Adult age differences in strategy use during verbal fluency performance.

This study investigated adult age differences in strategy use during verbal fluency performance among 60 older and 60 younger adults. Clustering and switching, strategic components of fluency, were investigated as predictors of performance along with cognitive processes thought to underlie these strategies, namely verbal ability, speed of processing and executive function (strategic planning, performance monitoring, etc.). Two measures of verbal fluency were used: initial and excluded letter (words produced not containing a designated letter). These tasks both require search for words based on a phonemic cue but are thought to reflect a differential reliance on strategic retrieval search processes for successful performance. The number of clusters produced accounted for age differences in excluded, but not initial, letter fluency. Performance on both fluency tasks was associated with the number of clusters and switches participants produced and initial letter fluency was associated with cluster size for older adults and a ratio index of effective search for both age groups. In general, both fluency tasks relied on verbal ability and articulation speed, and excluded letter fluency performance relied more on speed and executive function than did initial letter fluency, especially for older adults.