Experimental paradigm influence subject’s perception of attitudes

Abstract

Japanese utterances spoken with different attitudes (admiration, suspicion, and disappointment) were independently manipulated for pitch-contour and voice quality using STRAIGHT {Kawahara}. Close copy stylization of the prototypical pitch contour for the three attitudes was imposed on the naturally spoken utterances, producing stimuli with all combinations of voice quality types and pitch-contour shapes. The utterances were submitted to two separate experiments, wherein subjects were asked to judge the attitude of the morphed utterances. The first, a forced choice experiment, asked subjects to choose if the utterances were admiration, suspicion, or disappointment, and the second, a free choice experiment, where subjects could freely choose the attitude they perceived. The results from the forced choice test indicated that subjects used pitch contour cues to choose speaker attitude. However, the results from the free choice paradigm indicated that subjects used both voice quality and intonation cues, and were able to perceive more affect types than the original three. Whereas the forced choice paradigm suggested that intonation was the primary cue for listeners to determine speaker attitudes, the free choice paradigm suggested an independence of voice quality and intonation in determining speaker attitudes, which resulted in a larger number of perceived attitudes by listeners.