WAIS–R aging patterns were examined for a group of 200 psychiatric inpatients. Inpatients were grouped into six age categories: less than 24, 24–28, 29–32, 33–38, 39–43, and greater than 43 years. Verbal and Performance sums of scaled score, subtest scaled score, and raw score total, and individual item score means were examined for each age category. The classical aging pattern was observed wherein more crystallized cognitive abilities remained stable over age groups of the life span while more fluid abilities dropped sharply with their increasing ages. Results supported the decline in fluid cognitive abilities hypothesis for WAIS–R aging patterns advocated by Horn in 1985 and Kaufman in 1990.
