Evaluating Cognitive Dedifferentiation

The age dedifferentiation hypothesis for cognition predicts that different cognitive abilities are more closely interrelated in older than in younger adults. However, extensive research on this topic has failed to produce a consensus on the size of this effect and even whether it occurs, possibly due to the large number of methodological and theoretical differences between studies. The present data sets used norming data from six cognitive batteries and several sets of longitudinal data to evaluate whether dedifferentiation occurs in representative, healthy aging samples ranging in mean age from 16-99. In addition, we evaluated whether factors like test battery, the type of cognitive ability being measured, or the type of age trajectory tested impacts whether age dedifferentiation was found.