Now a team of psychologists at Duke University has looked at the results of tests with more headroom. In an article in a forthcoming issue of the journal Intelligence, they analyze the test scores of students in the United States who took college admissions tests while they were still in the seventh grade. As part of an annual talent search since 1981, the SAT and ACT tests have been given to more than 1.6 million gifted seventh graders, with roughly equal numbers of boys and girls participating.

The Duke researchers — Jonathan Wai, Megan Cacchio, Martha Putallaz and Matthew C. Makel — focused on the extreme right tail of the distribution curve: people ranking in the top 0.01 percent of the general population, which for a seventh grader means scoring above 700 on the SAT math test. In the early 1980s, there were 13 boys for every girl in that group, but by 1991 the gender gap had narrowed to four to one, presumably because of sociocultural factors like encouragement and instruction in math offered to girls.

Since then, however, the math gender gap hasn’t narrowed, despite the continuing programs to encourage girls. The Duke researchers report that there are still four boys for every girl at the extreme right tail of the scores for the SAT math test. The boy-girl ratio has also remained fairly constant, at about three to one, at the right tail of the ACT tests of both math and science reasoning. Among the 19 students who got a perfect score on the ACT science test in the past two decades, 18 were boys.

Meanwhile, the seventh-grade girls outnumbered the boys at the right tail of tests measuring verbal reasoning and writing ability. The Duke researchers report in Intelligence, “Our data clearly show that there are sex differences in cognitive abilities in the extreme right tail, with some favoring males and some favoring females.”