In psychology, extinction refers to the gradual weakening of a conditioned response that results in the behavior decreasing or disappearing.
In operant conditioning, extinction can occur if the trained behavior is no longer reinforced or if the type of reinforcement used is no longer rewarding.
In classical conditioning, when a conditioned stimulus is presented alone without an unconditioned stimulus, the conditioned response will eventually cease. For example, in Pavlov's classic research, a dog was conditioned to salivate to the sound of a bell. When the bell was presented repeatedly without the presentation of food, the salivation response eventually became extinct.
In operant conditioning, extinction occurs when a response is no longer reinforced following a discriminative stimulus. B. F. Skinner described how he first observed this phenomenon:
"My first extinction curve showed up by accident. A rat was pressing the lever in an experiment on satiation when the pellet dispenser jammed. I was not there at the time, and when I returned I found a beautiful curve. The rat had gone on pressing although no pellets were received. ... The change was more orderly than the extinction of a salivary reflex in Pavlov's setting, and I was terribly excited. It was a Friday afternoon and there was no one in the laboratory who I could tell. All that weekend I crossed streets with particular care and avoided all unnecessary risks to protect my discovery from loss through my accidental death."
- "Let's assume that you had the misfortune of developing a classically conditioned taste aversion to your favorite food because you ate this food just before you became ill with the flue. Furthermore, let's assume that you wanted to be able to eat your favorite food again without feeling sick to your stomach. How would you go about ridding yourself of your acquired taste aversion? One way would be to force yourself to eat the food over and over again. At first, you would feel nauseated because of the conditioning, but if you continued to eat the food, your conditioned nausea would eventually decrease, or undergo extinction."
(Pastorino & Doyle-Portillo, 2013)
- "Would a rat stop bar pressing if no more food arrived? Yes, but not immediately. Through operant extinction, learned responses that are not reinforced gradually fade away. Just as acquiring an operant response takes time, so does extinction. For example, if a TV program repeatedly bores you, watching the program will likely extinguish over time." (Coon & Mitterer, 2009)
Does the Response Really Disappear?
In research on classical conditioning, Pavlov found that when extinction occurs, it does not mean that the subject returns to their unconditioned state. Allowing several hours or even days to elapse after a response has been extinguished can result in spontaneous recovery of the response. Spontaneous recovery refers to the sudden reappearance of a previously extinct response.
In his research on operant conditioning, Skinner discovered that how and when a behavior is reinforced could influence how resistant it was to extinction. He found that a partial schedule of reinforcement (reinforcing a behavior only part of the time) helped reduce the chances of extinction.
- "With classical conditioning, there appears to be a positive relation between strength of conditioning and resistance to experimental extinction. The greater the amount of conditioning training and the larger the measures of CR magnitude, the greater the resistance to extinction. Any variable that increases the strength of a CR also increases its resistance to extinction."
- "Recently, some have argued that habituation may also play a role in extinction. According to this argument, repeated exposure to the CS causes one to habituate to it. As long as you ignore the stimulus, it is less likely to elicit a response from you, and extinction ensues. But what if you have trouble ignoring the CS? One recent study found that characteristically anxious children exhibited more fear while habituating to a loud sound than non-anxious children did. The anxious children also showed slower extinction of their fear of the sound, suggesting that personality factors may affect both habituation and extinction."
(Pastorino & Doyle-Portillo, 2013)
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Coon, D. & Mitterer, J. O. (2009). Psychology: A journey. Cengage Learning.
Kramble, S. (2007). Psychology of learning behavior. New Delhi: Global Vision Publishing House.
Pastorino, E. E. & Doyle-Portillo, S. M. (2013). What Is Psychology?: Essentials. Belmont, CA: Wadsworth, Cengage Learning.
Pavlov, I. (1927). Conditioned reflexes: An investigation of the physiological activity of the cerebral cortex. (G. V. Anrep, Trans.). New York: Dover. http://psychclassics.yorku.ca/Pavlov/index.htm
Skinner, B. F. (1956). A case history in scientific method. American Psychologist, 11, 221-233.
Skinner, B. F. (1979). The shaping of a behaviorist: Part two of an autobiography. New York: Knopf.