100 Things Every Designer Needs to Know About People, 2nd Edition

51 Variable Rewards are Powerful

If you studied psychology in the twentieth century, you may remember B. F. Skinner and his work on operant conditioning. Skinner studied whether behavior increased or decreased based on how often, and in what manner, a reinforcement (reward) was given.

What the Casinos Know

Let’s say you put a rat in a cage with a bar. If the rat presses the bar, he gets a food pellet. The food pellet is called the reinforcement. But what if you set it up so that the rat does not get the food pellet every time he presses the bar? Skinner tested various scenarios and found that the frequency with which you gave the food pellet, and whether you gave it based on elapsed time or bar presses, affected how often the rat would press ...