The muffled giggle, the high pitch twitter, the polished chuckle, the wheezing chortle, and the deep belly laugh can all be taken differently depending on who is uttering the sound. Real involuntary laughter is often contagious in groups, one person catches on to a joke and others join in with rounds of laughter that rise and fall. But faked laughter is more common in everyday life. It typically serves a type of social interaction and can be used to smooth over differences, appease a person perceived as more important, to draw attention to oneself or increase group cohesion by aiming guffaws of scoffs at an outsider.

A common use of the manufactured laughter, which tends to be slower and more nasal in tone, is to bond with other people. However, faked laughter is only appealing if we actually like the person doing it. I heard a guy comment once that a particular group of women were not attractive enough to be giggling so much. He understood their artificial laughter as a kind of flirtation. He was uncomfortable with their laughter because he did not find them appealing.

According to studies conducted by UCLA associate professor Greg Bryant, most people can only distinguish faked laughter about two/thirds of the time. Detection is based on the “breathiness” of the laugh, which is composed of the vocalized sound. Part of this is the “ha, ha, ha” sound and part is rapid breathing. The slower the laugh is the more we hear the vocalization and the more controlled the breaths seem. When both of these occur people assure that the mirth is fake.

And there is a third kind of laughter – the insidious, haunting kind of evil laughter. What makes it different from the other two? It hints of insincerity because the breathing is clearly controlled, unlike the gasping of real laughter This laugh it is often marked by pitch that trails downward. However, the situation does affect our opinion of legitimacy of the person laughing. A genuine deep belly laugh at at a revolting or grotesque scene, still seems very twisted.

Greg Bryant’s studies are based on idea that many animals use laughter to indicate playfulness similar to a real human laugh. Most people are familiar with the hysterical sounds made by chimpanzees. But what do these chimps find so outrageously funny? Nothing. The chimp’s laughter eases social situations. Did you realize that dogs, also have a way of chuckling? You may not be able to perceive it because it is much more like wheezing than human laughter. However you do not have to worry that your dog is poking fun of you. Dogs use chuckling to appease people, just like other people do.

http://newsroom.ucla.edu/releases/ucla-s-laughter-guy-dissects-features-of-counterfeit-chortling