Sex, sports, and hormones: A case for space?

The present study explored biological and experiential factors contributing to individual differences in spatial ability by investigating performance differences relating to sex, athleticism, and 2D:AD ratios, a marker of fetal testosterone and estrogen levels, on allocentric and egocentric measures of spatial ability. Men were more accurate than women on a Shepard & Metzler-type mental rotation task and significantly faster when making right-left identifications of asymmetrical everyday objects (e.g., hands, shoes). There were no sex differences on the egocentric Semmes Body task, the body mental rotation task, or the Phonological and Semantic Verbal Fluency tasks. Men had significantly lower 2D:AD ratios than women, indicative of high fetal testosterone relative to low fetal estrogen. Among men, low 2D:AD ratios correlated with greater accuracy on the Right-Left Differentiation task, whereas high 2D:AD ratios (i.e., indicating low fetal testosterone relative to fetal estrogen) correlated with faster mental rotation speed, supporting assertions that fetal testosterone in the low male range is optimal for allocentric spatial ability. Among women, high 2D:AD ratios correlated with better performance on both verbal fluency tasks. While athletes were significantly more accurate when dealing with parts of their own bodies (Semmes Body task) and making right-left determinations, they were not better on either mental rotation task. Correlations between 2D:AD ratios and athletic achievement revealed that lower 2D:AD ratios correlated with a higher level of athletic achievement in both men and women. Our findings suggest that higher prenatal testosterone may be predictive of better athletic ability in both sexes and might be related to greater skill in activities requiring egocentric spatial transformations among men. Whether the improved spatial abilities are the result of increased athletic experiences or are aptitudes that lead individuals to pursue and excel in sports, remains for future investigation.