How do Educational Attainment and Gender Relate to Fluid Intelligence, Crystallized Intelligence, and Academic Skills at Ages 22-90 Years?

Educational attainment and gender differences on fluid intelligence (Gf), crystallized intelligence (Gc), and academic skills in reading, math, and writing were analyzed for stratified adult samples ranging in age from 22 to 90 years. The data sources were the adult portions of the standardization samples of the second editions of Kaufman Brief Intelligence Test (N = 570) and the Kaufman Test of Educational Achievement-Brief Form (N = 555). Five univariate analysis of covariance were conducted with age as the covariate. Correlational analysis supplemented the covariate analyses to better understand the relationship of the five variables to education. All variables related significantly and substantially to years of formal schooling, an important finding in view of the key nature of this background variable for conducting neuropsychological assessments, as elaborated by Heaton and his colleagues. Surprisingly, Gf related just as strongly to education as did the school-related Gc. Among academic skill areas, math correlated higher with years of formal schooling than did either reading or writing. Women significantly outperformed men on the writing test and the reverse was true for the math test; other gender differences were not significant. These analyses fill a gap in the literature regarding the nature of gender and education differences in academic skills for heterogeneous samples of normal adults between young adulthood and old age and have practical implications for neuropsychological assessment.