behavioural economics

there is a curious result in behavioural economics, which shows that paying people to do what they like to do, sometimes provides a disincentive for them to do it, and people correspondingly lower their effort to do the task. The example I recently came across, from the 7 Rules of Behavioural Economics, or some such, was that if you pay people to have their friends for dinner, they entertain less. But, enough about the decline of intradepartmental socialization... The reason I thought of this, is that yesterday we congratulated a colleague on a nice result, and another colleague asked some…