Phonological Similarity, Pronunciation Rate, and Memory Span

Memory span is smaller for (a) items taking longer to pronounce and (b) phonologically more similar items. We investigated the relation between the two effects. Chase (1977) found that phonologically similar items were pronounced more slowly than dissimilar ones in a pronunciation task. A pronunciation rate difference in immediate recall could explain the phonological similarity effect as a special case of the word-length effect. Instead, the study found that pronunciation rates were equal. In the equation s = rt, span equals pronunciation rate times trace duration, word-length affects r while phonological similarity affects t. The two effects are shown to be complementary.