Tone perception cues: Pitch targets, trajectories, or both?

Abstract

Zsiga and Nitisaroj [(2007)] conducted tone perception experiments to test the Moren and Zsiga [(2006)] hypothesis that the principal perceptual cues to the five-way tonal contrast in Thai are high (H) and low (L) pitch targets aligned to (subsyllabic) moras. Their experiments involved perception of synthetic stimuli: manipulated peaks or troughs (corresponding to pitch targets) connected by line-trajectories. In the present study, the stimuli created are intended to be more naturalistic. The hypothesis is that not only peaks and troughs but also the trajectories between them are informative to and important for perception. Manipulations involve realignment of the peaks and troughs, with concomitant compression or expansion of the original trajectory between them. Native Thai speakers categorize the manipulated tone and give a goodness rating. Preliminary data indicate that some categorizations (e.g., manipulated rising perceived as high) can be explained by information present in the trajectory, and not in the peak/trough. However, theories that advocate movements (i.e., trajectories) as perceptual cues [e.g., Xu (2004)] cannot account for some goodness ratings observed in these experiments. Hence, it appears that a combination of the peak/trough information, as well as the trajectory, is employed in tone perception. Work supported by Dr. Luigi Burzio and Dr. Colin Wilson.