Age differences in primary organization or processing variability? Part II: Evidence for processing variability

Young and older adults were compared on their ability to organize letter sets into "opaque" memory codes (letters were either transposed within or between imposed chunk boundaries on a secondary memory, recognition task). Also, processing variability (i.e., internal noise) was examined via signal detection methods. The data indicated that there were no qualitative age differences in the manner in which both groups organized opaque memory codes, although older adults did take significantly longer to respond. The results from the signal detection theory portion of the present experiment demonstrated that older adults' memory operating characteristic curves exhibited significantly more variability than those of the young. This suggested that an age difference in processing variability existed, rather than any appreciable age difference in the primary organization (i.e., the forming of opaque memory codes) of item order information.