FTA: "Our daughter realized that by holding back, she could convert one trip to the toilet into two or three, and thus triple her frog consumption. The economist Tim Harford likens this effect to the way pole-vaulter Sergei Bubka, who was paid a cash bonus each time he broke the world record, chose to do it a centimeter at a time. That’s the risk you face when you set down clear, objective rules for rewards: you often get what you pay for."