The acoustic features of human laughter

Remarkably little is known about the acoustic features of laughter. Here, a coustic outcomes are reported for 1024 naturally produced laugh bouts recor ded from 97 young adults as they watched funny video clips. Analyses focuse d on temporal features. production modes, source- and filter-related effect s, and indexical cues to laugher sex and individual identity. Although a nu mber of researchers have previously emphasized stereotypy in laughter, its acoustics were found now to be variable and complex. Among the variety of f indings reported, evident diversity in production modes, remarkable variabi lity in fundamental frequency characteristics, and consistent lack of artic ulation effects in supralaryngeal filtering are of particular interest. In addition, formant-related filtering effects were found to be disproportiona tely important as acoustic correlates of laugher sex and individual identit y. These outcomes are examined in light of existing data concerning laugh a coustics, as well as a number of hypotheses and conjectures previously adva nced about this species-typical vocal signal. (C) 2001 Acoustical Society o f America.