Perception of back vowels: effects of varying F1 - F0 Bark distance

In a study of vowel height perception using front vowels, Hoemeke and Diehl [J. Acoust. Soc. Am. 96, 661-674 (1994)] found that F1 - F0 distance was the best predictor of perceived vowel height for the phonological distinction [+/- high], while for two other vowel height distinctions F1 alone was the best predictor. Further, the [+/- high] identification function was defined by a sharp boundary located at 3- to 3.5-Bark F1 - F0 distance. One hypothesis offered was that F1 - F0 distance had cue value for the [+/- high] distinction because of an underlying quantal region on the F1 - F0 distance dimension. However, the results are also predicted if it is supposed that F1 - F0 distance is a cue for vowel height only for pure height distinctions. The present study further tested these possibilities, using back vowels. The results allowed us to reject both as general explanations of vowel height perception. However, the results were consistent with a third possible explanation, namely, that phonetic quality is determined by the tonotopic distances between any adjacent spectral peaks (e.g., F3 - F2, F2 - F1, and F1 - F0), with greater perceptual weight accorded to smaller distances.