EXAMINATION OF AGE-RELATED DEFICITS ON THE WISCONSIN CARD SORTING TEST

Adult age differences in Wisconsin Card Sorting Test (WCST) measures w ere examined before and after statistical control of age-related diffe rences in measures of feedback usage, working memory, and perceptual-c omparison speed, The proportion of age-related variance associated wit h a summary measure of WCST performance was greatly reduced after cont rolling for measures of feedback usage, working memory, and perceptual -comparison speed. Furthermore, the age-related variance associated wi th the feedback-usage measure was reduced after controlling for workin g memory and perceptual-comparison speed measures. These results are c onsistent with the idea that age-related performance differences in th e WCST are partially mediated by adult age differences in feedback usa ge and that age differences in feedback usage are mediated by age diff erences in working memory, which are in turn mediated by age-related r eductions in processing speed, indexed by measures of perceptual-compa rison speed.