| Children and adolescents respond more slowly than young adults on a variety of information processing tasks. Three types of hypotheses have been proposed to account for these age-related differences. The global trend hypothesis posits that central processing speed changes as a function of age, and that, all component processes are changing at the same developmental rate (Kail, 1986b). The local trends hypothesis posits that different component processes are changing at different developmental rates (Bisanz, Danner, & Resnick, 1979). The strategic hypothesis posits that quantitative differences are attributable to qualitative differences in control processes. Gerontologists have advanced similar hypotheses concerning developmental changes in the speed of information processing in older adults (Salthouse, 1985). Recent evidence in cognitive aging supports the global trend hypothesis (Cerella, Poon, & Williams, 1980; Hale, Myerson, & Wagstaff, 1987).;The current effort examined the performance of three child groups (10-year-olds, 12-year-olds, and 15-year-olds) and a young adult group (mean age 19.6 years) on four different information processing tasks. An older adult group (mean age 69.3 years) was included in order to assess the hypothesis that the increase in response latencies observed in late adulthood is a mirror-image of the decreasing latencies observed during childhood.;Traditional ANOVA analyses of individual tasks supported the global trend hypothesis. Further support was found in analyses that integrated all four tasks revealing a single, precise linear relation between the latencies of each child or adolescent group and the young adult group. Thus, the latency of any child group was predictable from the latency of the young adult group on the same task, without regard to the specific componential makeup of that task. Finally, the relation between the older adult group and the young adult group was found to be positively accelerated. This finding suggests that the process responsible for the age-related decline in speed of processing during adulthood is not a mirror-image of the age-related increase observed during child development. |
