Why laughter is contagious

Here's the science bit

Scientists believe they’ve worked out why laughter is so contagious.

Researchers at University College London and Imperial College London have shown that just hearing a laugh triggers a response in the part of the brain that’s also activated when we smile. It is, they say, as if hearing laughter prepares our facial muscles to laugh.

Neuroscientist Sophie Scott, pictured, who led the research, said: ‘It seems that it's absolutely true that “laugh and the whole world laughs with you”

‘We've known for some time that when we are talking to someone, we often mirror their behaviour, copying the words they use and mimicking their gestures. Now we've shown that the same appears to apply to laughter, too.’

The research team played a series sounds to volunteers while measuring their brain's response. Some sounds were positive, such as laughter or a triumphant ‘woo hoo’, while others were unpleasant, such as screaming or retching.

All the sounds triggered a response in the volunteer's brain in the premotor cortical region, which prepares muscles in the face to respond accordingly.

But the response was greater for positive sounds, suggesting that these were more contagious than negative sounds. Researchers believe this explains why we respond to laughter or cheering with an involuntary smile.

‘We usually encounter positive emotions, such as laughter or cheering, in group situations, such as watching a comedy programme with family,’ says Dr Scott. ‘This response in the brain, automatically priming us to smile or laugh, provides a way of mirroring the behaviour of others, something that helps us interact socially.

‘With laughter, we don't just have an emotional experience. What you tend to do is see somebody laughing and you actually want to join in.’

The research, part-funded by the Wellcome Trust, has been published in the Journal of Neuroscience.

Published: 28 Dec 2006

Live comedy picks

We see you are using AdBlocker software. Chortle relies on advertisers to fund this website so it’s free for you, so we would ask that you disable it for this site. Our ads are non-intrusive and relevant. Help keep Chortle viable.