T10 Perception of dynamic pitch in speech
The perception of dynamic – constantly changing – pitch in speech has been extensively studied in psychoacoustics and linguistics. In psychoacoustic studies, listeners are usually presented with short stimuli such as vowels or syllables, and their ability to discriminate a pair of stimuli is assessed. On the other hand, linguistic studies concern intonation over an utterance. Intonation entails not only acoustic prominence realised by pitch, duration, and loudness, but also listeners’ abstract knowledge about the relative prominence between syllables within a word or between words within an utterance.
Assuming that listeners’ important task in speech communication is to allocate their attention to high-information sites in an utterance or over utterances, the linguistic approach has higher ecological validity than the psychoacoustic approach. But previous linguistic studies have limitations. First, many of them used psychoacoustic tasks, asking listeners to listen to pitch, rather than the intonational prominence. Second, the vast majority of them tested the perception of only pitch peaks (rise-falls), neglecting valleys (fall-rises). Third, participants were limited to young listeners speaking a standard dialect of the target language.
This talk will discuss a research project addressing these issues. In our experiments, we used both psychoacoustic and linguistic tasks; participants judged either relative pitch height or prominence between two pitch peaks or valleys in an utterance. Native English speakers in different age and dialect groups were tested. Outcomes indicate that first, listeners’ pitch height discrimination in the utterance context seems to be more accurate than what previous studies report. Second, there is a robust perceptual asymmetry between pitch peaks and valleys, the valleys posing significant challenges as shown for both psychoacoustic and linguistic tasks. Third, listeners’ perception of pitch height and prominence is disassociated. The findings taken together suggest an intricate interaction between the physical properties of the stimuli and listeners’ top-down knowledge in the perception of speech intonation.