Spatial ability and throwing accuracy.

In an attempt to explain the superior spatial skill of males, several studies have investigated the hypothesis that spatial ability is enhanced by an Xlinked recessive gene. Some of the evidence based on intrafamilial correlations supports the X-linkage hypothesis of superior male spatial ability (Stafford, 1961 ; Hartlage, 1970; Bock and Kolakowski, 1973; Yen, 1975) while more recent work, including our own, does not (DeFries et al., 1976a, 1979; Bouchard and McGee, 1977; Loehlin et al., 1978; Park et al., 1978; Jardine and Martin, 1983). While the X-linkage hypothesis now seems unlikely, the evidence that experiential factors are critical in the development of spatial skills is not convincing. If sex differences in spatial skill reflect differential learning due to sex-typed activities, then appropriate training should result in improved performance. Brinkmann (1966), studying male and female high-school students, found after 3 weeks of instruction that the girls did not significantly differ from the boys in their performance on the Spatial