Dear Economist...

By Tim Harford

Published: May 11 2007 18:35 | Last updated: May 11 2007 18:35

Dear Economist,

At the end of concerts the performers leave the stage to the sound of applause. I prefer to save my energy, especially when many of my fellow concert-goers are applauding on my behalf.

From a strictly economic viewpoint I believe that my behaviour is rational but why do others not behave as I do? Please do not fob me off with the explanation that the applause is thanks for an excellent performance.

I bought my ticket in the expectation of an excellent performance and the delivery of that is the performers living up to their side of the bargain.

Kind regards,

S.C. Li, via e-mail

Dear S.C. Li,

What can I say? People do not always behave rationally. Perhaps the trendy behavioural economists will strap audiences into brain scanners and produce an explanation; I do not know.

One thing of which we can be sure is that rational audiences do not applaud. The renowned economist Avinash Dixit, perhaps fearing that his students will be all-too-rational after his course of game theory, offers an incentive payment of $40 to the last person to stop clapping at the end of his lecture series.

Research by Jeremy Bulow and Paul Klemperer shows that in such circumstances, the rational strategy is for all but two to stop applauding almost immediately. As long as there are several others clapping, one extra clap is so unlikely to deliver you victory that you should give up before bothering to clap it. Only if just one opponent is clapping should you persist. Recently, however, six of Professor Dixit’s students clapped for over two hours before agreeing to share the prize. Perhaps they did not understand his material after all.