Processing consequences of perceptual grouping in selective attention.

Two experiments examined adult age differences in the effects of perceptual grouping on attentional performance. In a search task, 48 young, middle-aged, and elderly subjects sorted cards based on the orientation of a target figure. The interfering effects of irrelevant information which did or did not contrast with the target in orientation were examined. The position of targets varied from one card to the next. Elderly, but not young or middle-aged subjects were slowed by the presence of contrasting irrelevant information. All three age groups were slowed by the presence of similar irrelevant information, but the elderly were slowed more than the young adults. A similar procedure was used in a second experiment, but the position of targets within each deck did not vary from one card to the next. No age group was slowed by the presence of contrasting irrelevant information, and only the elderly were slowed by the presence of similar irrelevant information. The importance of perceptual grouping in accounting for adult age-differences in attentional processes was discussed.