Die Sorge für und um andere Menschen als bedeutsames Motiv des hohen Alters – ein Beitrag zum Verständnis des zoon politikon echon

We review research findings on the oldest old that demonstrate that the fourth age entails a level of biocultural incompleteness, vulnerability and unpredictability that is distinct from the positive views of the third age (young old). The oldest old are at the limits of their functional capacity and science and social policy are constrained in terms of intervention. New theoretical and practical endeavors are required to deal with the challenges of increased numbers of the oldest old and the associated prevalence of frailty and forms of psychological mortality (e.g., loss of identity, psychological autonomy and a sense of control). Investigation of the fourth age is a new and challenging interdisciplinary research territory. Future study and discussion should focus on the critical question of whether the continuing major investments into extending the life span into the fourth age actually reduce the opportunities of an increasing number of people to live and die in dignity.

Does plasticity contribute to adult cognitive development, and if so, in what ways? The vague and overused concept of plasticity makes these controversial questions difficult to answer. In this article, we refine the notion of adult cognitive plasticity and sharpen its conceptual distinctiveness. According to our framework, adult cognitive plasticity is driven by a prolonged mismatch between functional organismic supplies and environmental demands and denotes the brain's capacity for anatomically implementing reactive changes in behavioral flexibility (i.e., the possible range of performance and function). We distinguish between 2 interconnected but distinct cognitive outcomes of adult cognitive plasticity: alterations in processing efficiency and alterations in representations. We demonstrate the usefulness of our framework in evaluating and interpreting (a) increments in frontal brain activations in the course of normal aging and (b) the effects of cognitive training in adulthood and old age. Finally, we outline new research questions and predictions generated by the present framework and recommend design features for future cognitive-training studies.