Age-associated memory impairment of Logical Memory and Visual Reproduction.
The standardization sample from the WMS-III (weighted N = 1250) (The Psychological Corporation, 1997; Tulsky & Ledbetter, 2000), which varied in age from 16 to 89, was used to determine whether storage of verbal and spatial information was affected by normal aging. A previous study with the same sample using an analysis of variance approach showed that the age-associated deterioration for Logical Memory (LM) and Visual Reproduction (VR) delayed recall and recognition were comparable and largely explained by poor immediate recall. This led to the conclusion that age-associated memory impairment was due primarily to encoding deficits. However, that study did not control for the age-associated deterioration in immediate recall in order to ensure that the small age-associated effects for delayed recall and recognition were not confounded by the fact that the elderly had less to remember on the delayed recall and recognition trials. The current study used covariance analysis to statistically adjust the dependent measures, LM and VR delayed recall and recognition, based on immediate recall scores. These analyses showed that the age-associated changes in these measures were statistically significant, but the effect sizes were very small. Partial eta(2) for the main effect of age for LM was 0.06 with weak effect sizes for the interaction of recall type and age (0.02). The partial eta(2) for the main effect of age for VR was 0.09, and the interaction of recall type and age (0.04). This pattern of findings shows that after adjustment for immediate recall, LM and VR recall and recognition demonstrated comparable, slight declines with age suggesting that normal aging produced minimal changes in the ability to store new information when age-associated changes in initial encoding and retrieval were statistically controlled.