Familial resemblance for the Identical Blocks Test of spatial ability: no evidence for X linkage.

The Identical Blocks Test of spatial ability was administered to subsamples of the two largest ethnic groups tested in the Hawaii Family Study of Cognition--Americans of European ancestry (171 families) and Americans of Japanese ancestry (98 families). Results of a hierarchical multiple regression analysis of family data and correlational analyses provided no evidence to support the hypothesis that spatial ability is influenced by a major, X-linked, recessive gene. Thus it appears that recent failures to replicate the sex-linkage pattern obtained by Stafford (1961) are not due to differences in the tests employed. We suggest that alternative explanations should be sought for the well-known sex difference in spatial ability.