Laugh and the whole world laughs with you: why the brain just can't help itself

13 December 2006

Cricket commentator Jonathan Agnew's description of Ian Botham's freak dismissal, falling over his own stumps - "He couldn't quite get his leg over" - was all it took to send himself and the late Brian Johnston into paroxysms of laughter. Laughter is truly contagious, and now, scientists studying how our brain responds to emotive sounds believe they understand why.

Researchers at University College London (UCL) and Imperial College London have shown that positive sounds such as laughter or a triumphant "woo hoo!" trigger a response in the listener's brain. This response occurs in the area of the brain that is activated when we smile, as though preparing our facial muscles to laugh. The research, funded by the Wellcome Trust, Action Medical Research and the Barnwood House Trust, is published today in the Journal of Neuroscience.

"It seems that it's absolutely true that 'laugh and the whole world laughs with you'," says Dr Sophie Scott, a Wellcome Trust Senior Research Fellow at the Institute of Cognitive Neuroscience, UCL. "We've known for some time now 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 - at least at the level of the brain."

The research team played a series sounds to volunteers while measuring their brain's response using an fMRI scanner. Some of the sounds were positive, such as laughter or triumph, while others were unpleasant, such as screaming or retching. All of the sounds triggered a response in the volunteer's brain in the premotor cortical region, which prepares the muscles in the face to respond accordingly, though the response was greater for positive sounds, suggesting that these were more contagious than negative sounds. The 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, whether watching a comedy programme with family or a football game with friends," 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. It could play an important role in building strong bonds between individuals in a group."

So, if you want Christmas with the extended family to go swimmingly, maybe you should switch off 'EastEnders' and dig out your 'Only Fools and Horses' DVDs.

Contact

Craig Brierley
Media Officer
Wellcome Trust
T +44 (0)20 7611 7329
E c.brierley@wellcome.ac.uk

Notes for editors

'Positive emotions preferentially engage an auditory-motor mirror system' by Jane E Warren, Disa A Sauter, Frank Eisner, Jade Wiland, M Alexander Dresner, Richard JS Wise, Stuart Rosen, Sophie K Scott; Journal of Neuroscience, 13 December 2006.

1. Download the clip of Jonathan Agnew and Brian Johnston (BBC website).

2. The Wellcome Trust is the largest independent medical research charity in the UK and the second largest in the world. It funds innovative biomedical research, in the UK and internationally, spending around £500 million each year to support the brightest scientists with the best ideas. The Wellcome Trust is committed to public debate about biomedical research and its impact on health and wellbeing.

3. University College London
Founded in 1826, UCL was the first English university established after Oxford and Cambridge, the first to admit students regardless of race, class, religion or gender, and the first to provide systematic teaching of law, architecture and medicine. In the Government's most recent Research Assessment Exercise, 59 UCL departments achieved top ratings of 5* and 5, indicating research quality of international excellence.

UCL is the fourth-ranked UK university in the 2006 league table of the top 500 world universities produced by the Shanghai Jiao Tong University. UCL alumni include Mahatma Gandhi (laws 1889, Indian political and spiritual leader); Jonathan Dimbleby (philosophy 1969, writer and television presenter); Junichiro Koizumi (economics 1969, Prime Minister of Japan); Lord Woolf (laws 1954 - Lord Chief Justice of England and Wales), Alexander Graham Bell (phonetics 1860s - inventor of the telephone), and members of the band Coldplay.

4. Imperial College London is consistently rated in the top three UK university institutions. It is a world-leading science-based university whose reputation for excellence in teaching and research attracts students (11 000) and staff (6000) of the highest international quality. Innovative research at Imperial explores the interface between science, medicine, engineering and management, and delivers practical solutions that enhance the quality of life and the environment, underpinned by a dynamic enterprise culture.

5. Action Medical Research is a national charity dedicated to building a healthier future for everyone. The charity is funding research into many serious diseases and conditions, including premature birth, cerebral palsy, epilepsy, osteoporosis, sickle cell disease, Parkinson's disease and stroke.

As part of wider research into language and brain function, Action Medical Research funded a recent study at Imperial College, London into the communication problems affecting stroke patients. This work has helped improve understanding of language recovery after stroke.

6. Barnwood House Trust is a registered charity that has been assisting disabled people in Gloucestershire for over 200 years.The Trust grants some £750 000 pa to improve the lives of disabled people in Gloucestershire as well as delivering subsidised housing, day and other innovative services for disabled people.