One of the most peculiar behaviors innate to humans is laughter. Our ability to laugh is mystifying to behavioral biologists. Darwin noticed that laughter occurs in a variety of emotional states; from anger to joy, nervousness to shame, we use it to both hide and accentuate emotion (Adams & Kirkevold, 1978). It is difficult to imagine why laughing increases behavioral fitness or increases reproductive success. Darwinian evolution postulates that behavior evolves according to their ability to increase fitness. Why, then, is laughter an inborn behavior as opposed to a useful behavior that must be learned, such as hunting? Certainly it yields no obvious practical reason; in fact, being loud and attention-calling, it seems more of a hindrance from predators. The answer is in no way simple, and would have to address an unwieldy heterogeneity of elements, such as ethology, evolutionary biology, and sociology. However, it is becoming more and more clear that laughter, though perplexing, is important.
Classically, ethnological studies have unequivocally thrust laughter in the group of advanced signaling within the complex of socialization, particularly with regards to anthropoid primates. The closest observed behavior similar to human laughter is the ritualized “panting” that chimpanzees perform while playing; when running and chasing each other around, they noisily punctuate their breaths into distinct noise, though they are unable to module their breaths into the discrete tones that characterize human laughter (Ross et al., 2009). However, during the course of evolution, new social behaviors pushed the changes between humans and other primates further down the evolutionary line. Many of these changes were concentrated around the brain, which, when coupled with an increase to the number of group size, lead to the development of an articulate communicative language.
As laughter preceded language evolutionarily, is continues to be used to
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