An Individual Differences Perspective: Implications for Cognitive Research in Gerontology

Abstract

This article sketches the fundamental characteristics of an individual differences orientation to gerontological research, with particular reference to adult cognitive development. It is shown that cross-sectional differences in variances and covariances often reported in the gerontological literature are consistent with the hypothesis of individual differences in patterns of change. However, different covariance structures at different cross-sectional age levels are also consistent with the hypothesis that the constructs being measured are qualitatively different at different ages. Longitudinal research explicitly measuring individual differences in change is required to differentiate between the two classes of hypotheses. The article outlines the general features of a research strategy that employs longitudinal designs and structural equation models to examine patterns and predictors of individual differences in adult cognitive development.