Intraindividual variability in performance as a theoretical window onto cognitive aging

Abstract This chapter makes a case for considering intraindividual differences in performance across tasks (dispersion) and intraindividual variability across occasions (inconsistency), in addition to mean level of performance, in characterizing groups and developing theoretical accounts of group differences and developmental trajectories. It reviews evidence that measures of intraindividual differences in variability tend to be stable over time and domains.