“…The matrices tasks, including the Matrix Reasoning subtest added to the third edition of the WAIS (WAIS-III; Wechsler, 1997), showed mean scores that declined substantially with age from the early 20s to late 80s, using educationadjusted cross-sectional samples (A. S. Kaufman, 2000;Wang & Kaufman, 1993); the WJ-R cluster demonstrated the classic pattern of substantial decline from ages 20 to 75 based on McArdle et al's (2002) use of the latent growth technique and longitudinal data. Other studies by Horn (1985), his colleagues (Horn & Donaldson, 1980;Horn & Hofer, 1992), and other researchers (e.g., Babcock, 1994;Beier & Ackerman, 2005;Bromley, 1991;Finkel, Reynolds, McArdle, Gatz, & Pederson, 2003;Wahlin, MacDonald, deFrias, Nilsson, & Dixon, 2006) have featured fairly pure measures of Gf such as matrices, letter series, number series, figure logic, card sorting, and figure classification. These studies consistently identified characteristic patterns of Gf decline, although the samples were invariably smaller, less stratified, and covered a smaller portion of the adult life span than studies such as the ones cited (e.g., McArdle et al, 2002) that utilized large, stratified samples of adults across the broad adult lifespan.…”