This is a chamber in which Skinner placed animals such as rats and pigeons to study. The chamber contains either a lever or key that can be pressed in order to receive reinforcements such as food and water. To get a rat to learn how to press a lever, the experimenter will use small rewards after each behavior that brings the rat toward pressing the lever. When it takes a step toward the lever, the experimenter will reward the behavior by presenting food or water in the dish. Then, when the rat makes any additional behavior toward the lever, like standing in front of the lever, it is given a reward. The rat will no longer get a reward for just taking a single step in the direction of the lever. This continues until the rat reliably goes to the lever and presses it to receive reward.