Aging, executive control, and attention - Verhaeghen & Cerella - 20020 - Article

Introduction

General slowing and its consequences for conclusions regarding age sensitivity of specific processes. It has long been known that reaction times of older adults can be well described by a linear transformation of reaction times of younger adults. The effect is called general slowing and is identifiable as the speed-of-processing deficit.

Analysis

The results of a series of meta-analyses is reviewed, examining age-related differences in selective attention (Stroop-task survey and negative-priming task survey) and in divided attention (dual-task survey and task-switching survey). The four task families all lent themselves to state trace analysis, in which performance in baseline conditions was contrasted with performance in experimental conditions separately for college-aged subjects and for elderly subjects.

Conclusions

Reviewing the five meta-analyses, a pattern in the age outcomes is apparent. At a concrete level, we found that specific deficits did not emerge in tasks that involved active selection of relevant information, such as determining the ink color of words (Stroop), in actively ignoring or inhibiting a stimulus (negative-priming), or in relinquishing attention from one aspect of the stimulus to reattach it to a different aspect (local task-switching). The selection requirement (Stroop) inflated central processing, but the degree of inflation was not greater in older adults than in younger adults.

Age deficits were found for dual-task performance and global task-switching. Unlike selective attention and local task-switching costs, dual-task and global task-switching costs were found to be additive in both young and old subjects, unmodulated by task difficulty. The switching added one or more additional processing stages to the processing stream. The cost was greater in older adults, but was limited to those experimental conditions that activated multiple task sets.