Processing speed and adult age differences in activity memory.

Immediate and delayed recall of performed cognitive activities was examined in 136 adults aged 20 to 85. Hierarchical regression analyses were used to assess the association between perceptual speed and age differences in activity memory. The age-related variance in delayed activity recall was reduced by 52% by the statistical control of perceptual speed, and the age-related variance in immediate activity recall was reduced by 91%. Thus, adult age differences in delayed and immediate activity memory were found to be associated with limitations in perceptual speed. The cognitive effort that is required to perform cognitive activities may tax the processing resources of older adults, prohibiting successful encoding of the activities.