The Relationship between Speech Rate and Memory Span in Children

Abstract

Evidence of a linear relationship between speech rate and memory span in children has been obtained in several studies (e.g. Hulme, Thomson, Muir, & Lawrence, 1984). This evidence is used to support an explanation of the development of memory span based on the working memory model (Baddeley, 1990). The model argues that speech rate is related to the amount recalled and that developmental increases in speech rate allow faster rehearsal with age and, hence, greater recall. However, the linear relationship between speech rate and memory span has generally been reported in terms of group means for speech rate and memory span rather than individual level correlations between the two variables. The present studies replicate the group relationship, but find that correlations between individual subject's speech rates and memory spans, when the effects of age are partialled out, are no longer significant. Nor was the size of the word length effect related to the difference in speech rate between short and long words. It is argued that the group mean relationship between speech rate and memory span is clear and replicable, but that the speech rates of individual children are not good predictors of those children's memory spans. The implications of these results for the working memory explanation of span development are discussed.