Exploring dedifferentiation across the adult lifespan.

One of the central concepts within the literature on cognitive aging is the notion of dedifferentiation-the idea that increasing age is associated with an increase in the interrelatedness of different cognitive abilities. Despite the centrality of this dedifferentiation hypothesis, there is a great deal of evidence that both supports and does not support dedifferentiation. We hypothesized that these inconsistent findings were due to (a) the use...