Psychoacoustic studies on the processing of vocal interjections: how to disentangle lexical and prosodic information?

Both intonation (affective prosody) and lexical meaning of verbal utterances participate in the vocal expression of a speaker's emotional state, an important aspect of human communication. However, it is still a matter of debate how the information of these two 'channels' is integrated during speech perception. In order to further analyze the impact of affective prosody on lexical access, so-called interjections, i.e., short verbal emotional utterances, were investigated. The results of a series of psychoacoustic studies indicate the processing of emotional interjections to be mediated by a divided cognitive mechanism encompassing both lexical access and the encoding of prosodic data. Emotional interjections could be separated into elements with high- or low-lexical content. As concerns the former items, both prosodic and propositional cues have a significant influence upon recognition rates, whereas the processing of the low-lexical cognates rather solely depends upon prosodic information. Incongruencies between lexical and prosodic data structures compromise stimulus identification. Thus, the analysis of utterances characterized by a dissociation of the prosodic and lexical dimension revealed prosody to exert a stronger impact upon listeners' judgments than lexicality. Taken together, these findings indicate that both propositional and prosodic speech components closely interact during speech perception.