Laughter: A Stereotyped Human Vocalization

Laughter is a common, species‐typical human vocal act and auditory signal that is important in social discourse. In this first quantitative description of laughter, we identified stereotyped features of laugh‐note structure, note duration (x̄ = 75 ms), internote interval (x̄ = 210–218 ms), and a decrescendo that contribute to laughter's characteristic sound. Laugh‐notes and internote intervals have sufficient temporal symmetry and regularity to pass the reversal test; recordings of laughter sound laugh‐like when played in reverse. The stereotypic, species‐typical character of laughter facilitates the analysis of the neurobehavioral mechanisms of laugh detection and generation and the more general problems associated with the production, perception, and evolution of human auditory signals of which speech is a special case.