Ivan Pavlov

Ivan Pavlov

'Science demands from a man all his life. If you had two lives that would not be enough for you. Be passionate in your work and in your searching.'

Web Page by: Victoria Mckay (00125652) for 175.202 Assignment 2a

Ivan Petrovich Pavlov (1849 - 1936)

Ivan Pavlov was born in Rayazan, Central Russia, the son of a poor village priest. As a result of this early religious influence, Pavlov planned to have a career in the church, a choice which his father approved as his early school performance showed no signs of brilliance.

The turning point in his life came when he read the Russian translations of scientific writings which alluded to the Darwinian theory. Needless to say Darwin's beliefs did not tie in with Pavlov's religious ideas, so he abandoned them and went to the University of St Petersburg and specialized in animal physiology and medicine.

After achieving a medical degree he became an assistant in a St Petersburg laboratory and then went on to be appointed a professor of pharmacology. At forty one years of age, he was the head of the physiology department.

Pavlov began to study Classical Conditioning at the age of fifty, and continued to study it for another thirty years.


Classical Conditioning

Pavlov's famous Classical Conditioning experiments became one of the first learning theories and contributed to the notion of psychology as an objective science. In being a physiologist, not a psychologist (he was very emphatic about this), Pavlov sought a scientific explanation of why dogs' will start salivating before they have seen food. It was found that almost any stimulus could have the same effect of salivation if paired with the presentation of the original stimulus often enough. It was this discovery gave Pavlov the Nobel Prize in 1904. This theory may seem complicated, but dont worry - it will become clear.

For the sake of quality understanding, we will look at Pavlov's famous original experiments with dogs. Pavlov noticed that sight alone of the dog's handler was enough to make the dog salivate.

To establish if there can be salivation with the pairing of a stimulus, Pavlov decided to use the bell as the Conditioned Stimulus, so-called because it was being paired with Food (US) to elicit salivation. Pavlov rang the bell, then fed the dogs'. After doing this repeatedly, the pairing of food and bell eventually established the dog's Conditioned Response of salivating to the sound of the bell. After repeatedly doing this pairing, Pavlov removed the food and when ringing this bell the dog would salivate. The key is that the food and bell have to be paired often enough, so that the dog coul learn to associate the bell with food. - Classical Conditioning.

Food is the Unconditioned Stimulus (US). This means that the food causes the response of salivation without previous learning.

Bell is the Conditioned Stimulus (CS). This is the stimulus which is paried with the food to make the dog eventually salivate to just the sound of the bell alone.

Salivation is initially the Unconditioned Response (UR) when paired with the food (US), and eventually becomes the Conditioned Response (CR) when paired with the bell.

Why? - Explanations for Stimulus - Response Associations:

Reinforcement: This term applies to operant conditioning which was developed by Behaviorist B.F. Skinner and focuses more on the effects of a stimulus. There is positive reinforcement and negative reinforcement, in Pavlov's experiment, food acts as the positive reinforcement. The reward of food increases behavior.

Contiguity: This is an explanation which Pavlov believes is correct. It is when the two events, food and bell, are paired together and behavior changes so that the dog salivates to both food and the sound of the bell. Another term for this is Simultaneous Conditioning.

Variability in Contiguity:

In Classical Conditioning, contiguity does not mean that the CS and US start and end at the same time. Interestingly this is not the most effective way of learning. The most effective way is Delayed Conditioning. Delayed Conditioning occurs when the bell (CS) is presented before the US and keeps going until the US is finished.

Trace Conditioning: Here the bell starts and ends before the US. There is a very short period between the two which keep them separate. However if the time period is longer then half a second, then trace conditioning is not very effective.

Backward Conditioning: is the opposite of Trace Conditioning. The food is shown before the bell with a time lapse between them. This has always been thought of as even less effective then Trace Conditioning. In an exeperiment by Keith-Lucas and Guttman (1975) however, experiments through Classically Conditioning rats by shocking them electrically (US) prior to presentation of hedgehog have shown that Backward Conditioning can be successful.

Higher-Order Conditioning: Here is an ongoing process of Classical Conditioning. Once Pavlov proved that a bell could can become a Conditioned Stimulus, he then paired this with another neutral stimulus - a black triangle which when paired with the bell often enough also illicited the response of salivation. 'In people, words and complex thoughts can be stimuli which can illcit very powerful emotional responses through higher-order conditioning.' (Mischel, 1986 p.281)

Can you be Unconditioned?

Extinction: Pavlov found that Classical Conditioning is very robust. When the dog was not near a bell for months, but was then confronted with it again, the same repsonse of salivation happened. However, this response could be eradicated by presenting the bell (CS) without the food (US), eventually the dog will become desensitized to the bell and no longer salivated.

Recovery: However, if the bell is presented at a later time, the dog will salivate but weakly - this is called spontaneous recovery. To completely make the dog stop salivating it would be neccessary to repeat the extinction process several times over.

Acquisition: to acheive the Conditioned Response, Pavlov found that it requires more then several pairings of the food (US) and bell (CS). The more frequently they are paired, the stronger the response and this would lead rapidly to a peak at which it was the strongest, and then it would level off.

Application: In Everyday life and Psychotherapies.

Now for an interesting part of Classical Conditioning; its part in a our day to day life, and the related methods that are used for therapy - counterconditioning.

Everyday life: Classical Conditioning can help to explain the simple things in life such as a person's reaction to a particular song, or smell as well as larger emotional problems such as fear and anxiety. Pavlov's dogs have explained why cats run to the kitchen simply at the sound of a Can Opener. Likewise, the family dog knows that he/she is going to be taken for a walk by the answer phone being switched on or the owner walking to where the leash is kept. Classical Conditioning also illustrates why a person may react in a peculiar way when a particular song is being played. Further investigation may find that a good or bad experience may have occurred for that person when the song was playing.

Psychotherapy:Classical Conditioning helps us to understand some fears and anxiety and points the way to finding a solution. For example, if a person associates the experiences of being bitten by a dog with going outside, the person my develope agoraphobia (fear of open spaces). This can be especially intense if the person keeps re-living the dog bite in his/her mind. Joseph Wolpe developed a technique called Systematic Desensitization, which is based on the process of pairing a new response with an old stimulus. Desensitization is developed to associate relaxation with the stimulus that had once induced fear and anxiety. Wolpe taught anxious clients to be physically relaxed then to slowly imagine themselves closer and closer to approaching the anxiety - provoking stimulus - all the while the client is to stay relaxed. The next step in Wolpe's process is for the person to move closer to the stimulus in real life.

Another technique of counterconditioning is Aversion Therapy. This is a behavior therapy with which an aversive stimulus is paired with a stimulus that induces an undesirable response (Weiten, 1998 p.617). For example, in therapy, alcoholics have their drinks paired with an emetic drug which causes nausea and vomiting. A conditioned response is created of aversion to alcohol through this pairing. Other behaviors which have been eliminated successfully with this method are drug abuse, sexual deviance, gambling and over eating.


Corsini, R.J. & Wedding, D. (1995). Current Psychotherapies. U.S.A: Peacock Publishers, Inc.

Jones, S.L. & Butman, R.E. (1991). Modern Psychotherapies. U.S.A. Library of Congress Cataloging-in-Publication Data.

LeFrancois, Guy R. (2000). Theories of Human Learning. U.S.A. Wadsworth/Thomas Learning.

Mischel, Walter. (1986). Introduction to Personality: A New Look. Japan. CBS College Publishing.

Weiten, W. (1998). Themes and Variations. 4th ed. Pacific Grove, California. Brooks/Cole Publishing Company.