“You may not like this idea; none of us wants to admit that we are pack animals. But in a complicated world, running with the herd can make sense. Who has time to think through every decision and all the facts behind it? If everybody around you thinks that conserving energy is a good idea – well, maybe it is. So if you are the person designing an incentive scheme, you can use this knowledge to herd people into doing the right thing – even if they’re doing it for the wrong reasons.”