Clapping is contagious and the length of applause an audience gives depends on how other members of the crowd behave rather than the quality of a performance, scientists have found.
Swedish researchers found that it takes a few people to start clapping for applause to spread through a group, and then just one or two individuals to stop for it to die out.
"You can get quite different lengths of applause - even if you have the same quality of performance. This is purely coming from the dynamics of the people in the crowd," lead author Dr Richard Mann, from the University of Uppsala, said.
Researchers studied video footage of groups of undergraduates as they watched a presentation, BBC News reported.
They found that it took just one or two people to put their hands together for a ripple of applause to spread through the crowd.
These claps sparked a chain reaction, where, spurred on by the noise, other audience members joined in.
"The pressure comes from the volume of clapping in the room rather than what your neighbour sitting next to you is doing," said Mann.
However, the performance that had been witnessed – no matter how brilliant - had little effect on the duration of the noisy acclaim.
"In one case an audience might clap on average 10 times per person. Another time they might clap three times as long," Mann told the BBC.
"And all that comes from is that you have this social pressure to start (clapping), but once you've started there's an equally strong social pressure not to stop, until someone initiates that stopping," he said.
The scientists believe that clapping is a form of "social contagion", which reveals how ideas and actions gain and lose momentum.
The study was published in the Journal of the Royal Society Interface.