COMPONENT PROCESSES OF MEMORY - CHANGES ACROSS THE ADULT LIFE-SPAN

What abilities or skills need to be recruited for free recall of a list of words, to what extent do they influence performance, and does their influence remain constant across the lifespan? These and related questions were addressed in an investigation with 163 community dwelling healthy adults. In a session that lasted about 2.5 hours, each participant received a battery of tests, including the Rey Auditory Verbal Learning Test (RAVLT), and the North American Adult Reading Test (NAART). We also assessed age-changes in motor-speed - by means of a finger tapping test, processing-rate - by means of the speed of reactions to a simple stimulus, and processing-capacity - by means of a card sorting task. The results show age-declines in the scores on all tests, except on the NAART. More detailed analysis of RAVLT performance showed age-related declines only on the primacy and middle portion of recall, but not on the recency portion. Structural equation modeling showed that aging was associated with a decline on all three components of speed, and more importantly, that processing-rate and -capacity make distinct contributions to episodic memory test performance. The latter finding underscores the fact that speed is made-up of dissociable components.