Franz E. Weinert, Wolfgang Schneider, Monika Knopf

• Experimental research on memory development has typically focused on the description of universal development trends across the life span and the identification of major sources of development within this domain. However, there is a lack of studies investigating the preconditions and effects of interindividual variability within age groups across different memory tasks. Similarly, our knowledge about the stability of interindividual differences across the life span as well as the sources and the amount of intraindividual variability acrossExperimental research on memory development has typically focused on the description of universal development trends across the life span and the identification of major sources of development within this domain. However, there is a lack of studies investigating the preconditions and effects of interindividual variability within age groups across different memory tasks. Similarly, our knowledge about the stability of interindividual differences across the life span as well as the sources and the amount of intraindividual variability across memory tasks is scarce. In the present chapter, we concentrate on these neglected issues. First, theoretical assumptions concerning the interindividual and intraindividual variability of memory development are discussed. Next, empirical evidence is presented that seems suited to document the importance of these neglected issues. While we try to give a representative account of the literature, the emphasis is on more recent studies of memory development in children and elderly adults conducted in our laboratory. The results demonstrate that age-related changes and individual differences in the knowledge base are particularly important for describing and explaining individual differences in memory develoment. In comparison, the rote of stable individual differences in basic memory capacities in explaining variations in memory development is less clear given tbe conflicting empirical evidence. In the final section of the chapter consequences for future research are discussed.…