[The traits theory in longitudinal life span research. Partial report of a workshop]

During the international Workshop on 'Life Span and Change in a Gerontological Perspective' (9-12 July, 1981) at the University of Nijmegen, the Netherlands, research data from the Oakland Growth Study and the Guidance Study have been discussed. The second major contribution came from the longitudinal studies at the Bonn University. These groups of researchers cover different periods in the life span, but both contribute to prediction and understanding of periods not under investigation. Each of these longitudinal studies can contribute to the total understanding of the psychology of the life span. In this contribution we describe the trait-centered approach. The older research is mostly done with this theoretical approach in mind. We summarize the Californian studies and the Manhattan study on mental health. We close with some general critical remarks and we try to define the limitations of the trait-theoretical approach.