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Humor is a social phenomenon. People laugh much more when they are around other people, and it's no accident that laughter is so contagious. If you watch a comedy movie with friends, you are much more likely to laugh out loud from even the silliest joke, but most of those who watch a comedy alone hardly giggle. TV makers understood this early on when they added laugh tracks to their shows, thus making you feel that you are not watching it alone and increasing the perceived funniness of the show (for all you trivia buffs, The Hank McCune Show was the first show to include laugh tracks in 1950).
Humor and laughter induce changes in the behaviors of others, putting them at ease and breaking interpersonal barriers. They can also affect how you are perceived and can help you attract mates. If someone shares a laugh with you, it means you both probably share other interests and values as well, and is a good sign for lasting friendships or romantic relationships. Are these behaviors unique to humans? A new study tries to answer this question.
Chimpanzees are our closest relatives and as such, can shed light on the origins of humor and laughter. Studies done by primatologists have already found that many of the great apes smile and laugh. Apes usually exhibit two different expressions that appear in two distinct situations. One is the silent bared teeth display, which is equivalent to the human smile, and appears as an appeasing function or when apes tickle each other. The other one is called the relaxed open mouth and is equated to human laughter. This usually appears during play. But can these displays also elicit smiles and laughter in other apes?
In the current study, 60 chimpanzees in Zambia were observed during natural social play. The researchers documented how often an individual laughed, following the laugher of his or her playmate. They also analyzed the acoustic features of the different laughs.
The results showed that indeed, chimpanzees do laugh following another chimp's laugher. Interestingly, this type of induced laughter is different from the original, spontaneous laughter which they responded to. As the authors of the article indicate, this type of positive expression of emotion represents emotional intelligence and empathy in humans, and usually promotes cooperation and social communication. In chimps, it might represent the same functions. Moreover, chimps who replicated the laughter of others played for a longer time, hence helping them to gain more social benefits from it.
The laugh bouts of the chimps responding to laughter were significantly shorter, just like in humans, and might promote social interactions and social cohesion. Interestingly, orphans who had just joined a new group tended to laugh more during play in response to other chimps' laughter, even though they had fewer playing opportunities. This might indicate their willingness to belong as part of the group.
What does all this say about human laughter? For one, it seems that laughter is deeply rooted in our hominid history. The very basic act of sharing a good laugh played an important role in our social evolution. We already know that apes and monkeys imitate noises and facial expressions of other apes and monkeys, but the fact that they make a distinct laugh sound suggests something beyond just imitation. This laughter serves as a social communication and social affiliation mechanism. Humans, of course, engage in far more social activities than other apes, and laughter seems to play a very important role in many of those activities and interactions with others. How you react to humor says something about who you are, what you think about others, and your outlook on life. If nothing else, laughter makes you feel good.
