 |
| Classical Conditioning |
When you are pinched, you feel
pain; you react in some way that is unlearned. For example, someone flashes a
light and then he/she pinches you; if he/she does this for several times, you
come to feel a facsimile of the pain when the light is flashed before you are
pinched or even you are not pinched. This latter reaction is a learned
reaction. Psychologists explain this (learned reaction) in terms of
conditioning a simple form of learning.
Conditioning is of two types:
1. Classical Conditioning
2. Instrumental Conditioning or
Operant Conditioning.
Classical Conditioning:
Classical conditioning is a
form of learning in which two stimuli are presented together and the response
originally elicited by one of them comes to be elicited by the other stimulus.
It has its origin in the experiments of Russian Psychologist I. P. Pavlov who
is known primarily for his work in classical conditioning.
Pavlov, who was born on 26th
September 1849, encountered the phenomenon of conditioning during his studies
on the digestive process for which he was awarded the Nobel Prize in 1904.
Thus, Pavlov became the first Russian Nobel laureate. After the completion of
his doctorate, Pavlov went to Germany to study at Leipzig.
The food causes a particular
reaction, the salivation. A stimulus can be defined as any object, event or
experience that causes a response. Food is a natural stimulus to evoke
salivation in dog; for example, in the case of Pavlov’s dogs, the food is the
stimulus and salivation is the response.
At the beginning of his
experiments, Pavlov began by a sound of bell and recording a dog’s response. As
expected, there was no salivation. At this point, the bell was a “Neutral
Response” because it brought forth no salivation.
Then, Pavlov fed the dog, the
response was salivation. The food was an “Unconditioned Stimulus” (US) because
no prior training or conditioning was needed to establish the connection
between food and salivation. In this case, the salivation was an “Unconditioned
Response”, because it occurred automatically without any conditioning.
Using these three—the food, the
salivation, and the bell, Pavlov demonstrated that a dog could be conditioned
to salivate after hearing the bell. He did this by pairing of sound of bell
with the food. At the beginning of the experiments, he sounded the bell and
then quickly fed the dog. After Pavlov repeated this several times, the dog
began to salivate after hearing the sound of bell, but before receiving the
food. Here, the sound became a “Conditioned Stimulus” (CS) that could bring
forth salivation by itself. The response of salivating was called a
“Conditioned Response” (CR).
Elements of Classical Conditioning:
Pavlov identified several key
elements that must be present for conditioning to take place. Following are the
key elements:
Unconditioned Stimulus (US): It is the original naturally occurring stimulus which leads
to reflex or involuntary response. In case of Pavlov’s dogs, food is the
unconditioned stimulus.
Unconditioned Response (UR): It is the reflex response to the unconditioned stimulus. In
case of Pavlov’s experiment, salivation to food is the unconditioned response.
Conditioned Stimulus (CS): Pavlov determined that almost any kind of stimulus could
get associated with the unconditioned stimulus. In case of Pavlov’s experiment,
bell was the neutral stimulus because it had no effect on salivation. After
being paired with food, so many times, the bell came to produce the same
salivation response. The neutral stimulus can now be called conditioned
stimulus.
Conditioned Response: It is a learned response to the previously neutral stimulus
that has changed into conditioned stimulus. In case of Pavlov’s experiment, the
salivation on hearing the sound of bell is conditioned response.
Other Processes in Classical Conditioning:
Generalization: Pavlov
discovered that if an animal is conditioned to salivate at the sound of a bell,
it would salivate at the sound of a buzzer. The dog tended to generalize the
conditioned response to other stimuli that were somewhat similar to the
original conditioned stimulus. This process is called generalization, because
the conditioned response of salivation generalized or occurred in the presence
of similar stimuli.
Discrimination: It is the process of learning to make one response to one
stimulus and a different response or no response to another stimulus. Pavlov
could also teach the dogs discrimination; Pavlov trained the dogs to respond to
one tone, but not to respond to other tones that are similar. Pavlov did so by
making sure that food always followed only one tone, and not any others.
Extinction: It occurs when a conditioned stimulus (for example, bell)
is presented repeatedly, but is not followed by the unconditional stimulus
(such as, food). Then, the conditioned response (salivation) gradually fades
away and finally it extinguished and disappears altogether. A response is set
to be forgotten over time when there is no explicit procedure involved.
