In The weekend science ticket, Mathilde Fontez, editor-in-chief of the scientific magazine Epsiloon tells us today about the laughter of babies, and about an important discovery the sounds they emit while laughing.
franceinfo: Babies must learn to laugh. Isn’t it innate with them?
Mathilde Fontez: No. So they obviously utter cries that resemble laughter from the first weeks, we all – or almost – had the opportunity to observe it. But Dutch researchers at the University of Leiden have just determined that these sounds do not constitute real laughter. It has nothing to do with it, because they haven’t learned to breathe out laughing yet, and that’s the secret.
An inspired laugh is not a real laugh?
No. In fact, we already knew that. It was the primatologists who had shown it, by observing monkeys therefore: they have a form of laughter different from that of humans. Precisely because this laughter is emitted both when the monkeys breathe out and when they inhale. While our own laughter, human laughter, it produces a so-called “egressive” sound: only on the exhale. This is what gives “Ha! Ha!” good sound.
This is also what makes our laughter communicative. It is these exhalations that make us want to laugh, when we see a man laughing in front of you. Whereas this contagion of laughter does not work at all between us and the monkey.
And babies don’t know how to make that human laugh?
That’s what this new study shows, yes. The researchers played hundreds of volunteers to listen to sound clips of laughter from babies aged 3 months to 1 and a half, and they observed that little by little, these sounds shifted from animal laughter to exhaled laughter.
So they showed that babies laugh like monkeys at first. And as time goes by, they learn to laugh like humans. Either because their vocal channel is developing or because they manage to imitate adults. Probably a bit of both. Babies must understand quickly enough that by giving pleasant laughs, they can positively influence others …