Sound of clapping is infectious
Social contagion If you wish to avoid the social faux pas of clapping at the wrong time, listen carefully to the volume of noise around you.
That's the conclusion of a study about the social dynamics of applause led by mathematician Dr Richard Mann from Uppsala University in Sweden.
"Our paper suggests this social information is mediated by the sound of clapping rather than watching people clap," says Mann.
The study, which is reported in Journal of The Royal Society Interface , could help scientists understand how information spreads on social media and other types of group situations such as riots.
"This is a really simple scenario where we can look at human behaviour and observe exactly what individuals did in a very controlled setting," says Mann.
Mann's colleagues filmed six groups each containing between 13 and 20 undergraduate students while they watched two science presentations. Then, frame-by-frame, the researchers analysed when each individual in the group started and stopped clapping.
Mann then used mathematical models to map how information spreads and how humans collectively solve a problem.
The researchers found that the applause followed a pattern typically seen in the spread of diseases.
"You start with a slow growth of clapping in the group, you then get a period where the clapping grows very quickly, and eventually it saturates at a point where everybody is clapping," says Mann.
The researchers then went deeper into the data and looked at what controlled the probability that each individual would start clapping.
"We tested a number of hypotheses and found eventually that the thing that most well predicted what an individual would do is the proportion of the number of people in the room who are already clapping," says Mann.
Starting and stopping
Everyone in the groups started clapping within two to three seconds of each other after the presentation had ended.
However, different groups responded differently to the same presentations, with some groups clapping for twice as long as others.
"Someone has to initiate the stopping process and that can take a very different length of time.
"The audience might clap for say 10 claps on average -- up to 30 or 40 claps per average -- despite there being no intrinsic difference in the talk quality," says Mann.
But when the first person stops, everyone stops within a very short period of time.
"Everyone's waiting for someone to be the first to stop, but once someone has stopped there's very little intrinsic individual force left. You're just stopping because everyone else is stopping."
Interestingly, the same person often initiates the start and stopping of clapping, but Mann says it is unclear whether or not that individual drives the group's decision making.
"They tend to be the person that claps perhaps because they're more enthusiastic rather than because everyone else is waiting for them."
Mann says the study method could be applied to other social contexts, such as analysing social media and crowd behaviour.
"The techniques we've developed here for testing those different kinds of effects could be used to see if people start using a Twitter hashtag more frequently once either their Twitter friends or the Twittersphere in general has started using it.
"Particularly in contexts related to anti-government protests," he says.