Attentional costs of mental operations in young and old adults

Abstract

Age changes in cognitive abilities are often attributed to age differences in controlled but not automatic processing. Very few studies, however, have independently evaluated the attentional demands or “cost” of both automatic and controlled mental processes in the same group of older adults. In this study, young adults (mean age = 25.5 years) and older adults (mean age = 66.5 years) rigorously screened for health status performed a primary visual match (same‐different) task, which was paired on some trials with a secondary auditory probe‐reaction time (RT) task. Probe RT was used as an independent measure of the attentional cost of the underlying component operations of the primary match task (stimulus encoding and matching and response selection). Both young and old groups demonstrated high accuracy rates for the matching task. The older participants showed significantly slower RT on the primary match task. They also showed greater probe RTs both for stimulus encoding, a presumably automatic mental operation, and for matching and response selection, presumably controlled or “effortful” operations. These findings were replicated and extended in a second experiment. The results demonstrate that older adults show increased attentional cost for both automatic and effortful mental operations compared to young adults.