The Relationship between Memory Span and Processing Speed

For any individual, processing speed, as reflected by reading rate, varies for words of different lengths, and the rate of increase of memory span as a function of reading rate yields an index of memory capacity. A study of memory span in 8, 10 and 12 year old children, using these direct measures of processing efficiency and memory capacity, indicated that the developmental increase in memory span is attributable wholly to the increase in mean reading rate. For all age groups, a subject’s memory span for a given set of words was roughly equal to how many of the words the subject could read in two seconds. Furthermore, for any given reading rate, the memory span was independent of age.