Are articulations integrated in the perception of vowel height?

Abstract

Using the Garner paraidgm [W. Garner (1974)], Kingston [Phonetica (in press)] demonstrated that the acoustic effects of differences in velum height (the frequency separation of the nasal pole and zero =nasalization) and rate of vocal fold vibration (fundamental frequency) which covary with tongue height in vowels are integrated perceptually with the acoustic effect of that articulation (first formant frequency), perhaps because they exaggerate the perceptual value of the latter articulation. The failure to separate perceptually the acoustic effects of these three articulations challenges the claim of direct realists [e.g., C. Fowler, J. Phonet. 14, 3–28 (1986)] that articulatory gestures are the objects of speech perception, but in only a limited way, since the stimuli were brief and simple enough that they may not have allowed listeners to attribute these acoustic effects appropriately to their articulatory sources. Experiments are currently in progress to test whether similar perceptual integration occurs even when other aspects of the stimuli would allow the acoustic effects to be attributed to coarticulation [R. Krakow et al., J. Acoust. Soc. Am. 83, 1146–1158 (1988)], e.g., is nasalization integrated with first formant frequency in nasal as well as oral consonant contexts? Integration will also be tested more rigorously than in the earlier work, using precepts of signal detection theory.