An acoustic analysis of laughter produced by congenitally deaf and normally hearing college students

Abstract

Relatively few empirical data are available concerning the role of auditory experience in nonverbal human vocal behavior, such as laughter production. This study compared the acoustic properties of laughter in 19 congenitally, bilaterally, and profoundly deaf college students and in 23 normally hearing control participants. Analyses focused on degree of voicing, mouth position, air-flow direction, temporal features, relative amplitude, fundamental frequency, and formant frequencies. Results showed that laughter produced by the deaf participants was fundamentally similar to that produced by the normally hearing individuals, which in turn was consistent with previously reported findings. Finding comparable acoustic properties in the sounds produced by deaf and hearing vocalizers confirms the presumption that laughter is importantly grounded in human biology, and that auditory experience with this vocalization is not necessary for it to emerge in species-typical form. Some differences were found between the laughter of deaf and hearing groups; the most important being that the deaf participants produced lower-amplitude and longer-duration laughs. These discrepancies are likely due to a combination of the physiological and social factors that routinely affect profoundly deaf individuals, including low overall rates of vocal fold use and pressure from the hearing world to suppress spontaneous vocalizations.

The Importance of Not Being Earnest – The Feeling behind Laughter and Humor

“…Such variations may include, for example, excessive glottal onsets of laughter pulses, ingressive laughter due to restrictions of breath control, and excessive breathiness and voiceless laughs. We do know that laughter in deaf persons is similar to normal laughter but may vary with lower frequency and longer duration [Makagon et al, 2008]. We know less about laughter in other populations with special needs.…”

The animal nature of spontaneous human laughter

“…Laughter is a fundamental communicative signal in humans-it is universally produced and recognizable, ubiquitous across all contexts of social interaction, and reliably developing as early as four months (Sroufe & Wunsch, 1972) with no auditory input required (Eibl-Eibesfeldt, 1970;Makagon, Funayama, & Owren, 2008). Human laughter is likely homologous to play vocalizations associated with the open mouth display in a number of primate species (van Hooff, 1972;Provine, 2000;Davila-Ross, Owren, & Zimmermann, 2009;Vettin & Todt, 2005), and analogous to related vocal signals in other social species, such as rats (Panksepp & Burgdorf, 2003) and dogs (Simonet, 2004).…”

The MAHNOB Laughter database

“…The range reported in the literature [56,[15][16][17]66,7,63] for male and female mean pitch of laughter is 126-424 Hz and 266-502 Hz, respectively. The male mean pitch, 400 Hz, falls in this range but the female pitch, 535 Hz, is slightly higher than what has been previously reported.…”

“…This is a common way of eliciting laughter in psychological studies [16,17,56,7]. Two of the clips were used to elicit laughter in a previous psychological study [16], whereas the other clips were found on the Internet.…”

“…For example, babies have the ability to laugh before they can speak [2], children born both deaf and blind still have the ability to laugh [6], and the acoustic features of laughter produced by congenitally deaf and normally hearing students are similar [7]. Considering its prevalence and universality as a social signal, it is surprising that our knowledge about laughter is still incomplete and little empirical information is available [8].…”