The ontogeny of human laughter

Abstract

Human adult laughter is characterized by vocal bursts produced predominantly during exhalation, yet apes laugh while exhaling and inhaling. The current study investigated our hypothesis that laughter of human infants changes from laughter similar to that of apes to increasingly resemble that of human adults over early development. We further hypothesized that the more laughter is produced on the exhale, the more positively it is perceived. To test these predictions, novice ( n = 102) and expert (phonetician, n = 15) listeners judged the extent to which human infant laughter ( n = 44) was produced during inhalation or exhalation, and the extent to which they found the laughs pleasant and contagious. Support was found for both hypotheses, which were further confirmed in two pre-registered replication studies. Likely through social learning and the anatomical development of the vocal production system, infants' initial ape-like laughter transforms into laughter similar to that of adult humans over the course of ontogeny.

The Role of Contextual Information in Classifying Spontaneous Social Laughter

“…Laughter is not only a signal of joy, pleasure, or amusement, but also a complex social behavior observed among humans and other mammalian species (Kret et al, 2021;Panksepp & Burgdorf, 2003;Provine, 2000;Winkler & Bryant, 2021). Humans laugh as many as 5 times during every 10 min of conversation (Vettin & Todt, 2004), and systematically underestimate the number of times they laugh during the day (e.g., Mannell & McMahon, 1982;Martin & Kuiper, 1999).…”

A Longitudinal Characterization of Typical Laughter Development in Mother–Child Interaction from 12 to 36 Months: Formal Features and Reciprocal Responsiveness

“…While laughter has received attention from a wide range of researchers-it is present, for instance, in many of Piaget's observations (Piaget, 1945)-systematic studies on laughter development are sparse. There have been studies on laughter phonetics and acoustics in infants (Kret et al, 2021;Sauter et al, 2018) and studies looking at the relationship between child smile and laughter production and several mother characteristics such as personality traits, parenting, and attachment styles (e.g., Bridgett et al, 2013;Malatesta et al, 1989;Washburn et al, 1972). All these studies yield important insights into laughter evolution and the crucial role that laughter has for the development of a baby.…”

Laughter, play faces and mimicry in animals: evolution and social functions

“…More research is, however, needed on this topic. In a recent psychoacoustic study, Kret et al [ 141 ] played back human infant laughter to adult participants, who were asked to determine the airflow direction from the recordings. The researchers found that the infants produced laughter increasingly as an egressive vocalization (i.e.…”

“…The researchers found that the infants produced laughter increasingly as an egressive vocalization (i.e. a vocalization that is produced during the exhalation phase only; see [ 22 , 142 ]) over time and that this acoustic trait was perceived to be more positive by the adult listeners [ 141 ]. Such developmental findings could indicate that human infants already adjust laughter to their acoustic environment via social feedback.…”