Acoustic correlates of task load and stress

It is argued that reliable acoustic profiles of speech under stress can only be found if different types of stress are clearly distinguished and experimentally induced. We report first results of a study with 100 speakers from three language groups, using a computer-based induction procedure that allows distinguishing cognitive load due to task engagement from psychological stress. Findings show significant effects of load, and partly of stress, for speech rate, energy contour, F0, and spectral parameters. It is further suggested that the mean results for the complete sample of speakers do not reflect the amplitude of stress effects on the voice. Future research should isolate and focus on speakers for whom the psychological stress induction has been successful.