An analysis of the effect of aging on recognition memory

The effect of aging on recognition memory processing is analyzed in terms of a stimulus-sampling model of recognition memory with parameters representing encoding effectiveness and stimulus overlap or interference. A standard study-test paradigm with a 2-alternative-forced-choice test was used with older and younger adults. While no significant difference in accuracy between groups was observed, it was found that the distribution of recognition scores for older adults was bimodal with an upper mode which did not differ from the younger group and a lower mode representing a large decrement in performance. For those adults who showed recognition deficity with aging, analysis in terms of the model revealed reduced encoding effectiveness. Recognition performance of the older adults was strongly related to verbal ability as measured by the WAIS vocabulary subtest. Disparate results of recognition studies in the aging literature are discussed in terms of variations in verbal ability among the groups studied.