Age, target-distractor similarity, and visual search

Younger and older adults were asked to nd 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 nding targets in high-similarity conjunction-search dis-plays containing a large number of distractors. The reaction time (RT) analyses found larger age decits 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 signicantly 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 di erences in select ive attention, generalized slowing, and an age-related loss in search efficiency