Spatial ability differences between males and females are widely acknowledged although controversy still exists over age of onset. Although it is commonly thought that such differences emerge during adolescence, this theory has been disputed. Two samples (normal children, average ages 13.7 and 13.4 years for males and females, respectively) were administered a complex spatial task. Performance was analyzed both quantitatively and qualitatively. Boys solved more problems, but even when they made errors, their answers were qualitatively more “abstract” that is, they showed a better and more effective visuospatial reasoning ability. These findings are discussed in light of sex‐differential cognitive styles also related to psychophysiological and environmental factors.