Rewards don't bring about the changes we are hoping for, but the point here is also that something else is going on: the more rewards are used, the more they seem to be needed. The more often I promise you a goody to do what I want, the more I cause you to respond to, and even to require, these goodies. As we shall see, the other, more substantive reasons for you to do your best tend to evaporate, leaving you with no reason to try except for obtaining a goody. Pretty soon, the provision of rewards becomes habitual because there seems to be no way to do without them. In short, the current use of rewards is due less to some fact about human nature than to the earlier use of rewards