Impact of age, redundancy, and perceptual noise on visual search.

We examined adult age differences in the impact of redundancy and perceptual noise during visual search. Using a two-choice, visual search task, subjects responded to letters presented in one to four corners of an imaginary display square. On each trial, one, two, or three instances of a given target letter were presented. In the target-plus-noise condition, all nontarget corners of the imaginary square were filled with distractor (i.e., noise) letters. In the target-only condition, all nontarget corners were left blank. The results indicated that older adults showed relatively greater redundancy benefits than the young adults for the target-plus-noise trials than for the target-only trials. These results are interpreted within an internal noise framework.