The sex difference on one test of spatial visualization: a nontrivial difference.

Plomin and Foch's conclusion that sex differences in cognition account for very little of the total variability is challenged by demonstrating that, on a complex test of spatial visualization, the difference between males and females accounts for a quite substantial portion of the variability of the test scores. 2 measures of spatial visualization--the ETS Card Rotations test and the Shepard/Metzler Mental Rotations test--were administered to a large sample of college students. The Card Rotations test requires identification of fairly simple abstract forms after rotation within the plane; the Mental Rotations test requires identification of representations of more complex 3-dimensional figures after rotation in 3-dimensional space. Males scored significantly higher than females on both tests. Sex accounted for only 2% of the variance on the Card Rotations test but for 16% of the variance on the Mental Rotations test. Comparable sex differences on the Shepard/Metzler Mental Rotations test have also been found by other investigators.