Chapter VII: Intellectual Changes During Maturity and Old Age

Abstract

SINCE THE LAST REVIEW of this topic, most of the references in this area of study have been concerned with the results of intelligence tests in psychosis. Generally, the estimation of intellectual deterioration in abnormal states implies a correction for changes in score and in quality of intellectual performance as a function of age. The accumulation of evidence concerning intellectual changes in maturity and old age definitely indicates that as people grow older their test performances change. It is clear that intellectual changes as a function of age create problems concerning the interpretation of adult scores and adult intelligence quotients; the relationship of previous education, experiences, and skills to measurement of adult intelligence; the factorial composition of adult intelligence tests; the relationship of intelligence test scores in childhood and youth to such measures in adult populations; and the standardization and norming of adult intelligence tests. Perhaps the most significant new development is the demonstration that qualitative aspect of intellectual performance is fully as important as quantitative variations. ReviewsThe most significant review of the field is that of Brody (9) who reviewed some 230 references on intellectual change in normal and psychotic adult populations. Cattell (14) listed forty-four available adult intelligence tests indicating the technical handicaps in the estimation of adult intelligence and suggesting the difference between fluid and crystallized intelligence where fluid refers to relations between both new and old fundaments and crystallized to habitual responses. Miles (44) and Miles and Miles (45) gave a provocative survey of the psychology of the aging process. Bijou (7) reviewed nineteen references on the usefulness of the concept of test pattern, and Buxton (13) reviewed the status of research in reminiscence (improvement in recall without practice after original learning) indicating that no reliable evidence exists that reminiscence is related to age, sex, or intelligence of' the learner. Wechsler and the related discussion by Shakow (60) implied that intellectual changes parallel physical changes albeit the components used to measure intellectual changes decline at different rates, but that drive, persistence, and experience are significant aspects of intellectual performance.