Age differences in cognition in healthy educated men: a factor analysis of experimental measures.

Performance measures for a wide variety of cognitive laboratory tasks were factor analyzed, and the factors were identifiable as aspects of cognitive processing. The sample consisted of 96 healthy, educated men whose ages ranged from 20 to 80 yr. The factors were identified as speed of information processing, secondary memory, attention, and primary processing efficiency. Factor scores for each factor were correlated with age; r = -0.35, -0.30, -0.40, and -0.15 respectively, with better performance associated with lower age. The sample was divided into subsamples of 32 young (20-39), 32 middle (40-59), and 32 old (60-80) subjects; and each subsample was factor-analyzed separately to determine whether the factor structure was similar for all age groups. Evidence for factor-structure invariance with adult age was found in that all four factors in the primary analysis were identifiable in each of the age subsamples. The findings are consistent with a model of continual cognitive decline with age in healthy, educated adult males.