly so that by
late childhood it was chunkier than that of less clever kids. Consistent
with other studies, that pattern was particularly pronounced in the
frontal brain regions that govern rational thought processes.

The brain structures responsible for high IQ may vary by sex as well as
by age. A recent study by Haier, for example, suggests that men and
women achieve similar results on IQ tests with the aid of different
brain regions. Thus, more than one type of brain architecture may
underlie high aptitude.

Low Effort Required

Meanwhile researchers are debating the functional consequences of these
structural findings. Over the years brain scientists have garnered
evidence supporting the idea that high intelligence stems from faster
information processing in the brain. Underlying such speed, some
psychologists argue, is unusually efficient neural circuitry in the
brains of gifted individuals.

Experimental psychologist Werner Krause, formerly at the University of
Jena in Germany, for example, has proposed that the highly gifted solve
puzzles more elegantly than other people do: they rapidly identify the
key information in them and the best way to solve them. Such people
thereby make optimal use of the brain's limited working memory, the
short-term buffer that holds items just long enough for the mind to
process them.

Starting in the late 1980s, Haier and his colleagues have gathered data
that buttress this so-called efficiency hypothesis. The researchers used
positron-emission tomography, which measures glucose metabolism of
cells, to scan the brains of eight young men while they performed a
nonverbal abstract reasoning task for half an hour. They found that the
better an individual's performance on the task, the lower the metabolic
rate in widespread areas of the brain, supporting the notion that
efficient neural processing may underlie brilliance. And in the 1990s
the same group observed the flip side of this phenomenon: higher glucose
metabolism in the brains of a small group of subjects who had
below-average IQs, suggesting that slower minds operate less
economically.

More recently, in 2004 psychologist Aljoscha Neubauer of the University
of Graz in Austria and his colleagues linked aptitude to diminished
cortical activity after learning. The researchers used
electroencephalography (EEG), a technique that detects electrical brain
activity at precise time points using an array of electrodes affixed to
the scalp, to monitor the brains of 27 individuals while they took two
reasoning tests, one of them given before test-related training and the
other after it. During the second test, frontal brain regions-many of
which are involved in higher--order cognitive skills-were less active in
the more intelligent individuals than in the less astute subjects. In
fact, the higher a subject's mental ability, the bigger the dip in
cortical activation between the pretraining and posttraining tests,
suggesting that the brains of brighter individuals streamline the
processing of new information faster than those of their less
intelligent counterparts do.

The cerebrums of smart kids may also be more efficient at rest,
according to a 2006 study by psychologist Joel Alexander of Western
Oregon University and his colleagues. Using EEG, Alexander's team found
that resting eight- to 12-hertz alpha brain waves were significantly
more powerful in 30 adolescents of average ability than they were in 30
gifted adolescents, whose alpha-wave signal resembled those of older,
college-age students. The results suggest that gifted kids' brains use
relatively little energy while idle and in this respect resemble more
developmentally advanced human brains.

Some researchers speculate that greater energy efficiency in the brains
of gifted individuals could arise from increased gray matter, which
might provide more resources for data processing, lessening the strain
on the brain. But others, such as economist Edward Miller, formerly of
the University of New Orleans, have proposed that the efficiency boost
could also result from thicker myelin, the substance that insulates
nerves and ensures rapid conduction of nerve signals. No one knows if
the brains of the quick-witted generally contain more myelin, although
Einstein's might have. Scientists probing Einstein's brain in the 1980s
discovered an unusual number of glia, the cells that make up myelin,
relative to neurons in one area of his parietal cortex.

Hardworking Minds

And yet gifted brains are not always in a state of relative calm. In
some situations, they appear to be more energetic, not less, than those
of people of more ordinary intellect. What is more, the energy-gobbling
brain areas roughly correspond to those boasting more gray matter,
suggesting that the gifted may simply be endowed with more brainpower in
this intelligence network.

In a 2003 trial psychologist Jeremy Gray, then at Washington University
in St. Louis, and his colleagues scanned the brains of 48 individuals
using functional MRI, which detects neural activity by tracking the flow
of oxygenated blood in brain tissue, while the subjects completed hard
tasks that taxed working memory. The researchers saw higher levels of
activity in prefrontal and parietal brain regions in the participants
who had received high scores on an intelligence test, as compared with
low scorers.

In a 2005 study a team led by neuroscientist Michael O'Boyle of Texas
Tech University found a similar brain activity pattern in young male
math geniuses. The researchers used fMRI to map the brains of
mathematically gifted adolescents while they mentally rotated objects to
try to match them to a target item. Compared with adolescent boys of
average math ability, the brains of the mathematically talented boys
were more metabolically active-and that activity was concentrated in the
parietal lobes, the frontal cortex and the anterior cingulate.

A year later biologist Kun Ho Lee of Seoul National University in Korea
similarly linked elevated activity in a frontoparietal neural network to
superior intellect. Lee and his co-workers measured brain activity in 18
gifted adolescents and 18 less intelligent young people while they
performed difficult reasoning tasks. These tasks, once again, excited
activity in areas of the frontal and parietal lobes, including the
anterior cingulate, and this neural commotion was significantly more
intense in the gifted individuals' brains.

No one is sure why some experiments indicate that a bright brain is a
hardworking one, whereas others suggest it is one that can afford to
relax. Some, such as Haier-who has found higher brain metabolic rates in
more astute individuals in some of his studies but not in
others-speculate one reason could relate to the difficulty of the tasks.
When a problem is very complex, even a gifted person's brain has to work
to solve it. The brain's relatively high metabolic rate in this instance
might reflect greater engagement with the task. If that task was out of
reach for someone of average intellect, that person's brain might be
relatively inactive because of an inability to tackle the problem. And
yet a bright individual's brain might nonetheless solve a less difficult
problem efficiently and with little effort as compared with someone who
has a lower IQ.

Perfection from Practice

Whatever the neurological roots of genius, being brilliant only
increases the probability of success; it does not ensure accomplishment
in any endeavor. Even for academic achievement, IQ is not as important
as self-discipline and a willingness to work hard.

University of Pennsylvania psychologists Angela Duckworth and Martin
Seligman examined final grades of 164 eighth-grade students, along with
their admission to (or rejection from) a prestigious high school. By
such measures, the researchers determined that scholarly success was
more than twice as dependent on assessments of self-discipline as on IQ.
What is more, they reported in 2005, students with more
self-discipline-a willingness to sacrifice short-term pleasure for
long-term gain-were more likely than those lacking this skill to improve
their grades during the school year. A high IQ, on the other hand, did
not predict a climb in grades.

A 2007 study by Neubauer's team of 90 adult tournament chess players
similarly shows that practice and experience are more important to
expertise than general intelligence is, although the latter is related
to chess-playing ability. Even Einstein's spectacular success as a
mathematician and a physicist cannot be attributed to intellectual
prowess alone. His education, dedication to the problem of relativity,
willingness to take risks, and support from family and friends probably
helped to push him ahead of any contemporaries with comparable cognitive
gifts.