Concept generation: validation of a test of executive functioning in a normal aging population.

A new test, Concept Generation, was designed to fractionate the processes that underlie sorting performance in an efficient paper-and-pencil format. The test was administered to 60 subjects, aged 18-79. Results indicated age-related deficits for self-initiated concept formation, shifting set, output monitoring, and perseverative tendencies. When cuing was introduced to increase structure, age group differences were attenuated or eliminated. Within the older group, subgroups were identified based upon the nature of their repetitions. The hypothesis that sorting behavior is mediated by executive functions led to correlational analyses between Concept Generation scores and other measures of executive functioning. The pattern of correlations supported the construct validity of the Concept Generation test. In addition to providing preliminary evidence for the usefulness of Concept Generation in executive functioning assessment, the results replicated and extended previous work on executive functioning in older individuals.