Laughter as an approach to vocal evolution: The bipedal theory

Abstract

Laughter is a simple, stereotyped, innate, human play vocalization that is ideal for the study of vocal evolution. The basic approach of describing the act of laughter and when we do it has revealed a variety of phenomena of social, linguistic, and neurological significance. Findings include the acoustic structure of laughter, the minimal voluntary control of laughter, the punctuation effect (which describes the placement of laughter in conversation and indicates the dominance of speech over laughter), and the role of laughter in human matching and mating. Especially notable is the use of laughter to discover why humans can speak and other apes cannot. Quadrupeds, including our primate ancestors, have a 1:1 relation between breathing and stride because their thorax must absorb forelimb impacts during running. The direct link between breathing and locomotion limits vocalizations to short, simple utterances, such as the characteristic panting chimpanzee laugh (one sound per inward or outward breath). The evolution of bipedal locomotion freed the respiration system of its support function during running, permitting greater breath control and the selection for humantype laughter (a parsed exhalation), and subsequently the virtuosic, sustained, expiratory vocalization of speech. This is the basis of the bipedal theory of speech evolution.

Prescribing laughter to increase well-being in healthy adults: An exploratory mixed methods feasibility study of the Laughie

“…Increased understanding of the beneficial applications of solo laughter can widen acceptability; to encourage this it would be helpful to de-marginalize solo laughter within gelotology [13]. Although solo laughter is less frequent than social laughter [10], the Laughie demonstrates that it can be a smart and powerful addition to social laughter, not an inferior inconsequential form of it. 'Natural is best' reflects feedback that fake-sounding Laughies were neither effective nor enjoyable.…”

“…While laughing for no reason is sometimes suggested in group interventions [6], as Provine [10] notes social laughter needs no reason as it is the reason. Meaning is central to well-being [36], and participants related their solo laughter to health, happiness, in increasing well-being to 'safe' levels in six participants with baseline well-being below 50%.…”

“…Gelotologists tend to view laughter as a social emotion [10,11] or more specifically, as a reaction to humour [12]. Nevertheless, Fry [3] saw laughter as affecting the 'whole physical being' (p. 114), and Weeks [13] considers solitary laughter 'a significant, complex behaviour' (p. 76); both views inspired the Laughie conceptualisation as a holistic solo laughter tool.…”

“…Laughie duration was inspired by the finding that one minute of self-induced laughter significantly increased positive affect in groups of adults unprompted by humorous stimuli [20]. While the contagious properties of laughter are well known [10], to the best of our knowledge the Laughie explores the potential self-contagious effects of listening to one's own pre-recorded laughter for the first time. Laughie laughter is joyful, happy and cheerful.…”

Empirical approaches to the study of language evolution

“…Despite its Darwinian origins, this model has a checkered history, apparently having been forgotten and then independently rediscovered multiple times (Brown, 2000;Livingstone, 1973;Richman, 1993). In many ways, Robin Dunbar's Bvocal grooming^hypothesis is consistent with the musical protolanguage hypothesis (Dunbar, 1996(Dunbar, , 2016, although it extends beyond song to include more primitive vocalizations such as laughter (see also Dunbar, 2016;Locke, 2016;Provine, 2016). Although Darwin was quite vague about the later stage of semantics (and said nothing about syntax), his ideas were fleshed out by the linguist Otto Jespersen (Jespersen, 1922), who suggested plausible roots for both semantics and syntax (via analysis of previously holistic utterances; cf.…”