ADULT LIFE-SPAN CHANGES IN IMMEDIATE VISUAL MEMORY AND VERBAL INTELLIGENCE

A sample of 558 women and 1,163 men 17 to 102 years old, screened for neurodegenerative and neuropsychiatric disease, was administered tests of immediate visual memory (Benton Visual Retention Test) and crystal lized intelligence (Wechsler Adult Intelligence Scale Vocabulary subte st) from 1 to 5 times over 27.7 years. Cross-sectional and longitudina l evidence led to the conclusion that the 65-74-year decade was a wate rshed for decremental changes in immediate visual memory and verbal in telligence. Age accounted for considerably less variance in vocabulary than in immediate memory. The proportion of individuals whose longitu dinal trajectories were contrary to group trends decreased substantial ly with increased age; observed age changes remained when analyses wer e restricted to individuals who had perfect or near-perfect mental sta tus scores. Selected neuronal loss and slower reproduction times were considered as possible causes.