[The reversible share of cognitive deficits in older adults]

Cognitive performance of older adults is very often inferior to that of younger adults on a variety of laboratory tests assessing basic functions such as memory, inhibition, or attention. Classic hypotheses and theories share the idea that these cognitive deficits are irreversible, due to profound cerebral changes. In this review article, we develop a more positive conception of aging, according to which cognitive deficits are not all irreversible, and can even be partially if not completely reversible. To this end, we present some of the most illustrative research on the reversibility of the effects of aging on cognition. We show how subtle contextual manipulations can change older adults' motivation and strategy, which improve their cognitive performance. We also show that guidance toward the selection of the most appropriate strategy, whether explicit as in selectivity paradigms or implicit as in dual-task procedures, can increase older adults' cognitive performance. We finally describe the hypotheses and theories that both account for low cognitive performance in old age and ways to reverse the effects of cognitive aging.