Components of integrality in the perception of voice quality and tongue root position

Abstract

Vowels in this study varied in voice quality and tongue root position. Crosslinguistically, a lax voice quality typically co-occurs with advanced tongue root, whereas a tenser voice quality cooccurs with nonadvanced tongue root. Both articulations concentrate energy at low frequencies: laxing the voice increases the relative prominence of the first harmonic, and advancing the tongue root lowers F1. The Garner paradigm was used to test, for vowels in CVC context, whether these acoustically similar effects also integrate perceptually. Detection theory was used to assess the degree and type of perceptual integration. Meanintegrality (the mapping of harmonic amplitude and F1 onto a common perceptual dimension) was inferred by comparing two-stimulus classification tasks in which stimuli differed on either one or two dimensions. Varianceintegrality (an increase in perceptual uncertainty) was inferred by comparing classification and identification tasks with and without irrelevant variation. The source of variance integrality (sensory or context memory [Durlach etal., Percept. Psychophys. 46, 293–296 (1989)]) was determined by comparing the two-response Garner tasks with conditions using more than two stimuli and responses. [Work supported by NSF and NIH.]