Aging and memory for frequency of occurrence of novel, visual stimuli: Direct and indirect measures

Standard tests of memory for frequency of occurrence require subjects to state explicitly how often a word occurred (absolute judgment) or which word occurred more often (relative judgment). Within this realm of research, the evidence is conflicting regarding the effects of age on memory for frequency of occurrence. The present studies examined further the effects of age on the ability to make relative judgments (i.e., "direct tests") regarding the frequency of occurrence of words and of novel, visual stimuli (Japanese ideograms). Moreover, young and old subjects were compared on indirect measures of memory for frequency of occurrence of these ideograms, as indexed by the mere exposure effect. Elderly and young subjects did not differ on the direct test of memory for frequency of occurrence of words, however elderly were impaired compared with young subjects when ideograms were presented. When tested indirectly, both groups were sensitive to the frequency of occurrence of ideograms. The pattern of results replicates and extends previous findings regarding performance dissociations between direct and indirect measures of memory in aging.