The dumbledore hypothesis of cognitive aging

Cognitive aging is often characterized as a process in which two competing forces determine individual development: a genetically driven senescence process that engenders declines in mental mechanics; and an accumulation of life experience that augments cultural, pragmatic, and knowledge-based competence. The considerable variability in the level and rate of change in complex intellectual activities (e.g., language understanding) is often accounted for in terms of individual differences in abilities associated with these forces. I argue that choice in how effort is allocated may be an essential determinant of cognitive change over the life span - both directly, in the form of attentional engagement, and indirectly, as it sculpts neural substrates that give rise to component abilities.