Rewarded behavior is behavior that will be repeated. It's a basic behavioral principle that people come forward to do things if they see a reward in it. For instance, salespeople sell more when the commission is juicy. Moreover, if people come to expect the reward and trust that it will be delivered, they repeat the actions that earned them rewards. This is why it is so important to understand what difficult people truly want. If you know what they're after, you can provide it to them; in exchange, you will enjoy behavior that is less difficult and more helpful for you and your colleagues.
SOURCE: Communicating in Small Groups by Steven Beebe and John Masterson (Pearson, 2003)