Age-related slowing in memory search for three-dimensional objects.

Abstract

Old (M = 68.9 years) and young (M = 21.3 years) adults were presented with a memory search task in which stimulus sets consisting of small statues were either categorically mixed or categorically distinct. Memory set size (two, three, or four statues) was varied across trial blocks as was target/distractor status of the sets. A significant linear effect of set size was obtained for both old and young adults in the categorically mixed condition. Search rates for old persons in this condition were slower than for young persons. Search rates of old and young persons did not differ, however, when stimulus sets were categorically distinct, and the set size effect was eliminated in this condition as both age groups evidenced essentially zero slope values over varying memory set sizes. Results were supportive of the complexity hypothesis of age-related slowing in that old persons' response times in the various experimental conditions were a monotonically increasing function of young persons' response times.