The g factor

Arthur Jensen has systematically developed a seminal concept first discovered by Charles Spearman in the 1920s: individual and group differences in mental ability exist, and these differences can be measured by a single, general factor, g. On its surface, this concept seems innocuous. However, Jensen does not draw back from its most controversial conclusions - that the average differences in IQ and other abilities found between sexes and racial groups have a substantial hereditary component, and that these differences have important societal consequences. The culmination of his career is the…