Contextual effects in the stimulus suffix paradigm

Morton & Chambers (1976) showed that the suffix effect - a selective impairment in serial recall on the final serial position of an acoustically presented list - was crucially affected by whether the suffix was a speech sound or a non-speech sound. They also claimed that the classification of a sound as speech-like was determined simply by the acoustic properties of the sound and not at all by the context. The crucial sound in their experiments was a steady state, naturally produced vowel sound which failed to give a suffix effect. We report here that when the sound was the only suffix used, it did produce a suffix effect. We conclude that, contrary to Morton & Chambers' conclusion, context effects are indeed operative in determining whether a sound produces a suffix effect.