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Copyright 2013-2014
Learning
Learning is one of those concept whose meaning is crystal clear
until one has to put it in actual words "Learning is when you
learn something."
Learning is any relatively permanent change in behaviour
brought about by experience or practice.
Relatively permanent means that when people learn anything,
some part of their brain is physical changed to record what they
have learned.
This is actually process of memory, for without the ability to
remember what happens, people cannot learn anything.
Research suggests strongly that once people learn something, it
is always present somewhere in memory, They may be unable to
"get" to it but it's there.
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DEFINITION
Association
• Association: linking two events or stimuli that
occur together in space or time. Early theories
of learning were based on principles of
association.
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– Classical Conditioning
– Operant Conditioning
Classical Conditioning
• Ivan Pavlov..
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– Learning that results from pairing two events in
the environment.
– Learn to associate a neutral event with another
event or stimulus from the environment.
Cont…
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• Studying the digestive system in his dogs, Pavlov had built a
device that would accurately measure the amount of saliva
produced by the dogs when they were fed a measured amount
of food.
• Normally, when food is placed in the mouth of any animal, the
salivary glands automatically start releasing saliva to help with
chewing and digestion.
• The food causes a particular reaction, the salivation. A stimulus
can be defined as any object, event, or experience that causes
a response, the reaction of an organism. In the case of Pavlov's
dogs, the food is the stimulus and salivation is the response.
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Before Conditioning
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During Conditioning
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After Conditioning
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Conditioning Process
Cont…
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• Pavlov spent the rest of his career studying what eventually
he termed classical conditioning, learning to make a reflex
response to a stimulus other than the original, natural
stimulus that normally produces it.
Cont…
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• Elements of Classical Conditioning :
Neutral
Stimulus : Stimulus that has no effect on the desired
response.
• Unconditional stimulus (UCS) a naturally occurring
stimulus that leads to an involuntary response (food).
• Unconditional response (UCR) a naturally occurring
stimulus that leads to an involuntary response.
• An involuntary response to a naturally occurring or
unconditional stimulus (salivation).
Cont…
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• Conditioned Stimulus (CS) : Stimulus that
become able to produce a learned reflex
response by being paired with the original
unconditional stimulus.
• Conditioned Response (CR) : Learned reflex
response to conditioned stimulus.
• B.F. Skinner:
Learning that relies on associating behavior with
its results or consequences.
Defined as “operant” – animal is operating on
environment – not passive like CC (classical
conditioning).
Highlights importance of reinforcement &
punishment in learning.
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Operant Conditioning/ Instrumental
learning
Cont…
 Operant Conditioning
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The response is made first,
then reinforcement follows.
Cont…
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• Operant Conditioning also referred to as
instrumental conditioning – organism learns to
engage in certain behaviour because of the
effects of that behaviour.
• In Operant Conditioning organisms engage in
operant behaviour that result in desirable
consequences.
EXPERIMENT ON CATS
• Thorndike set up a problem that he called a puzzle box which he used to
study the learning in cats. The box was closed but it had a door which could
only be opened by performing an apparently unconnected activity like pulling a
string.
• Thorndike watched the cats gradually learn how to get out of the box by 'trailand-error' learning.
• As the cat moved about in the box, trying to escape, sooner or later it would
accidentally pull the string, and the door would open.
• When the cat was put into the box again, the time between it being put in and
finally pulling the string would gradually get shorter, until eventually the cat
would pull the string as soon as it was put in the box.
• According to Thorndike, through trial and error the cat had learned the
"correct" response, which brought it the satisfaction of escape. The cat's
escape served as a reward that strengthened or "stamped in" the correct
response : other responses, which brought no reward, were eventually
"stamped out".
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Instrumental Conditioning : Trial & Error learning.
Skinner Box
• Skinner experiment, a hungry animal (usually a laboratory set) is
put into the box. Because it is hungry, it is very active, and
wanders around the box, exploring.
• As it wanders, at some point it accidentally presses the lever, and
a pallet of food is delivered. Often, the rat does not find the food
immediately, but it does eventually.
• Very gradually, the rat builds up a connection between pressing
the lever and getting the food reward, in the same way that
Thorndike's cats learned to let themselves out of the box. When
the animal is pressing the lever frequently, and examining the food
delivery after lever-pressing, then we know that it has 'learned' the
activity.
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• Like Thorndike's 'puzzle box', Skinner developed a piece of
equipment for studying learning. This is called the 'Skinner box',
and is an attempt to reduce all those things that might affect
learning in different ways, down to almost nothing, so that the
actual learning can be studied in detail.
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Operant Conditioning
Procedure
• a. Shaping:
Conditioning procedure that uses reinforcers to guide
behavior closer to desired behavior.
• b. Reinforcer:
Anything that increases the frequency of the
preceding response or strengthens behavior.
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– successive approximations
Operant Conditioning
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• b. Reinforcers
i. Positive reinforcers: strengthens response by
presenting stimulus after response.
ii. Negative reinforcers: strengthens response by
removing an avoidance stimulus after a response.
iii. Punishment: strengthens response by presenting
negative stimulus after a response.