Laughter constitutes a multimodal pattern of affective vocalisations, facial expressions, and body movements dating back evolutionarily over 10 million years. This complex and dynamic behaviour occurs in all types of social circumstances and can convey a variety of communicative messages. The meaning and function of laughter are only recently beginning to be understood. An investigation of different kinds of laughter, their distinctiveness, and the social tasks they serve can shed light on the mechanisms underlying the processing of this multifaceted behaviour. This symposium brings together scientists studying laughter in order to discuss novel research findings and stimulate debate about this emotional expression. The first presenter will consider the vocalisation mechanisms underlying the production of spontaneous and conversational laughter. Are there different types of genuine laughter? To what extent do these types convey information regarding a sender’s feelings and motivations? This question will be discussed in the second talk, focusing on specificity versus ambiguity of laughter. From an evolutionary perspective, the expression of laughter can be viewed as an important tool for promoting and signalling social affiliation. The subject of the third presentation is colaughter, which is the simultaneous production of laughter between individuals in groups. The fourth and final speaker will consider further the social functions of laughter and its potential to serve the tasks of rewarding others, maintaining social relationships, and signalling superiority. We will discuss the relevance of these sometimes conflicting approaches and results to human behaviours beyond laughter, such as gossip, empathy, and smiles.
Laughter accompanies a variety of social contexts and internal states. It also takes many acoustic forms. I suggest this diversity occurs because laughter can serve multiple social functions: 1) rewarding the behavior of others; 2) easing of social tension and signaling of affiliation; and 3) enforcing social norms, negotiating status, and correcting undesirable behavior in others by conveying dominance. I propose that people modify physical properties of their laughter in the service of the three social tasks, and that the acoustic modulations follow principles common to human and non-human vocal signaling. Recent work identified acoustic patterns that convey reward, affiliation, and dominance using perceiver judgments of actor-generated laugh samples. Here I present new findings from a naturalistic laughter production study in which pairs of same-gender participants (complete audio recordings, N= 141) freely discussed humorous videos they identified as eliciting rewarding, affiliative, and dominant responses. A total of 4,606 laughter samples were extracted from the conversations. Several acoustic properties differed systematically across the three conversation contexts, some of which converged with the prior perceiver-based study. I discuss the distinct insights perceiver- and producer-based paradigms reveal and contextualize the acoustic profiles of laughter within the broader human and non-human signaling literature.
Human laughter is a universal nonverbal affective vocalization homologous to play vocalizations in the great apes, and other mammalian species. Colaughter is the simultaneous production of laughter in groups and its occurrence is closely linked to social affiliation and cooperative intent between vocalizers. Here I will present evidence for a group signaling theory of colaughter that extends the functions of laughter beyond the immediate interactive context to intergroup communication. Specific acoustic and psychological features of human laughter including alerting components, overall loudness, conspicuousness, and high contagion suggest a group chorusing function. I will present data from three lines of research, including a large-scale cross-cultural study of colaughter perception, a study examining the recognition of affiliation in colaughter and cospeech, and developmental work investigating colaughter perception in preverbal infants. Together, these results provide preliminary evidence for an intergroup signaling function of colaughter and help explain some of laughter’s more puzzling features from an evolutionary perspective.
Laughter is a non verbal expression of emotion which has a range of complex, nuanced uses in human interactions - from social bonding and play to communication and emotion regulation. In this talk I will discuss the neural systems recruited during the perception and production of laughter. Production is hard to investigate but we can distinguish between networks recruited for spontaneous vs voluntary motor control, and I will show how these can be important in the production of laughter. The perception of laughter involves the dorsolateral temporal lobes, sensory-motor cortex and medial prefrontal fields. This perception networks can be differentially modulated: spontaneous and communicative laughter recruit these fields somewhat differently, for example. There are also important individual differences - greater sensory-motor network recruitment is seen in participants who are better at distinguishing spontaneous vs communicative laughter in offline tests. Teenage boys at risk of psychopathy, in contrast, recruit these sensors-motor networks significantly less. I will conclude with some suggestions about other factors that may modulate these neural systems, including age and context.
The central question of this work is whether laughter conveys specific feelings or is ambiguous and used to enhance or accentuate emotions in others. We test this question using a new methodological approach allowing non-intrusive recording of spontaneous laughter in social settings. We used the technique in two studies (N = 101; N = 404), to record laughter in groups talking about pleasurable experiences, and to alter the recorded sequences. Specifically, the original laughs were replaced by other laughs taken from different points in the same conversation. The intensities of the substituted laughs were matched to or different from the original intensities. Participants watched the unaltered and the modified videos and judged the genuineness of each interaction. Interchanging laughter did not decrease the perceived genuineness as long as the laughter intensity remained the same. In other words, the same laughs could be flexibly used across contexts. This finding suggests that laughter does not convey information about the sender’s state but rather enhances emotions induced by the context. Our more recent studies extend these findings to laughs produced in different situations. We recorded participants (N = 61) in contexts engineered to induce amusement, embarrassment, and schadenfreude. Their laughs are used as stimuli in a series of studies exploring the informative value of laughter as a signal. The findings will reveal how much of the meaning of laughter depends on the surrounding context, facial and bodily expressions, and acoustics, thus providing important insights into the flexibility of laughter as a communication tool.