Classical Conditioning
Modified: 2024-12-25 7:22 AM CST
-
Ivan Pavlov was a Russian physiologist.
- During the early 20th century
he worked on describing the process of digestion.
- He developed
techniques of collecting saliva from dogs.
- He did so because
salivation is the first step in digestion.
- He presented meat powder
to his dogs, and then collected the saliva.
- However, he soon noticed
that as the dogs became familiar with the experimental routine they
began to salivate before they received the meat powder.
- That observation led Pavlov to investigate the process whereby
dogs learned to associate the experimental routine with the meat
powder.
- That decision marked the time that Pavlov's research became
psychological instead of physiological.
- He systematically presented
stimuli, e.g., metronomes, lights, buzzers, to his dogs and then
followed those with meat powder.
- He soon found that the dogs easily
learned to salivate to the presentation of any stimulus associated
with the meat powder.
- He called the meat powder the unconditioned stimulus or UCS, because dogs did not need to learn that association.
- It was already
"built-in" to each dog.
- He called the stimulus he chose to present
first the conditioned stimulus or CS.
- He called it the conditioned
stimulus because the dogs would not salivate to it at first.
- They
would only salivate to it after it had been associated with the UCS.
- When the dog salivated to the meat powder, Pavlov called that
response the unconditioned response or UCR.
- He called it that because
it occurred to the UCS.
- When the dog salivated to the stimulus Pavlov
chose and presented prior to the UCS, he called that the conditioned
response or CR.
- Again, he called it that because it occurred to the
CS.
- Although the UCR and CR are very similar, they are not identical.
- So, Pavlov's discovery was that a new stimulus can lead to a new
response similar to a naturally occurring stimulus and response.
- The
keys to classical conditioning are the temporal (time) relationships
of the CS and the UCS, and also, how well the CS predicts the
likelihood of the UCS.
- Let us review. Pavlov's discovery is now called classical or
respondent conditioning.
- The UCS-->UCR relationship is naturally
occurring; it is not learned.
- Salivation in dogs occurs to the
presentation of meat powder because that is part of the biology of
being a dog.
- A similar example in humans is an air puff to the eye
following the presentation of a light.
- Humans will blink if air is blown gently into their
eye. (UCS->UCR)
- The CS (the light) at first leads to no observable behavior.
- But, as the CS
is followed by the UCS over and over, do humans start to salivate when the
CS is presented,; they blink to a light when
that light (a CS) is presented prior to the puff of air.
- So, one can think of classical conditioning as the pairing of a
CS and a UCS in time, with the CS occurring first, or, CS-->UCS.
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