Ivan Pavlov, a Russian physiologist, is renowned for discovering classical conditioning through his experiments with dogs, particularly focusing on their salivary responses to food stimuli. He demonstrated that dogs could learn to associate a sound (bell) with food, leading to salivation even in the absence of food, a process he termed conditioned reflex action. Pavlov's groundbreaking work in this area earned him the Nobel Prize for his research on the physiology of digestion.

2. IVAN PAVLOV
a. Ivan Petrovich Pavlov, a Russian citizen, was basically a
physiologist known for his discovery of classical conditioning
through his experiments with dogs.
b. Pavlov was nominated over four successive years for the
Noble Prize in Physiology or Medicine. When Pavlov received
the Noble Prize it was specified that he did so “in recognition
of his work on the physiology of digestion”.
c. Pavlov carried out his classical experiments on the
digestive glands, which would eventually grant him the
aforementioned Noble Prize.

3. IVAN PAVLOV’S STUDY
a. Ivan Pavlov studied the excretion of
saliva in the digestive system of the
dog.
b. He observed in his study that the
excretion of saliva increased in the
dog when it saw the food.
c. A few days later, he observed that on
hearing the footsteps of the person
bringing food, its saliva started to
excrete and it was all the more on
seeing the food.
d. This response of the dog (response-R)
towards the food stimulus(stimulus-S)
turned him to the psychological study.

4. PAVLOV’S EXPERIMEMT
a. Pavlov prepared a wooden appliance. There
was a wooden plank in the middle and there
was a window in the plank through which the
food to the dog was supplied.
b. A bell was put at one place in the appliance.
Pressing of a switch made the bell to ring and
as soon as the bell rang, the food plate
emerged before the dog.
c. He tied the hungry dog on the other side. He
placed a pipe the saliva gland of this dog by
surgery. The other end of this pipe was put
into a beaker where saliva was to be
collected.

6. EXPERMENTS RESULT
a. As soon as the dog saw the food, then its saliva started to excrete. In the
view of Pavlov, food was the natural stimulus for the dog and excretion
of the saliva was a reflex action on seeing the food.
b. In the terminology of Pavlov, for the response of excretion of saliva on
listening to the sound of the bell was an unnatural stimulus.
c. Pavlov repeated this experiment over many days, and observed after a
few days that saliva started to excrete in the dog as soon as it heard the
sound of the bell, which was still more on seeing the food.
d. After repeating this experiment over a few days, Pavlov only pressed the
switch for ringing the bell but did not present the food plate. He saw that
the saliva excreted was equal in amount to the saliva that excreted with
the sound of the bell and the food.

7. CLASSICAL CONDITIONING
a. Pavlov termed this situation of ringing of the bell as the conditioned
stimulus(CS).
b. Pavlov termed the process of making natural response for conditioned
stimulus(CS) in place of unconditioned stimulus (US) as learning.
c. Pavlov termed this type of learning as conditioned reflex action.
d. Modern psychologist call it classical conditioning.
e. After a few days he saw that there was no excretion of saliva in the dog
with the sound of the bell. Pavlov termed this process as extinction.

8. CLASSICAL CONDITIONING THEORY
a. There is an unconditioned response(UR) for any unconditioned
stimulus(US), which is called reflex action.
UR(excretion of saliva)------- US(food)
b. Unconditioned response(UR) occurs presenting a conditioned
stimulus(CS) and unconditioned stimulus(US) together.
CS(BELL)+US(FOOD)-----UR(SALIVA)
c. Conditioned stimulus(CS)-----UR or CR (He used the termed
conditioned response in place of UR in response to CS.
Relationship between CS and CR was called by Pavlov as conditioned
reflex (CLASSICAL CONDITIONING)
d. CS remains effective only for a limited time.

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