Quick Fact
The term 'extinction' was first used by renowned Russian physiologist, Ivan Pavlov, in course of his research on classical conditioning.

So we know that Ivan Pavlov successfully conditioned his dog to salivate at the sound of a bell. But have you ever wondered what must have happened next? What must have happened when the dog repeatedly heard the bell, but never got food? In course of his research, Pavlov observed that the dog would stop salivating at the sound of the bell, if it was no longer followed by food. He called this 'extinction'.

What is the Process of Extinction in Psychology?

In behavioral psychology, extinction is weakening of a conditioned response (CR) over the course of time, eventually resulting in the said behavior either decreasing or disappearing. While the concept is seen in different types of behavioral conditioning―the case of Pavlov's dog is an example of extinction in classical conditioning―it is more often associated with operant conditioning.

Extinction in Operant Conditioning

In operant conditioning, the focus is on reinforcement and punishment to change the behavior, i.e., to increase a particular behavior or to get rid of unwanted behavior. In this case, extinction occurs when the positive reinforcer that triggers or maintains the target behavior is removed. It is usually the case when the reinforcement used is no longer rewarding, but can also happen if the target behavior is no longer reinforced.

In the Skinner Box experiment, for instance, when the rat keeps on pressing the lever (target behavior), but doesn't receive food (stimulus), he simply stops pressing it.

Example 1
The first time you go to a grocery store with your child, he asks you to buy a candy. At first, you refuse, but when he starts crying, you buy him a candy. This reinforces the idea in his mind that every time he throws a tantrum at the grocery store, he will get a chocolate. He continues to this, and you unknowingly continue to reward his behavior. Then one fine day, you simply say 'no' to his demand despite his tantrums. He cries, but you ignore. This is repeated on the next two occasions and finally, when you go to the store the third time, you realize that he is no longer throwing tantrums.

Example 2
In the classroom, the teacher praises the child who tops the class. This prompts the child to work hard and try to fare better with every subsequent test. Over a period, the teacher stops praising the child and as a result, the child doesn't feel like working hard. In this example, you see that the subject stops focusing on the target behavior as the reinforcement is no longer rewarding.

Extinction in Classical Conditioning

Unlike in the case of operant conditioning, in classical conditioning, extinction occurs when the unconditioned stimulus does not occur after the conditioned stimulus is presented over time. Let's once again take the famous case of Pavlov's dog. When the conditioned stimulus (CS), which was the sound of the bell, was presented alone repeatedly, it stopped predicting the occurrence of unconditioned stimulus (US), which in this case was the food, and as a result, the conditioned response (CR), i.e., salivation, stopped.

Example 1
Let's say your professor has the knack to surprise you with tests every once in a while. On a couple of occasions, you notice that the day he takes a 'surprise test', he carries a particular book along with him. The book, thus, becomes the conditioned stimulus, which invokes the fear of tests (conditioned response) in your mind, regardless of whether he is actually taking a test or not. However, if a test, which happens to be the unconditioned stimulus here, no longer follows the conditioned stimulus, then the fear disappears.

Example 2
Yet another textbook example of extinction in the context of classical conditioning would be the story of the boy who cried wolf. In this case, the 'boy crying wolf' was the conditioned stimulus, the 'wolf coming' was an unconditioned stimulus, while the 'villagers running to rescue the boy' was a conditioned response. When the unconditioned stimulus (wolf appearing) didn't follow the conditioned stimulus (boy crying wolf) on a couple of occasions, then the villagers simply stopped responding.

Extinction Vs. Unlearning

It's important to note that extinction is not the same as unlearning. At times, the conditioned response may suddenly reappear after decreasing or disappearing for sometime in what is known as spontaneous recovery.

Let's say your dog normally follows you to the kitchen for food after you return from your morning walk. All of a sudden, one day, you see that the dog stops following you to the kitchen and instead, goes to his kennel when you are back. This is repeated for 3 - 4 days, and then again one day, suddenly, he is back to following you to the kitchen for his reward. So, even though it may appear as if the subject has forgotten the link between the conditioned stimulus and conditioned response, that is not the case.