Getting cooperation

From the NYC Mom's Blog: [HT: NYT's Motherlode] in reaction to her kids' constant bickering:

The next day I decided to try a new tactic. I told them that whichever one of them bugged me the least all day, didn't tattle and didn't bother the other one, would get fifty cents. But, if neither one of them bugged me or fought or tattled on each other, they would each get a dollar. I explained how they would have to work together to not bug each other, and to mediate disagreements by themselves. What followed was the most peaceful day I can remember in a long time! There was zero bickering, none! They each got their dollar and I told them the same deal would be on for the next day. And the next. And the next. Principles, schminciples. $14 a week is a cheap price to pay for peace and quiet.

Basically, this is the Prisoners' Dilemma in reverse; also known as the "moral hazard in teams" problem. The idea is that to get a team (in this case children) to do something, you reward the team. Of course, what is interesting is that as well as the collective bonus, there was a fall-back. The fall-back is the hard one to monitor but thanks to the broader incentive she didn't seem to get there.

The alternative to this is 'joint punishment.'