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Nature vs. nurture divides academia

Some see merit in saying biology may have role in gender inequities

NEW YORK -- Harvard University president Lawrence Summers has been harshly criticized for suggesting that the underrepresentation of women in engineering and some scientific fields may be due in part to inherent differences in intellectual abilities.

But some psychologists and neuroscientists who know about the differences between men's and women's brains believe his remarks have merit and support more research on the subject.

''Among people who do the research, it's not so controversial. There are lots and lots of studies that show that men's and women's brains are different," says Richard J. Haier, a professor of psychology in the pediatrics department of the University of California, Los Angeles medical school.

Academia has been bitterly divided by the nature vs. nurture debate, and the Harvard president's comments last month at a National Bureau of Economic Research symposium touched on aspects that are so controversial that the opposing sides almost never discuss them.

On one side are those who believe the sexes are equal enough in their intellectual abilities that any biological difference is vastly outweighed by social pressures and discrimination that discourage girls and women from pursuing science and engineering.

''When people hear 'biology,' they think there's nothing you can do about it," said Joshua Aronson, a professor of applied psychology at New York University. ''It's in that context that Summers' remarks are not helpful."

But there are those who believe that biological differences between men and women really can account for at least some of the underrepresentation of women in engineering and some fields of science. They say more research could shed light on how individuals overcome differences to accomplish what they do.

''I think it's an outrage that certain questions -- that real, important questions -- can't be raised in an academic atmosphere, that research that's well-known can't be presented without some sort of hysterical response," said Linda S. Gottfredson, a psychologist at the University of Delaware.

In recent years, neuroscientists have found that male and female brains are wired differently because of the role of testosterone and other male hormones during gestation. Brains growing under the influence of male hormones are slightly larger and have denser concentrations of neurons in some regions.

Male brains also contain a greater proportion of gray matter, the part of the brain responsible for computation, while women have relatively more white matter, which specializes in making connections between brain cells.

Brain-imaging studies suggest that both sexes can exploit the differences to their benefit. UCLA researchers have done brain scans of men and women who scored in the top 1 percent on the math section of the SAT. As they worked on math problems, the men relied heavily on the gray matter in the brain's parietal and cerebral cortices. Women showed greater activity in areas dominated by the well-connected white matter.

Average IQ is the same among men and women.

Intelligence tests have found that men, on average, perform better on spatial tasks that require mentally manipulating objects. Men also do better on tests of mathematical reasoning. Women tend to do better on tasks requiring verbal memory and distinguishing whether objects are similar. The relative strengths tend to even out, studies indicate.

If men do have a slight advantage in math ability, is the difference really biological, or are exceptional girls and women intimidated by cultural stereotypes and discouraged from cultivating their talents from an early age?

''If I had to guess, the real reason for the lack of women in the upper strata is that there's a comfort zone when you walk into a classroom and see a certain number of people like you," said Aronson, the New York University professor.

Female physicists and engineers almost always live their entire professional lives outside that comfort zone. Aronson and his colleagues have shown that many of the performance differences between men and women, and among races, can be erased with minor adjustments that influence test-takers' confidence.

''This suggests there's something about the testing situation itself," Aronson said. ''If there is a biological difference, then it's one that's awfully easy to overcome."

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