Processing time, articulation time, and memory span.

In each of two experiments, measures of memory span, processing time, and articulation time were administered. One study involved 7- to 14-year-olds and adults living in the United States (N = 288); the other, 7- to 12-year-olds and adults living in Korea (N = 84). In both studies, the natural logarithm of age was correlated positively with measures of memory span but negatively with measures of processing and articulation times. Causal modeling indicated that age-related change in processing time is associated with a decrease in the time required to articulate numbers and letters, which determines memory span.