What if you want to reinforce a rat's behavior of pressing a lever but cannot do it because the rat never presses the lever? This is called shaping. Shaping is defined as the gradual creation of new operant behavior through reinforcement of successive approximations of that behavior. When the rat goes near the lever, we can start by adding food nearby when it stands there. After you do that, you can see the rat go over to the lever more often. We only deliver the food when it's facing the lever more. That's how the shaping works. This was identified by Skinner in 1938.