Age differences and similarities in the improvement of controlled search.

An age-related slowing of performance has been previously reported for tasks that require controlled search, an attention-demanding stimulus comparison procedure. In contrast, older adults have been found to resemble the young in the ability to improve search performance through the development of automatic detection, a comparison procedure that does not depend on attentional control. The present experiments examined the ability of young and older adults to improve controlled search performance under conditions designed to vary the attentional demands of search, but prevent the use of automatic detection. In both a pure memory-search task (Experiment 1) and a hybrid memory-search/visual-search task (Experiment 2), the overall rate of search was slower for the older subjects than for the young. The two age groups were similar, however, in their ability to use a familiar stimulus dimension (e.g., letter/digit) as a means of improving the rate of controlled search. The opportunity for reducing the attentional demands of the search task, rather than the use of automatic detection per se, thus appears to be a critical variable in determining older individuals' level of performance.