Memory and metamemory performance in older adults: one deficit or two?

In two separate experiments, three groups of older adults (50-80 years old) were shown lists of forename-surname pairs. At test subjects were cued with the surname and asked whether they knew the forename (prospective evaluation). Subjects attempted recall for those items they claimed to know and rated their confidence in their answer (retrospective evaluation). In Experiment 1 subjects saw the name list on 5 successive occasions and attempted recall after each. The older subjects recalled fewer items, but there were no age differences on retrospective memory evaluation. There was a marginally significant age effect on the prospective memory evaluation, which on closer inspection appeared to be a scaling effect related to recall performance. Experiment 2 verified this conclusion in a sample of older adults taking part in a training study extended over many weeks. The main implication of this work is that studies that compare metamemory accuracy in groups that differ in baseline memory performance should be careful before drawing conclusions about metamemory independently of memory performance.