X-linkage of spatial ability: a critical review.

The hypothesis that a major X-linked gene determines spatial ability in man has been cited as an explanation for the adult sex difference in spatial ability. Here the relevant literature is critically reviewed. Early studies often used multiple comparisons, yet repeatedly failed to find significant differences. In some cases the results flatly contradicted the hypothesis, and those results that were consistent with it can be accounted for by chance expectancies. Recent evidence comes from studies that are methodologically superior to the early work; yet these studies provide no support for the X-linkage of spatial ability. It is concluded that belief in the validity of the hypothesis is unfounded.