Greg Bryant: UCLA Department of Communication Studies, Center for Behavior, Evolution and Culture

Laughter is a universal vocal signal ubiquitous in human social interaction and homologous to play vocalizations across several primate species. In this talk I will describe two different lines of research on the production and perception of laughter. One series of experiments examined the perception of spontaneous versus volitional laughter. Specifically, we explored relationships between particular acoustic features of laughs and judgments of how “real” they sounded, as well as a study examining the connection between spontaneous human laughter and nonhuman animal vocalizations. In another series of studies, participants across 24 societies reliably identified affiliative partners from extremely brief, decontextualized clips of recorded conversational co-laughter. Several acoustic dimensions contributed to people’s judgments of affiliation, and these results did not vary substantially across population samples. Overall, laughter is an important social vocalization with deep evolutionary roots, unique acoustic features, and a variety of possible communicative functions, both within and between groups.