Perceptual susceptibility to acoustic manipulations in speaker discrimination

Listeners' ability to discriminate unfamiliar voices is often susceptible to the effects of manipulations of acoustic characteristics of the utterances. This vulnerability was quantified within a task in which participants determined if two utterances were spoken by the same or different speakers. Results of this task were analyzed in relation to a set of historical and novel parameters in order to hypothesize the role of those parameters in the decision process. Listener performance was first measured in a baseline task with unmodified stimuli, and then compared to responses with resynthesized stimuli under three conditions: (1) normalized mean-pitch; (2) normalized duration; and (3) normalized linear predictive coefficients (LPCs). The results of these experiments suggest that perceptual speaker discrimination is robust to acoustic changes, though mean-pitch and LPC modifications are more detrimental to a listener's ability to successfully identify same or different speaker pairings. However, this susceptibility was also found to be partially dependent on the specific speaker and utterances.