Demystifying science | The contagion of laughter

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The mechanism involved is poorly understood, but the contagion of laughter probably serves to forge social bonds between members of the same group.

“Humans are the only animal species that have contagious laughter,” explains Sophie Scott, a psychologist at University College London (UCL), in London, who has published several studies on the subject. “It is a powerful means of emotional communication, which probably explains the establishment of communities. »

The area of ​​the brain that is stimulated when we hear laughter and, when stimulated, elicits laughter, is very social. “It’s the supplementary motor area, at the top of the skull,” says M.^me Scott. It plays an important role in language, but not in the choice of words, rather in the use of words in a sentence, depending on the social context. It’s an area of ​​the brain that’s very involved when we’re having a conversation with other people, less so when we’re talking on our own. It intervenes when we ask ourselves “what does this person want to know from me?” “.

Contagious laughter probably activates the same social mechanisms as religion or group exercise, according to Robin Dunbar, a psychologist at the University of Oxford and an evolutionary expert who has also studied contagious laughter. “If people laugh at our table at the pub, we laugh, but if people at another table laugh, we get irritated at the disturbance,” Mr. Dunbar says. If we watch a comedian’s video alone, we don’t laugh, but in a group, we laugh. It’s an eminently social laugh. »

Laughter is an almost universal component of the bond between parent and child, through tickling. “It’s one of the most common interactions with babies, we tickle them, they laugh, we laugh,” says M^me Scott. It is impossible to tickle yourself. »

Other animals have social relationships based on shared behaviors, like yawning or scratching, according to M^me Scott. “These are often behaviors that stimulate the expression of endorphins,” says Dunbar. Endorphins are painkillers secreted by the brain. They are sometimes called “happiness molecules”.

Immune system

What are the priority research questions in the field of contagious laughter?

“Fortunately, it’s a field of study that is very ethical,” continues M.^me Scott. Often, study participants cannot be subjected to stimuli, but in the case of laughter, this is not a problem. »

Robin Dunbar believes that we should determine the mechanisms at work in contagious laughter in different situations, when we watch a comedy film together or when we have an inexplicable fit of laughter with another person, for example.

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