5aSC20. Modeling processing dependences in speech perception.

Session: Friday Morning, May 17

Author: Court S. Crowther
Location: Boys Town Natl. Res. Hospital, 555 N. 30th St., Omaha, NE 68131


The goal of this work was to determine whether acoustic cues to the phonetic features of a segment are processed independently. For stop--vowel (CV) syllables, one point of controversy concerns whether place information (as conveyed by formant transitions) and voicing information (as conveyed by VOT) are processed mutually independently. In this experiment, a replication of Massaro and Oden [J. Acoust. Soc. Am. 67, 996--1013 (1980)], F2 and F3 transitions and VOT were manipulated as place and voicing cues in CVs. Members of a family of multinomial models, including FLMP, were fitted to each subject's data. FLMP, which assumes that processing is independent at both the perceptual and decisional levels, failed to account for the data. Two other models retained the perceptual independence assumption, but one assumed the voicing decision was contingent on the outcome of the place decision, and the other assumed the opposite contingency. Both fitted better than FLMP, but nevertheless were rejected on statistical grounds. A model assuming decisional independence, but perceptual dependence, fitted each subject's data well. It was concluded that the formant transitions and VOT were not perceived independently, but that the voicing and place decisions were made independently. [Work supported by NIDCD (2-T32-DC-00013-16).]

from ASA 131st Meeting, Indianapolis, May 1996