Adaptation of phonetic feature analyzers for place of articulation.

Abstract

A series of experiments was conducted to determine the effects of selective adaptation on the perception of linguistic feature contrasts. The test stimulus consisted of a series of synthetic speech sounds, 13 CV syllables which varied in the starting frequency and direction of second- and third-formant transitions. Variations in these formant transitions are sufficient for the perceived consonant distinctions along what linguists have termed the place of articulation dimension; in this case, the perceived distinctions were among the syllables [b æ], [d æ], and [g æ]. It was found that a significant adaptation effect could be obtained for the feature place, as measured by both identification and discrimination responses. For various adapting stimuli, alterations in perception occurred, such that test stimuli lying near a phonetic boundary, normally perceived as having the same place value as the adapting stimulus, were perceived after adaptation as having a systematically different place value. In addition, the effectiveness of a real speech adapting stimulus [bi], for which the second- and third-formant transitions differed from those of the test stimuli, suggested that adaptation for the feature place operates primarily at a site of phonetic, as opposed to acoustic, feature analysis. Characteristics of this feature analysis site are proposed in light of the obtained perceptual shifts.