AGE, TARGET-DISTRACTOR SIMILARITY, AND VISUAL-SEARCH

Younger and older adults were asked to find a single target in both fe ature- and conjunction- search conditions. Display size varied between 2 and 8 items, and target-distracter similarity ranged from relativel y low to high levels. The accuracy data indicated that older adults ha d particular difficulty finding targets in high-similarity conjunction -search displays containing a large number of distracters. The reactio n time (RT) analyses found larger age deficits in many of these same c onditions. For both groups, predictions of conjunction search based on Treisman and Sate's additive model (Journal of Experimental Psycholog y: Human Perception and Performance, 1990: 16, 459-478) departed signi ficantly from actual performance. The RT data of older observers were, in large part, predicted as a simple linear function of the young adu lts' data. These results are discussed with respect to age differences in selective attention, generalized slowing, and an age-related loss in search efficiency.