Aging, digit span, and the stimulus suffix effect.

The first experiment showed that the amount of interference resulting from an extra auditory stimulus (stimulus suffix) placed at the end of a list of to-be-remembered items varied inversely with digit span in a sample of college students. In the second experiment suffix effects for a group of old subjects were of similar magnitude to those of young subjects with comparable spans. These results, along with others from our laboratory, indicate that explication of much of the influence of aging on short-term memory tasks reduces to factors determining memory span.