PhD, University of Alberta (Canada)
Speech Perception and Psychoacoustics
Peter Assmann received a Bachelor's degree in Psychology and Philosophy from the University of Waterloo in 1976, followed by an MSc (1979) and PhD (1985) in Linguistics from the University of Alberta. He subsequently completed 3 years of postdoctoral research in speech and hearing science at the Medical Research Council Institute of Hearing Research in Nottingham from 1985 to 1988. He joined the faculty at UT Dallas in 1989. He served as Associate Editor for the Journal of the Acoustical Society (Speech Communication) from 2002-2005 and is a Fellow of the Acoustical Society of America.
My research investigates the perceptual strategies used by listeners to recognize speech. Speech communication has an extraordinary resistance to distortion: intelligibility is preserved when a substantial portion of the spectrum is eliminated by filtering, when large segments of the waveform are deleted or replaced by silence, or when the signal is embedded in background noise. Research in my lab has centered on a series of experimental investigations of the distortions introduced by competing voices, narrow bandpass filtering, spectral flattening, local time reversal, and frequency scaling. We are evaluating theoretical and computational models of speech perception to account for the extraordinary resilience of human speech communication to such distortions. Our studies of frequency-scaled speech have revealed the operation of perceptual mechanisms that help listeners cope with the enormous variability in the acoustic patterns of speech across talkers. Much of this variability is a direct consequence of size differences in the larynx and vocal tract as a function of age and sex.
Supported by a grant from the National Science Foundation, we are studying the detailed pattern of these changes in a database of speech recordings from adults and children ranging in age from 5 to 18 years. These recordings provide materials for constructing stimuli in listening experiments, acoustic parameters for realistic voice synthesis and voice conversion, and normative data for studies of speech perception and production in adults and children. This project is providing valuable information on the nature of speech development and the acoustic scaling transformations that take place as children grow into adults. Acoustic measurements from the recorded samples are incorporated into statistical pattern recognition models to predict the responses of listeners to natural and synthesized speech. These models provide a basis for testing and refining hypotheses about the perceptual transformations that listeners apply to cope with acoustic variability, and the processes by which they extract phonetic and indexical information in speech perception.
Sullivan. J, Thibodeau, L., and Assmann, P.F. (2013). Auditory training in interrupted noise improves speech recognition in noise for children with hearing impairment. Journal of the Acoustical Society of America 133: 495-501.
Hubbard D. and Assmann P.F. (2013). Perceptual adaptation to gender and expressive properties in speech: The role of fundamental frequency. Journal of the Acoustical Society of America 133: 2367-2376.
Morrison, G.S., & Assmann, P.F. (Eds.) (2013). Vowel inherent spectral change. Heidelberg, Germany: Springer-Verlag.