Adult age differences in multiple cognitive functions: differentiation, dedifferentiation, or process-specific change?

Adult age differences in covariance structures of latent variables of vocabulary, list recall, speed, working memory, and text recall, were analyzed to test hypotheses of structural changes with age. There were baseline data from 613 men and women aged 30-97, data from a second wave of testing from 322 people, and complete longitudinal data from 289 people. There were age differences in the size but not configuration of factor loadings cross-sectionally but not longitudinally. There were no changes in factor standard deviations or covariances. Findings did not support models of dedifferentiation with age.