Why do people cough during concerts?
29 January 2013 Last updated at 10:06 GMT
Many concert-goers are often frustrated by the sound of people coughing during classical music performances.
These coughers have now become the subject of an academic paper concerning "the economics of concert etiquette", which analyses a stark fact: people appear to cough more in concerts than in they do in normal life.
The German economist Andreas Wagener told the Today programme: "The statistics indicate people cough during concerts twice as much as they do in normal life."
Concert pianist Susan Tomes said: "I certainly do notice it, but I think it has something to do with the fact that people have gotten so used to hearing music amplified.
"Many types of music are so loud, but classical music is not, and when you go to a classical concert, you forget how quiet acoustic instruments are."
First broadcast on BBC Radio 4's Today Programme on Monday 28 January 2012.