An analysis of 145 items found a male IQ advantage of 3.63 points.
It also found that the g factor—the general factor of mental ability underlay both the SAT Verbal (SAT-V) and the SAT Mathematics (SAT-M) scales with the congruence between these components greater than 0.90, and that it was the g factor that predicted student grades better than the traditionally used SAT-V and SAT-M scales.
The male and the female g factors were congruent in excess of .99, and they favored males to an equivalent of 3.63 IQ points.
The male-female differences were present at every socioeconomic level, and across several ethnic groups.
The average male advantage was found “throughout the entire distribution of scores, in every level of family income, for every level of fathers’ and of mothers’ education, and for each and every one of seven ethnic groups,” said J. Philippe Rushton, professor of psychology at the University of Western Ontario, one of the authors of the study.
The paper’s results dovetail with those from several other recently published studies showing that men—surprisingly—
As such, the findings overturn a 100 year consensus that men and women average the same in general mental ability.
Because girls mature faster than boys, the sex difference is masked during the school years. Since almost all the data showing an absence of sex differences were gathered on school children, this might explain why the sex difference was missed for so long.
For decades, however, psychologists have accepted that men and women differ in their test “profiles,”
The authors of the study, psychologists Douglas N. Jackson and J. Philippe Rushton at the University of Western Ontario, conducted the study because two recent sets of observations had raised anew the question of sex differences in general intelligence.
The first was that the general factor of mental ability—g—
More than any other factor, the test’s g loading best determines a test’s power to predict academic achievement, creativity, career potential, and job performance. Hence, the question of sex differences became formulated more precisely as: “Are there sex differences on the g factor?”
British psychologist Richard Lynn at the University of Ulster in Northern Ireland, and Paul Irwing at the University of Manchester found that adult men consistently average 4 to 5 IQ points higher than adult women in a series of recent large-scale studies using a number of intelligence tests in various countries. (Irwing & Lynn’s most recent paper appeared in Nature on July 6, 2006.)
Prof. Rushton agreed that “these are unpopular conclusions.”
Prof. Rushton accepted that sex differences in general mental ability could help explain the “glass ceiling” phenomenon. But he also noted the paradox that although men may have higher IQ scores, women do increasingly well in school exams.
