Contextual effects in the stimulus suffix paradigm

Abstract

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.

Capturing the suffix: Cognitive streaming in immediate serial recall.

“…Early in suffix research, Morton et al (1971) established that the acoustic context was important: The magnitude of the effect of some manipulations of the suffix (such as ear of presentation) depended very heavily on what other manipulations were being experienced by the participant (a conclusion whose generality was further reinforced by Ottley, Marcus, & Morton, 1982). One possible explanation of the Ayres et al (1979) result is that "wa" is perceived as a musical sound regardless of the context, and that its appearance in experimental trials with stimuli that are unambiguously speech shows some kind of contrast effect.…”

The context-dependent stimulus suffix effect.

“…The second line of evidence is that the potency of a token to function as a suffix depends on the context in which it is perceived; this is contrary to the precategorical nature of the store. Whereas the former finding has been widely replicated, this latter finding has been convincingly demonstrated in the literature only once (Ayres, Jonides, Reitman, Egan, & Howard, 1979), although Ottley, Marcus, and Morton (1982) presented evidence consistent with this idea. Ayres et al (1979) challenged the precategorical interpretation by reporting an experiment in which the same, acoustically identical suffix reduced recall of the final item only when it was interpreted as human speech; when interpreted as a musical sound, this suffix did not affect recall.…”

“…The interesting result was that the ambiguous wa sound functioned as speech for the speech group and as nonspeech for the music group; that is, the effectiveness of the suffix was dependent on how the subjects were led to interpret it. Ottley et al (1982) reported an experiment designed originally to investigate an unusual observation by Morton and Chambers (1976). These latter researchers had used as a suffix a portion of a steady state vowel ah that they termed AH 1.…”

Two-component theory of the suffix effect: Contrary evidence

“…Also, the effect on recall of the final item is attenuated if the item is synonymous with the suffix (Salter & Colley, 1977). Each of these findings has been replicated (see Neath, Surprenant, & Crowder, 1993;Ottley, Marcus, & Morton, 1982) and is inconsistent with the two-component theory.…”