Age , Target - Distractor Similarity , and Visual Search

Younger and older adults were asked to find a single target in both feature - and conjunction - search conditions . Display size varied between 2 and 8 items , and target - distractor similarity ranged from relatively low to high levels . The accuracy data indicated that older adults had partic ular difficulty finding targets in high - similarity conjunction - search dis plays containing a large number of distractors . The reaction time ( RT ) analyses found larger age deficits in many of these same conditions . For both groups , predictions of conjunction search based on Treisman and Sato's additive model (Journal of Experimental Psychology: Human Perception and Performance, 1990: 16, 459 - 478 ) departed significantly from actual performance . The RT data of older observers were , in large part , predicted as a simple linear function of the young adults' data . These results are discussed with respect to age differences in selective attention , generalized slowing , and an age - related loss in search efficiency .