In the study, a joint effort of psychologists at the U.S. Army Research Institute for the Behavioral and Social Sciences at Fort Benning, Ga. and the University of Melbourne, Australia, researchers studied 60 right-handed males: 18 mathematically gifted (averaging nearly 14 years in age), 18 of average math ability (averaging just over 13), and 24 college students (averaging about 20). Math giftedness seems to favor boys over girls, appearing an estimated six to 13 times more often. It's not known why but prenatal exposure to testosterone is suspected to be one influence due to its selective benefit to the right half of the brain.
The gifted boys were recruited from a Challenges for Youth-Talented program at Iowa State University. Whereas the average Scholastic Aptitude Test (SAT) math score for college-bound high-school seniors is 500 (out of 800), the mathematically gifted boys' average SAT math score in middle school was 620.
The boys viewed letter patterns flashed on the left or right sides of a computer screen, and had to indicate whether two patterns matched or not – a simple way of learning how the brain responds to data put before either the left or right visual field, corresponding to processing in the right or left brain because the input generally crosses over to the other side.
The letter patterns were presented in three conditions – one-sided, to the right hemisphere (left eye); one-sided, to the left hemisphere (right eye); or bilaterally (both eyes). There were two types of tasks -- "local," saying two letters matched or mismatched on the small letters that went into making big letters (for example, a big T whose two strokes were made of smaller T's), and "global," saying two big letters matched or mismatched.
For the average teens and college students, the left brain hemisphere was faster for local matches and the right brain hemisphere was faster for global matches. This fit prior research, which has indicated that the left hemisphere is adept at processing visual "parts," in this case the letter details, while the right hemisphere is more adept at analyzing visual "wholes," in this case the global shapes of the big letters.
However, the mathematically gifted boys showed no such hemispheric differences. Those who were precocious in math were equally good at processing global and local elements with either hemisphere, suggesting more interactive, cooperative left and right brains.
In addition, whereas average-ability boys and college students were slower on cooperative trials, which presented letter patterns on both sides of the screen, the math-gifted showed the opposite pattern. They were slower on one-sided trials, but when a task "asked" both sides of the brain to work together, they were considerably faster than the other boys.
The study supports the growing notion that the mathematically gifted are better at relaying and integrating information between the cerebral hemispheres. Says co-author Michael O'Boyle, PhD, "It's not that you have a special math module somewhere in your brain, but rather that the brain's particular functional organization – which allows right-hemisphere contributions to be better integrated into the overall cognitive/behavioral equation -- predisposes it towards the use of high-level imagery and spatial skills, which in turn just happen to be very useful when it comes to doing math reasoning."
The research supports the broader notion that "the functional (though not necessarily structural) organization of the brain may be an important contributor to individual differences in cognitive abilities, talents and, at the very least, information-processing styles," says O'Boyle.
He adds, "Various expressions of exceptionality, such as giftedness in math, music or art, may be the by-product of a brain that has functionally organized itself in a qualitatively different way than the usual left/right hemispheric asymmetry."
At the same time, O'Boyle is not sure whether the findings could apply to math education in general. "Our work may perhaps have something to say about the optimal timing of when a particular brain is most 'ready to learn' or acquire a given skill, but I don't think we can 'create' a math genius without the innate talent already there," he says.
Finally, given the rising use of testosterone by adult men, O'Boyle cautions that, "Testosterone taken later in life will not help your math, as the window of influence on brain development is pretty much prenatal. It may enhance muscle mass, but it is unlikely to help you solve calculus problems."
Article: "Interhemispheric interaction during global-local processing in mathematically gifted adolescents, average-ability youth, and college students," Harnam Singh, Ph.D., U.S. Army Research Institute for the Behavioral and Social Sciences, and Michael W. O'Boyle, PhD, University of Melbourne, Australia; Neuropsychology, Vol. 18, No. 2.
(Full text of the article is available from the APA Public Affairs Office and at http://www.apa.org/releases/interhemispheric_article.pdf )
Michael O'Boyle can be reached at m.oboyle@ psych.unimelb.edu.au or by phone at 61-3-8344-4013.
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