title: Age differences and interindividual variation in cognition in community-dwelling elderly.
abstract: The cognitive test performance of 897 community-dwelling elderly Ss, aged 70 years and over, was examined for age trends and interindividual variation. Data were subjected to factor analysis, and 3 factors emerged (Crystallized Intelligence, Fluid Intelligence, and Memory). Over the age span sampled, Crystallized Intelligence, Fluid Intelligence, and Memory all decreased with the decrease being greatest for Fluid Intelligence and least for Crystallized Intelligence. Interindividual variation increased for Fluid Intelligence and Memory, but not for Crystallized Intelligence. These findings give support to the view that crystallized intelligence is lower in the very old and that there is a greater degree of variability in test performance with advancing age.
authors.affiliation: National Health and Medical Research Council Social Psychiatry Research Unit, Australian National University, Canberra.
authors.forename: H
authors.initials: H
authors.lastname: Christensen
authors.forename: A
authors.initials: A
authors.lastname: Mackinnon
authors.forename: A F
authors.initials: AF
authors.lastname: Jorm
authors.forename: A S
authors.initials: AS
authors.lastname: Henderson
authors.forename: L R
authors.initials: LR
authors.lastname: Scott
authors.forename: A E
authors.initials: AE
authors.lastname: Korten
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology*; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000523:psychology*; D005260:Female; D006801:Humans; D007206:Individuality; D007361:Intelligence Tests / Q000706:statistics & numerical data*; D008297:Male; D011939:Mental Recall; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D011594:Psychometrics; D011597:Psychomotor Performance; D011930:Reaction Time; D015203:Reproducibility of Results