Understand why shaping is necessary for conditioning some behaviors.
Describe the basic procedures of shaping.
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1. In operant conditioning, when a particular behavior is followed by reinforcement, the behavior will be strengthened and will occur more frequently in the future. It’s easy to use operant conditioning to train a chicken to peck at an object, or a raccoon to dip an object in water, because these animals commonly perform behaviors similar to the target behavior.
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2. But how can you condition an animal or person to perform an action that is not already part of their normal behavior? For example, pigeons don’t spontaneously turn in circles. How could you train a pigeon to turn in a circle?
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3. B. F. Skinner devised a solution to this problem. He called it shaping—reinforcing successive approximations to the desired behavior. By reinforcing responses that are ever closer to the final desired action, and ignoring all other responses, researchers can gradually shape complex behaviors.
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4. This technique is not limited to laboratory experiments. It is also used to train animals that perform in a zoo or circus, as well as animals that assist individuals with disabilities.
Practice: Using Shaping to Train a Pigeon
Use the STEP buttons to move through the sequence of events in this shaping simulation.
We'll begin the shaping simulation by teaching the pigeon to eat food pellets from a dispenser.
Every few seconds you should select the “Reinforcer” button. The dispenser will make a clicking noise, and one pellet will appear.
Select the “Reinforcer” button, watch what happens, repeat several times, then move to Step 2.
After a few seconds, the pigeon will get anxious, and will begin turning back and forth as it tries to understand why the food stopped.
As soon as the pigeon turns one quarter of the way to the left, you should select the “Reinforcer” button: the click will sound and a pellet will appear.
The pigeon now starts moving back and forth again, but a one-quarter turn is no longer enough. When it turns a little farther than that, select the “Reinforcer” button again. Then move to Step 3.
Little by little, the pigeon turns farther and farther, until finally it makes a complete circle. As soon as the pigeon makes a complete turn to the left, you should select the “Reinforcer” button.
From that point on, only full-circle turns receive a reinforcer.
Quiz 1
Select an answer to the question. Then, select the CHECK ANSWER button.
Quiz 2
Match the terms to their definitions by dragging each colored circle to the appropriate gray circle. When all the circles have been placed, select the CHECK ANSWER button.