Sources of age -related retroactive interference in verbal working memory.

Interference has long been studied as mechanism of forgetting from primary (or working) memory, but evidence regarding age differences in interference in verbal working memory has been equivocal. Two major theoretical explanations for age-related declines in memory per se, source monitoring failures and inhibitory failures, lead to the direct prediction that older adults should be more susceptible to interference in working memory. Age-related increases in retroactive interference were predicted to occur in a recognition paradigm in which participants were required to study a list of word pairs, read an interfering list of pairs, and to distinguish among the lists. In two experiments, older adults were observed to exhibit disproportionate increases in retroactive interference when word pairs from an interfering read list had to be rejected. This age-related interference appeared to be primarily due to increased activation of the word pairs from the read list rather than to forgetting of the studied word pairs. Four related experiments were conducted to determine the relative contributions of source monitoring and inhibitory deficits to age-related susceptibility to interference. Limited evidence for inhibitory failures was observed using the process dissociation procedure, although such failures do not appear to account for the pattern of age-related interference. Increasing demands of source memory led to increased age-related interference, supporting the interpretation that source monitoring failures are the primary contributing mechanism to disproportionate increases in interference with aging. Additionally, individual differences were apparent in performance of older adults, with a fast subgroup of seniors performing as well as the young in some cases. Disproportionate age differences were confined to a slow subgroup of seniors at moderate levels of emphasis on source memory, while both subgroups demonstrated age-related decrements at higher levels of source memory emphasis.PhDCognitive psychologyExperimental psychologyPsychologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/127745/2/3029349.pd