Effects of repetition and response deadline on item recognition in young and older adults

In the present study, we examined the joint effects of aging, repetition, and response deadline in a plurality discrimination task. Young and older adults studied lists of unrelated singular and plural nouns, with half presented once (weak items) and half presented five times (strong items). Test lists contained old (same) nouns, plurality-reversed nouns (changed lures), and unstudied nouns (new lures), and the participants were asked to respond old only to same items. In Experiment 1, the participants were tested with both short and long deadlines. In Experiment 2, the tests were unpaced. In both experiments, repetition increased hit rates for young and older adults. Young adults tested with a long deadline or no deadline showed invariant (Experiment 1) or reduced (Experiment 2) false alarms to changed lures when the nouns were studied more often. Young adults tested with a short deadline and older adults tested with both long and short deadlines had increased false alarm rates for strong changed lures; without time pressure to respond, older adults did not have a significant increase in false alarms for changed lures. Implications of these results for theories of cognitive aging are explored.