Developments in Brief : Biological Factors May Tell the Boys From the Girls in Mathematics Tests

Biological factors may be more important than environmental factors in explaining why boys tend to outscore girls on mathematics tests, even though their verbal skills are statistically identical, reports Iowa State University psychologist Camilla P. Benbow.

She said studies in recent years simply have not found conclusive links between how girls are reared and their math skills, while biological research has shown that the male hormone testosterone may enhance development of the part of the brain responsible for reasoning needed in math.

When the discrepancy was first publicized in 1971, many theorized that girls are not as adept at math because of the way they are reared, the way they are treated in classrooms and even the toys with which they are taught to play. But subsequent studies, involving hundreds of girls, do not bear out the theory.

“They lend credence to the viewpoint that these sex differences may have a biological component,” Benbow said last week at the annual meeting of the American Assn. for the Advancement of Science. She said related studies have shown that math skills of girls can improve with encouragement and special teaching techniques.

At the same time, biological studies have shown that fetuses exposed to high levels of testosterone often favor their left hands and develop immune disorders such as allergies. Both of these traits are twice as common in mathematically gifted children than in other children. These studies suggest that testosterone slows the development of the brain’s left hemisphere, thus enhancing the development of the right, which is associated with many of the reasoning skills needed to solve mathematical problems, Benbow said.