Speaker identification: Effects of vocal disguise upon listener performance

This research was designed to investigate the effects of vocal disguise upon speaker identification by listening. The experiment consisted of fixed‐sequence pair discriminations. The listeners were asked to decide whether the two sentences were uttered by the same or different speakers and to rate their degree of confidence. The speakers produced two sentence sets utilizing their normal voice and five disguises. One number of each pair in the task was always undisguised; the other member was either disguised or undisguised. Two listener groups were trained for the task: a group of 24 undergraduates and a group of six doctoral students and professors of Speech and Hearing Sciences. Both groups of listeners were able to discriminate speakers with a moderately high degree of accuracy (92% correct) when both members of the stimulus pair were undisguised. The inclusion of disguised speech samples in the stimulus pair significantly interfered with performance (59%–81% correct depending upon the particular disgu...