Cumulative deficit is an hypothesis concerning the cause of lower mental test scores of groups considered environmentally deprived. It presupposes a progressive decrement in test scores, relative to population norms, as a function of age. Clarification of the theoretical issues and the methodological problems involved in establishing the…

Jensen (1985) caused us to reexamine earlier findings. After correcting perceptual efficiency and executive systems measures for unreliability, original conclusions remain tenable. Control processes are factors in understanding race-related differences in intelligence. We do not deny the association of "speediness" but argue for a multidimensional…