Laughter lies

When was last time you faked a laugh? Come on, you know you have done it. Perhaps it was when Great Uncle Ken told you for the 15th time the hilarious tale of when he had mistaken the blue tongue lizard for a Garden trowel. Maybe it was at the last staff meeting when the CEO made a fairly pungent joke about cheese and annual profits? It might just have been when everyone else collapsed into hilarity at a casual witty remark your friend made, which made no sense to you, but you thought it best to seem in with the joke? Fake laughter is part of everyone’s social kit-bag but it may disturb you to know that, according to new research, people know when you’re faking it … mostly.

The study involved gaining recordings of people engaged in genuine laughter and then recording other people when they fake laughed on command. These recordings were then played to a group of subjects. When asked to determine whether the laughs were real or fake, the subjects were largely accurate although they were fooled by about 37 per cent of the fake laughs.

In a second experiment, the researchers sped up the recordings and they found that this significantly increased the likelihood that both kinds of laughter were judged as genuine.

Then, in a third experiment, the laughs were slowed down and the subjects were asked to identify which laughs were made by humans. It turned out that when the laughs were slowed the subjects could not tell whether the genuine laughs were human or not but they could tell that the fake laughs were made by humans.

The researchers believe that genuine laughs are made by a vocalisation system that humans share with all primates. Chimps, gorillas and orang-utans all laugh and the same vocal system is used by humans to genuinely laugh, which is why when slowed down no difference was detectable from other primates. They believe that fake laughs, though, are made using a speech system that is unique to humans.

Analysis revealed that laughs contain the vowel sounds such as “ha” and breathy bits of air between those vowel sounds. Combine the “ha” and the breath and you get a “call”. In genuine laughter the proportion of breathy parts of the call was significantly greater than in the fake laughter. It seems that the emotional vocal system has greater control of the windpipe than the conscious use of the speech system. In essence, more breathy laughter sounds more genuine.

Of course, fake laughter serves a purpose. Even when someone knows you are fake laughing it is a kind of social courtesy that allows both parties to retain their dignity. The alternative might be to spit in their eye and say, “Not that tired old line again.”

Still, if you do want to appear genuinely amused, you’d best sharpen your faux-laughter skills by getting a little more breathless or the joke may be on you.