Acoustic Similarity, Letter String Length, and Their Effects on Ease of Recall

The capacity of short-term memory (STM) is not as simple as Miller's 7 +/- 2 paradigm (1956) and may be affected by the type of stimuli. In our study, we looked at the way acoustically-similar phonemes interacted with STM capacity using string length and a letter recall task. Forty-five students were read one set of acoustically-similar letter strings and one of acoustically-different strings, each containing three four-letter strings and three six-letter. Results for the interaction of sound and string length were t(44) = -6.25*, p<.05. Recall was lowest for acoustically-similar six-letter strings, evidence that STM capacity is decreased by acoustic similarity.

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