Knowledge and executive control: Two factors that protect against age-related cognitive decline?

Various authors (Cattell 1963; Baltes 1987; Craik and Bialystok 2006, 2008) have proposed an interpretation of cognitive aging based on the distinction between two fundamental components: knowledge (or crystallized capacities), which remains relatively stable or increases throughout the life-span, and executive control (or fluid capacities), which declines during old age. This dichotomous interpretation of cognitive aging corresponds to what we here call “dual models of cognitive aging.” By comparing these cognitive theoretical models with neurocognitive models that aim to account for the neural mechanisms that protect against cognitive aging, we explore the hypothesis, on the basis of the literature on aging, that one or the other of the two components, (knowledge and executive control) could be a protective action against age-related cognitive decline.