Vocal Expression of Affective States in Spontaneous Laughter reveals the Bright and the Dark Side of Laughter

Data availability: Data have been made publicly available at Figshare and can be accessed at https://doi.org/10.17633/rd.brunel. 15028296.Copyright © The Author(s) 2022. It has been shown that the acoustical signal of posed laughter can convey afective information to the listener. However, because posed and spontaneous laughter difer in a number of signifcant aspects, it is unclear whether afective communication generalises to spontaneous laughter. To answer this question, we created a stimulus set of 381 spontaneous laughter audio recordings, produced by 51 diferent speakers, resembling diferent types of laughter. In Experiment 1, 159 participants were presented with these audio recordings without any further information about the situational context of the speakers and asked to classify the laughter sounds. Results showed that joyful, tickling, and schadenfreude laughter could be classifed signifcantly above chance level. In Experiment 2, 209 participants were presented with a subset of 121 laughter recordings correctly classifed in Experiment 1 and asked to rate the laughter according to four emotional dimensions, i.e., arousal, dominance, sender’s valence, and receiver-directed valence. Results showed that laughter types difered signifcantly in their ratings on all dimensions. Joyful laughter and tickling laughter both showed a positive sender’s valence and receiver-directed valence, whereby tickling laughter had a particularly high arousal. Schadenfreude had a negative receiver-directed valence and a high dominance, thus providing empirical evidence for the existence of a dark side in spontaneous laughter. The present results suggest that with the evolution of human social communication laughter diversifed from the former play signal of non-human primates to a much more fne-grained signal that can serve a multitude of social functions in order to regulate group structure and hierarchy.German Research Foundation (SZ 267/1-1; DP Szameitat).https://doi.org/10.17633/rd.brunel. 1502829