Vocal cues to speaker affect: Testing two models

We identified certain assumptions implicit in two divergent approaches to studying vocal affect signaling. The ‘‘covariance’’ model assumes that nonverbal cues function independently of verbal content, and that relevant acoustic parameters covary with the strength of the affect conveyed. The ‘‘configuration’’ model assumes that both verbal and nonverbal cues exhibit categorical linguistic structure, and that different affective messages are conveyed by different configurations of category variables. We tested these assumptions in a series of two judgment experiments in which subjects rated recorded utterances, written transcripts, and three different acoustically masked versions of the utterances. Comparison of the different conditions showed that voice quality and F0 level can convey affective information independently of the verbal context. However, judgments of the unaltered recordings also showed that intonational categories (contour types) conveyed affective information only in interaction with grammatical features of the text. It appears necessary to distinguish between linguistic features of intonation and other (paralinguistic) nonverbal cues and to design research methods appropriate to the type of cues under study.