ASA 125th Meeting Ottawa 1993 May

2pMU4. Perceptual organization of speech signals: Clues from studies of sinewave replicas of utterances.

Robert E. Remez

Jennifer S. Pardo

Dept. of Psychol., Barnard College, 3009 Broadway, New York, NY 10027

Philip E. Rubin

Haskins Labs., New Haven, CT 06511

The perceptual organization of speech is a challenge for accounts proposing a two-stage model in which primitive auditory grouping is followed by schematic secondary processes. This difficulty stems from the diversity of acoustic constituents of speech signals, which is attributable in turn to the mechanics of vocal sound production. Primitive mechanisms that rely on similarity principles to group like elements therefore fail to parse the sound stream isomorphically to the sound sources. The insufficiency of primitive grouping mechanisms for organizing speech signals is often admitted, and knowledge-based latterly occurring processes are often invoked to explain the self-evident perceptual coherence of utterances. Studies with sinewave replicas of words and sentences show that phonetic perception occurs in conditions that thwart the application of primitive grouping mechanisms as they are presently understood. Psychophysical tests with sinewave words suggest that the perceptual organization of speech is distinct from other auditory organization. Because classic evidence and arguments discourage schema-based conceptualizations of phonetic processes, the two- stage model of organization appears to be implausible for speech. Perceptual organization of speech can better be rationalized by a phonetically specific facility that organizes and analyzes utterances. [Research supported by NIDCD and NICHD.]