An Evaluation of S pearman's H ypothesis by Manipulating g Saturation

S pearman's Hypothesis holds that the magnitude of mean W hite– B lack differences on cognitive tests covaries with the extent to which a test is saturated with g . This paper evaluates S pearman's H ypothesis by manipulating the g saturation of cognitive composites. Using a sample of 16,384 people from the General Aptitude Test Battery database, we show that one can decrease mean racial differences in a g test by altering the g saturation of the measure. Consistent with S pearman's Hypothesis, the g saturation of a test is positively and strongly related to the magnitude of W hite– B lack mean racial differences in test scores. We demonstrate that the reduction in mean racial differences accomplished by reducing the g saturation in a measure is obtained at the cost of lower validity and increased prediction errors. We recommend that g tests varying in mean racial differences be examined to determine if the S pearman's Hypothesis is a viable explanation for the results.