The effects of age and sex on the factor structure of the Wechsler Memory Scale

Memory is one of the central intellectual functions characteristic of human behavior. Increasing age affects memory processes by requiring more time and increased learning trials in such tasks as memory for digits, symbols, and figures, and in the acquisition of new information. Factor analytic studies of the Wechsler Memory Scale (WMS) have been contradictory because of the confounding effects of subject age and sex. Principal component analyses with oblique rotations were performed 16 times on independent and random samples of males and females, and of males and females at each of three developmental age levels: 13-39, 40-59, and 60-88 years. For total male and female samples, a two-factor structure of general retentiveness and memory was found. For both males and females at 13-39 and 40-59 years, the same factor structure was obtained. The two-factor structure did not occur at age 60-88 for males or females. These findings confirm Wechsler's hypothesis as to the structure of the WMS, and Guilford's hypothesis as to the effect of age upon memory.