Laughter, the best medicine We all like a good laugh. But how many of us know why? Humour, schadenfreude, tickling, nerves – all can trigger a ho-ho-ho or a heh-heh-heh. What does that tell us about laughter? Is laughing a uniquely human state, and why, if we hear someone laughing, do we want to join in? On the coming pages, Kate Douglas and David Robson put on a straight face and look for the answers. Meanwhile on page 36, acoustician Trevor Cox invites you to participate in an online experiment to answer another burning question: can we make a computer laugh convincingly?
What are you laughing at?
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gnoring any aggressive intent in the above question, the answer is obvious: I am laughing because something you said amused me. Right? Wrong. According to a classic study of laughter by Robert Provine of the University of Maryland, Baltimore County, and his colleagues, laughter is an unexpectedly serious business. Observing the human animal in its natural habitat – the shopping mall – they documented 1200 instances of laughter, and found that only 10 to 20 per cent of them were responses to anything remotely resembling a joke. Most laughter was in fact either triggered by a banal comment or used to punctuate everyday speech. Furthermore, says Provine in his book Laughter: A scientific investigation, we are 50 per cent more likely to laugh when speaking than when listening, and 30 times gigglier in a social setting than when alone without a social surrogate such as a television. Provine’s conclusion was that the essential ingredient for laughter is not a joke but another person. Laughter is far more general than just a response to humour: it is a social glue that we use in all sorts of ways to bind ourselves together. As such, it comes in many guises. Our first laughs occur at between 2 and 6 months of age – even in deaf babies. They are triggered by surprise in a safe situation (think peek-a-boo), and don’t
just endear babies to their parents. Since laughter is associated with activity in the brain’s dopamine reward circuitry, it encourages babies to explore the world by making them feel happy and safe. When infants begin to engage in rough-andtumble play, laughter signals that the intentions are not serious, allowing children to test physical and social boundaries without serious jeopardy. The conversational laughter Provine observed essentially acts as a social lubricant. It engages listeners and dispels tension, aggression and competition by putting people at ease. Nervous laughter can make light of a stressful or psychologically difficult situation. And, through its catching nature (see “Why is laughter contagious?”, page 36), laughter can unify the mood and behaviour of a group, promoting coordinated activity for the greater good (The Quarterly Review of Biology, vol 80, p 395). Laughter also has a darker side. “You can influence the behaviour of others through laughter,” says Michael Owren, a psychologist at Georgia State University in Atlanta. He believes that as we master the subtle cues of laughter, so we begin to use it to manipulate those around us. An “in” joke can exclude outsiders from a clique, for example. Laughter can be used to show who is boss and malicious laughter is an effective weapon of intimidation. Kate Douglas
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