Superior Communication of Positive Emotions Through Nonverbal Vocalisations Compared to Speech Prosody

The human voice communicates emotion through two different types of vocalisations: nonverbal vocalisations (brief non-linguistic sounds like laughs) and speech prosody (tone of voice). Research examining recognisability of emotions from the voice has mostly focused on either nonverbal vocalisations or speech prosody, and included few categories of positive emotions. In two preregistered experiments, we compare human listeners’ (total n = 400) recognition performance for 22 positive emotions from nonverbal vocalisations (n = 880) to that from speech prosody (n = 880). The results show that listeners were more accurate in recognising most positive emotions from nonverbal vocalisations compared to prosodic expressions. Furthermore, acoustic classification experiments with machine learning models demonstrated that positive emotions are expressed with more distinctive acoustic patterns for nonverbal vocalisations as compared to speech prosody. Overall, the results suggest that vocal expressions of positive emotions are communicated more successfully when expressed as nonverbal vocalisations compared to speech prosody.