Among the goals of this project are to describe adult age differences and changes in memory and learning performance and to investigate psychological processes underlying such age-related performance. This year, two procedures were devised to compare recall and recognition memory performance among age groups. A major difference in the task demands of recall and recognition involves item retrieval; i.e., items must be retrieved in recall but not in recognition. Conceptually, comparisons of recall and recognition performance among age groups should provide a test of the hypothesis that retrieval processes decline with age. Technically, however, there are problems in making such comparisons because the measurement scales are different. The two new procedures were applied to measures of number correct in delayed recall of unrelated words and a nonparametric index of detectability in delayed recognition of unrelated words. Both procedures yielded evidence for a retrieval deficit with aging in both men and women in the Baltimore Longitudinal Study of Aging (BLSA). Also this year, many measures (including immediate free recall, delayed free recall, delayed recognition memory, digit span, perception of dichotic pairs, vigilance, decision time, and vocabulary) were correlated with glucose tolerance in the women in the BLSA. When age, education, and obesity were taken into account, none of these measures was related to blood glucose concentration two hours after ingestion of a glucose load. The hypothesis that glucose regulation is related to memory performance was not supported by these data.
