Used the Spanish standardization of the Wechsler Adult Intelligence Scale III (WAIS III) (n=1,369) to test the age dedifferentiation hypothesis. Results show no changes in the percentage of variance accounted for by "g" and four group factors when restriction of range is controlled. Discusses an age indifferentation hypothesis. (SLD)

Examined age changes in intellectual ability in the range from 16 to 89 years through 2 studies that involved IQs on the Wechsler Adult Intelligence Scale III (WAIS-III). Results are interpreted in the context of the fluid-crystallized intelligence theory of J. Horn. Studies used WAIS-III standardization data for 2,450 adults and longitudinal data…

Whether cross-sectional rates of decline for brain volume and the Performance Intellectual Quotient of the Wechsler Adult Intelligence Scale-Revised were equivalent over the years 16 to 65 was studied with 196 volunteers. Results indicate remarkably similar rates of decline in perceptual-motor functions and aging brain volume loss. (SLD)

Three experiments investigated the possibility that adult age differences on block design tasks originate because of reduced efficiency with increased age in the cognitive processes associated with block manipulation. Older adults were substantially slower and less efficient than younger adults in performing tasks with minimized design…

Age differences in intellect as reflected in performance on the revised Wechsler Adult Intelligence Scale (WAIS-R) from age 20 to 74 years were evaluated for 1,480 adults from the WAIS-R standardization sample, while educational levels were held constant. Implications of the results for intelligence testing are discussed. (SLD)

First, third, fifth and eleventh graders were videotaped as they completed the Block Design Subtest of the WISC-R. Neither the order of placement of blocks within each design nor the degree to which children persisted in placing a given block correctly before moving to the next one evidenced developmental differences. (Author/RD)