NEWTON, Mass. - Boys score higher on math tests mostly because of better spatial skills, say researchers who found that girls' math anxiety doesn't figure nearly so much into the equation.
Girls might do better at both spatial skills and math by competing in sports, the study found.
"The take-home message is, `Wake up and think about spatial skills,"' said M. Beth Casey, a developmental psychology professor at Boston College and the report's lead author.
The study, published in the current issue of Developmental Psychology, was an examination of competing explanations for why boys consistently outscore girls on the math part of the Scholastic Assessment Test.
Researchers found that nearly two-thirds of the measurable differences in math scores - 64 percent - was attributable to boys' better spatial ability, and 36 percent to girls' lower self-confidence.
The 94 high school students in the study were tested as sophomores on spatial skills - the ability to mentally visualize and rotate 3-dimensional objects - and on their math self-confidence. Two years later, their SAT scores and math grades were compared.
The students were among the top one-third of college-bound students in suburban Melrose schools.
Girls' higher math anxiety did not affect their scores on the math SATs, the study found.
And since boys are encouraged at early ages to play with blocks and toys such as model airplanes, and later to participate in sports, girls would do well to get the same encouragement, Casey said.
"It's important to have girls develop spatial skills. We need to think about providing those kinds of experiences, starting at an early age," she said in today's editions of The Boston Globe.
The authors took "the most reasonable approach" in suggesting that a combination of heredity and environment is involved in math test score differences, said psychology professor Julian C. Stanley, director of the Study of Mathematically Precocious Youth at Johns Hopkins University.
But he said he has not seen proof that the difference can be eliminated by teaching girls better spatial skills or that such skills can be taught.