Next time you're at the theatre and you hear deafening applause, be suspicious. It might be a sign that the show's excellent. But it might be because the claquers have been well paid.
Claquers are audience members paid to clap at appropriate moments. The practice has petered out in the UK but still occurs at high-profile venues, such as the Bolshoi.
Once common-place, audience stooges were so widespread in 19th century French theatre that specialist roles developed.
There were claquers, but also rieurs, (who focused on laughing), pleureurs (who could cry on demand) and even bisseurs (who bellowed "encore").
Theatre impresarios paid handsomely for these services as they realised that a great performance didn't just come from the stage.
"The audience does not trust itself, it trusts someone else," the ballet critic Vadim Gayevsky told the New York Times. "If they hear someone applauding very aggressively and intensively, they think that something extraordinary is going on."
The academic evidence for social proof
This is an example of what psychologists call social proof - the idea that people are consciously, or subconsciously, influenced by what others around them are doing.
A study by two University of Houston psychologists, Yong Zhang and George Zinkan, explored the effect of group size on humorous ads. They recruited 216 people to watch soft drink commercials, either on their own or in groups.
Their key finding was that ads watched in groups were rated as 20% funnier than those watched alone.
What can brands learn from the social nature of humour?
The main point is that the wit of an ad is not just a creative issue but also one of media placement. The perception of humour can be boosted through channel selection or implementational tactics.
One such tactic is to run copy in programs or genres which tend to be watched in groups. For example, films, documentaries and news are around twice as likely as TV as a whole to be watched in groups according to Infosys data.
From a channel planning perspective, running humorous copy in cinema is another opportunity as it means the ad will be consumed in much larger groups.
Millward Brown undertook research that quantified the impact. In their experiment an unnamed brand ran the same piece of copy in two regions. One region just aired TV whilst the other just had cinema.
Those who saw the cinema ad enjoyed it considerably more than the TV ad - with 61 per cent saying they "enjoyed the humour" compared to 52 per cent of the TV viewers.
Applying these approaches won't make a mediocre ad side-splitting but it might just give it an edge over copy bought in a more generic manner.