Age Differences and Educational Attainment Across the Life Span on Three Generations of Wechsler Adult Scales

Patterns of maintenance of ability across the life span have been documented on tests of knowledge (Gc), as have patterns of steady decline on measures of reasoning (Gf/Gv), working memory (Gsm), and speed (Gs). Whether these patterns occur at the same rate for adults from different educational backgrounds has been debated. In addition, age-related research is needed to study global IQs, especially in view of the increased reliance on IQ in capital punishment court cases. In this study, large representative samples of adults tested during the standardizations of three versions of the Wechsler Adult Intelligence Scale (WAIS) served as subjects: WAIS-R (N = 1,480, ages 20-74), WAIS-III (N = 2,093, ages 20-90), and WAIS-IV (N = 1,800, ages 20-90). Based on regression analysis, patterns of aging on Full Scale IQ (FSIQ) and the four abilities (a) were essentially the same for males versus females and (b) characterized all levels of education across three generations of Wechsler’s adult scales.