Sex differences in fluid intelligence among high school graduates

There is contradictory empirical evidence concerning the problem of whether there is a sex difference in general intelligence. Some researchers claim that there is a sex difference, relying on the summation of the standardized sex differences in cognitive tests measuring verbal, spatial, and reasoning abilities. Other researchers state that there is not a sex difference in general intelligence; they propose that general intelligence should be conceptualized as g. g is not the result of the simple summation of tests scores, but a source of variance evidenced by the correlation among several diverse tests. We think it is possible to resolve this conflict. Fluid intelligence (Gf) is usually conceived as the core of intelligent behavior [Carroll, J. B. (1993). Human cognitive abilities. Cambridge: Cambridge University Press]. Therefore, if there is a sex difference in general intelligence, it could be systematically detected in measures of Gf. Three measures of Gf were used in the present study: the PMA Inductive Reasoning Test, the Advanced Progressive Matrices (APM), and the Culture-Fair Intelligence Test (Scale 3). A total of 4072 high school graduates was tested (1772 females and 2300 males). The results reveal that females outperform males in the PMA Reasoning test, that males outperform females in the Raven, and that there is no sex difference in the Culture-Fair Test. Therefore, given that there is no systematic difference favoring any sex in the measures of Gf, and that there is no sex difference in the best available measure of Gf (the Culture-Fair Test), it is concluded that the sex difference in fluid intelligence is non-existent.