Concepts of Intraindividual Variability and Change: Impressions of Cattell's Influence on Lifespan Development Psychology.

Raymond B. Cattell is not generally perceived to be a developmental psychologist. However, his lengthy, highly systematic research program produced many conceptual, methodological, measurement, and data analysis tools for identifying and studying interindividual differences and similarities in intraindividual change patterns. Such issues and methods are among the key elements of the foundation on which the lifespan orientation to the study of development rests. Therefore, one can see evidence of the integration of many of Cattell's contributions into the conduct of lifespan development research. In addition to conceptual and methodological innovations, Cattell's substantive contributions, including personality and ability concepts and their accompanying, age-graded measurement devices, are also utilized to varying degrees by developmentalists. How valuable for developmental research have Cattell's contributions been? The evidence sifted indicates that Cattell has not had a notable direct impact on traditional developmental research and theorizing, in part because he has not systematically invested his own efforts in the study of developmental phenomena and issues per se. At a more general level, however, and particularly in relation to the lifespan orientation to the study of development, Cattell's multivariate correlational research program is indeed helping to shape current direction and practice.