Prosodic features conveying doubt and trust

Abstract

Research in affective prosody has shown that doubt (specifically, incredulity) is communicated through distinctive features like a slower speech rate, greater variability in fundamental frequency (F0), and a characteristic F0 pattern including an utterance final rise in F0. However, the opposite of doubt, trust (or belief), has not been examined as a prosodically distinct attitude. In response, this study explores the full range of doubt and trust native speakers of American English can express through prosody. In a web-based production experiment, we asked 30 participants to produce 12 utterances in neutral, trusting, and doubting prosody. A multinomial logistic regression analysis revealed that incredulous prosody differed significantly from neutral prosody primarily in its lower initial F0 and longer duration. Trust also differed from neutrality, with a significantly higher utterance initial F0 and less amplitude variability than was observed in neutral utterances. In a perception experiment, 115 participants listened to 36 tokens collected from the production experiment and were asked whether the talker expressed doubt or trust. Participants were generally accurate in their judgement of talker attitude, and acoustic variables of utterance-initial F0 and speech rate significantly predicted participant ratings of the talker's doubt or trust.