Listener Performance in a Speaker-Verification Task with Deliberate Impostors

Abstract

In a previous experiment [Rosenberg, J. Acoust. Soc. Amer. 50, 106(A) (1971)] listener performance was evaluated in a speaker verification task in which 32 “casual” impostors were pitted against eight “true” speakers. A “casual” impostor is one who makes no attempt to mimic the “true” speaker but simply repeats the same test utterance in his own natural voice. In the present experiment four professional mimics were engaged to deliberately imitate each of the eight “true” speakers. After intensive training their recorded utterances were used in an experiment in which 10 listeners participated. Each stimulus presentation was a paired comparison consisting of a challenge and a reference utterance. The reference utterance was one of the “true” speaker utterances while the challenge was, with equal likelihood, a mimic utterance of the reference speaker, a natural utterance of one of the mimics, or another utterance from the reference speaker. The results of the present experiment are compared with the results of the previous experiment cited and the performance of an automatic system for speaker verification [Lummis, J. Acoust. Soc. Amer. 50, 106(A) (1971)].