The overall objective of the project is to investigate relationships between memory and intellectual functioning, utilizing age comparative factor analytic methods. Previous work with both longitudinal (Cunningham and Birren, 1980) and cross sectional work (Cunningham, 1980a; Cunningham, 1980b) indicate age changes in the structure of intellectual abilities. These changes in structure are primarily reflected in a greater interdependence of ability factors with age. The major hypothesis of the current study is that a slowing of speed of memory retrieval represents a fundamental limiting influence on intellectual performance in the elderly, in contrast to the young. Thus, it is expected that memory factors will be more highly correlated with ability factors in the elderly. However, it is hypothesized that if the ability interrelationships are partialed for the influence of the memory factors, the structures in the elderly will be significantly more similar to the young than the original factor covariance matrix. Such an outcome would be consistent with the idea that the previously observed age changes in factor structures may be explained by deficits in memory functioning. Concretely the project involves administering a carefully planned battery of ability and memory tasks to 150 young (ages 18 to 28) and 150 elderly subjects (ages 60 to 70). These data will be used to carry out comparative factor analyses and to apply factor partialling techniques, to evaluate the hypothesis indicated above.