People tend to exert more effort as they get closer to their goals. Companies can take advantage of this by designing a customer rewards program that makes the perceived distance to the reward seem small
In a classic experiment in the 1930s, behaviorist Clark Hull observed that rats on a straight runway ran faster as they moved closer to the food box. Knowing the reward was almost at hand presumably motivated the rats to work harder, a phenomenon that Hull called the "goal-gradient" hypothesis.
[This article has been reproduced with permission from Capital Ideas, the research journal of University of Chicago's Booth School of Business http://www.chicagobooth.edu/capideas/ ]