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History and Systems of Psychology PSY502

Lesson 11

RUSSIAN CONTRIBUTIONS

Ivan Pavlov

Ivan Pavlov is one of the greatest psychologists of 20th century. His contributions to psychology

formed the basis of many later discoveries in the field. Pavlov was born in Ryazan, Russia in 1849 and he

died in 1936. His father was a man of church therefore Pavlov started off by studying religion. He later

went on to study medicine. Initially he worked as a research associate at Leipzig, Germany, where later the

first psychological laboratory was established. At a very young age, after working at Leipzig, Pavlov was

appointed as a professor at the Imperial Institute of Experimental Medicine.

One of the greatest achievements of Ivan Pavlov was his research on digestive glands of human

beings. When published, this research was regarded very highly in the academic circles. Ivan Pavlov has the

honor of being the first and only psychologist who has ever received a Noble Prize. He was awarded the

Noble Prize in Physiology and medicine in 1904 for his work on the digestive system. As the Soviet

Revolution took place in 1917, the chances of any further research work being done by Pavlov became

meek, as it was expected that the new government would not allow Pavlov to continue with the research.

On the contrary, the new Soviet Government supported Pavlov. The government not only provided funds

to Pavlov for his research, but also provided any necessary facilities that were needed to carry out the

research.

One of the major contributions of Ivan Pavlov is that he began to see the linkage of physiology and

psychology. This means that the physiology of a person, that is the way a person is made up, or the general

structure of a person and his mind are linked up. They both influence each other. This finding of his was

published in his book in 1923. This book was also highly regarded in the academic circles. This was the

book in which Pavlov presented his ground breaking theory, and his most important contribution to the

field of psychology; the concept of learning by conditioning. It has been elaborately explained in his book.

It is actually the explanation of the link between psychology and physiology that Pavlov had discovered.

Earlier Pavlov had studied the ideas put forwarded by Sechenov, another Russian psychologist, and was

greatly impressed with them.

Pavlov conducted a series of experiments on animals and humans. His experiments of dogs

resulted in the discovery of learning by conditioning. His concept of learning by conditioning was explained

by him using the following basic terms:

a) Reflex

Reflex may be defined as an unlearned or an automatic response of the organism to a stimulus. For

example, when a puff of air strikes the eye, the eye blinks; when a person touches something hot, he

immediately withdraws his hand etc. In these examples, the puff of air and the hot object become the

stimulus while the response is the blinking of the eye or withdrawing of the body. Importantly all these

actions are involuntary and a natural reaction of the body towards stimuli. This reaction is what has

been termed by Pavlov as reflex.

b) Unconditioned stimulus (UCS)

It is a stimulus that elicits a natural response. In other words, it is a stimulus which causes the body to

respond to itself, although the body is not conditioned to it. For example, when a bell rings, a dog

which is able to hear the sound of the bell pricks his ears in response to the bell. Therefore, the dog

responds to an unconditioned stimulus. The dog has not learnt to respond to the stimulus in that

manner.

c) Unconditioned response (UR)

It is a natural response of an organism to an unconditioned stimulus. For example, when a dog looks at

food, its mouth starts to salivate. This means the stimulus that the dog has received from the

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History and Systems of Psychology PSY502

environment, it is not conditioned, but the dog reacts in a certain manner to the unconditioned

stimulus.

d) Conditioned stimulus (CS)

According to Pavlov, when we combine a neutral stimulus with an unconditioned stimulus, it evokes a

different response. This response has been termed as Conditioned Response which is a result of the

conditioned stimulus. The conditioned stimulus is when a dog is presented with the ringing of a bell

along with food. This is expected to cause the effect of salivation in the dog's mouth. In other words,

the stimulus of food has been conditioned using the stimulus of the ringing of bell.

e) Conditioned response (CR)

As the conditioned stimulus is given to the organism, it reacts in a certain manner, which is known as

the conditioned response of the organism. In the previous example, a dog was presented with the

stimulus of the ringing of a bell and that of food. This resulted in salivation in the mouth of the dog.

But later, if the dog is presented with the stimulus of the bell alone, it is expected to salivate. This

means that the response of the dog has been associated with the conditioned stimulus rather than the

original stimulus of the food. The dog would give the same response as it gave to the stimulus of the

food.

Based upon these basic elements, Pavlov put forward the idea of how animals and human beings

learn. According to him, when an unconditioned stimulus and a conditioned stimulus are repeatedly

presented together and they invoke an unconditioned response, it would later result in, that only the

presentation of a conditioned stimulus evokes the same response as before.

In simple terms, considering the example given earlier, if ringing of a bell and food are presented

together to a dog, and these lead to salivation, after repeated trials when the bell alone is rung, it evokes the

response of salivation because the dog has learnt to expect food with the ringing of bell. This is how Pavlov

showed by his experiments that animals and humans learn. Based upon his experiments he also formulated

some principles of learning which are as follows:

Acquisition

According to Pavlov, learning in humans and animals takes place when the paired stimuli results in a

response from the organism and the response is reinforced. That is if a dog is presented with food and

ringing of bell at the same time, it results in learning of a certain response by the dog.

Extinction

If the conditioned response is not reinforced, the response disappears. This process is known as

extinction of the conditioned response. For example if a dog is given food with the ringing of bell and

later the dog is not given food with the ringing of bell, the dog would stop expecting food with it. This

would result in disappearing of the conditioned response of salivation by the dog.

Spontaneous recovery

When the conditioned response of an organism disappears because the conditioned stimulus is not

paired with the unconditioned stimulus, the process is extinction. The organism would not show the

conditioned response as long as the conditioned stimulus is not reinforced, but once reinforcement is

introduced, the extinguished conditioned response is quickly recovered. This means that when a dog is

not given food with the ringing of bell, it stops expecting food with it. But as soon as the ringing of the

bell is accompanied with the food, the dog again starts expecting food with the bell. This is known as

spontaneous recovery.

Generalization

According to Pavlov, when similar stimuli evoke a conditioned response, it is a case of generalization.

This means the dog which shows the conditioned response of salivating on the ringing of bell, when

presented with a similar stimulus of ringing; it may show the same conditioned response as before.

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History and Systems of Psychology PSY502

Discrimination

When a slightly different stimulus does not evoke a conditioned response it is a case of discrimination.

This means that for example, the dog is given the stimulus of the ringing of a bell with food using a

special type of bell. When it has learned a conditioned response, the type of bell is changed and a

similar bell is used. This then does not result in the conditioned response (salivating) of the dog. In

other words, the dog has discriminated between the two types of stimuli.

This was the theory of learning presented by Pavlov. Some other contributions of Pavlov are also of

significance in the field of psychology which shall be explained later.