Attempted decomposition of age-related influences on two tests of reasoning

Two studies were designed to determine which of several hypothesized compon ents were primarily responsible for the age-related effects on matrix reaso ning (Study 1) and analytical reasoning (Study 2), In neither case were the analyses successful because the variables selected to assess the hypothesi zed components failed to exhibit discriminant validity and also had little unique age-related influences. These results, along with the results of oth er analyses, suggest that large proportions of the age-related effects on d ifferent cognitive variables are shared and are not independent of one anot her. Implications of these findings for the interpretation of age-related i nfluences on measures of cognitive functioning are discussed.