Growing up laughing: Laughables and pragmatic functions between 12 and 36 months

Abstract

Laughter serves a wide variety of functions in adult interaction, some of which are quite sophisticated from a pragmatic perspective. Nevertheless, it is a vocalization that emerges very early in ontogeny. We present a longitudinal semantic and pragmatic study of laughter among four American English mother-child dyads interacting freely at home from 12 to 36 months of age. Our data show differences in child laughter-use compared to mothers and a developmental trajectory in terms of the entities the laughter is related to, of laughter pragmatic functions, and in the amount of shared attention on the object of mothers’ laughter. We observe differences in mother laughter-use by comparison to patterns observed in adult-adult interaction. This suggests that laughter production, conveying meaning in a manner akin to speech, gets modulated in child directed interactions similarly to spoken utterances. Our data show that laughter-use can be informative about the neuro-psychological development of babies very early on: mirroring acquisition of physical world knowledge, development of social cognition, linguistic and pragmatic abilities. Our results constitute the basis for hypotheses about the co-option trajectory of laughter in humans and suggest that laughter production in interaction is a valuable resource for early pragmatic development evaluations.