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LEARNING
Dr Nesif Al-Hemiary
MBChB – FICMS(Psych)
International Associate of the RCPsych(UK)
LEARNING
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Learning is a relatively permanent change in
behavior that occurs as the result of experience.
Behavior changes that are due to maturation or
temporary conditions of the organism (such as
fatigue or drug induced states ) are not included.
Basic types of learning
1.
2.
3.
classical conditioning
instrumental( operant)
conditioning.
complex learning
Classical conditioning
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Classical conditioning is a learning process in which
a previously neutral stimulus becomes associated
with another stimulus through repeated pairing with
that stimulus.
Ivan Pavlov –Nobel prize
Pavlov’s experiment
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A researcher first attaches a fistula or tube to the dog’s salivary flow . Then
the dog is placed in front of a pan into which meat powder can be delivered
automatically.
A researcher turns on a light in a window in front of the dog. After a few
seconds , some meat powder is delivered to the pan and the light is turned
off.
The dog is hungry ,and the recording device registers copious salivation. This
salivation is an unconditioned response( an innate or unlearned response
elicited by the UCS). The meat powder is an unconditioned stimulus (a stimulus
that automatically elicits a response without prior conditioning) .The salivation
that result from exposure to meat powder is called unconditioned
response(UCR).
After a few presentations of the light followed by meat powder ,the dog will
salivate in response to the light ,even if no meat powder is delivered.
This anticipatory salivation is a conditioned (CR), and the light is a conditioned
stimulus( CS). In other words, the CR is a learned response evoked by a CS
that has come to predict the occurrence of the UCS.
Acquisition & Extinction
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Each pair of the CS and the UCS is called trial.
The trials when the organism is learning the
association between the two stimuli are the
acquisition stage of conditioning. During this stage
repeated pairings of the CS (light) and UCS (food)
strengthen the association between the two.
Extinction : represents learning that the conditioned
stimulus (CS) is no longer predicts the unconditioned
stimulus (UCS). Extinction is not the” unlearning “of
the original CS-UCS association; in fact extinction
involves the formation of a new CS- no UCS memory
that inhibits expression of the CS-UCS association.
Inhibitory conditioning
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Excitatory conditioning :the ability of a CS to increase the
probability or magnitude of a given behavior.
Inhibitory conditioning : the ability of a CS to decrease the
probability or magnitude of a behavior. This can occur, for
example , when a CS that has come to predict the occurrence of a
UCS is presented alone, as occurs during extinction.
Inhibitory conditioning also occurs when a CS that predicts a UCS
is presented with a new CS on trials in which the UCS is omitted,
for example, when a tone that predicts forefinger shock is
presented together with a light ( a compound CS presentation) in
the absence of shock, the light becomes a conditioned inhibitor
;that is, the light comes to predict the absence of shock.
Instrumental (operant)
Conditioning
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Learning of novel things is not possible by classical
conditioning.
Instrumental or operant conditioning : certain
responses are learned because they operate on, or
affect, the environment.
much real–life learning occur by this type of
learning.
The law of effect
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L.E. Thorndike ( a psychologist who is pioneer in this type of
conditioning)
the cat and fish experiment: a hungry cat is placed in a cage
whose door is held fast by a simple latch, and a piece of fish is
placed just outside the cage . Initially ,the cat tries to reach the
food by extending its paws through the bars. When this fails , the
cat moves about the cage ,engaging in a variety of behaviors. At
some point it inadvertently hits the latch, frees itself, and eats the
fish.
The researchers then place the cat back and put a new piece of
fish outside. The cat goes through roughly by the same set of
behaviors until once more it happens to hit the latch. The
procedure is repeated again and again.
Over a no. of trials ,the cat eliminates many of its irrelevant
behaviors ,and eventually it opens the latch and frees itself as soon
as it is placed in the cage .The cat has learned to open the latch to
obtain the food.
Trial and Error
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Trial-and-Error behavior: it may sound as if the cat is acting
intelligently ,but Thorndike argued that there is little “intelligence”
operating here.
There is no moment in time when the cat seems to have an insight about
the solution to its problem.
In stead the cat performance improves gradually over a series of trials.
The cat appears to be engaging in trial-and-error behavior, and when
a reward immediately follows one of those behaviors the learning of
the action is strengthened.
Thorndike referred to this strengthening as the law of effect
the law of effect selects from a set of random responses only those
that are followed by positive consequences .
This is similar to evolution (genes that promote survival or fitness are
selected across generations ).
Reinforcement
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Reinforcement : the delivery of an appetitive
stimulus or the removal of an aversive stimulus
increases the probability of a behavior.
Positive reinforcement : behavior that produces an
appetitive stimulus.
Negative reinforcement : occurs when a behavior
prevents an aversive stimulus.
Punishment
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The converse of reinforcement.
It is the process by which the delivery of an aversive
stimulus or the removal of an appetitive stimulus decreases
the probability of a behavior.
Positive contingency :behavior leads to aversive stimulus.
Negative contingency : behavior prevents an appetitive
stimulus (omission training).
Reinforcement produces GOOD outcomes.
Punishment produces BAD outcomes.
These principles can be implicated for child rearing.
The temporal relationship between a response and its
reinforcer ( immediate reinforcement is more effective than
delayed reinforcement ).
Complex Learning
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According to the cognitive perspective ,the crux of learning lies in an
organism’s ability to mentally represent aspects of the world and then
operates on these mental representations rather than on the world
itself.
In classical & instrumental conditioning what is represented is an
association between events.
In other cases what is represented seems more complex :
It might be a map of one’s environment or an abstract concept like the
notion of cause.
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The operations performed on mental representations are more complex
than associative processes. the operations may take the form of mental
trial & error , in which the organism tries out different possibilities in its
mind. Or the operations may be a strategy in which we take some
mental steps only because they make possible subsequent steps.
Cognitive maps & Abstract concepts
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Edward Tolman: his research dealt with the problems of
rats learning their way through complex mazes. In his
view, a rat running through a complex maze was not
learning a sequence of right & left turning responses but
rather was developing a cognitive map: a mental
representation of the layout of the maze.
More recent research provides strong evidence for this
view.
Experiments on rats and chimpanzees : Chimpanzees can
acquire abstract concepts that were once believed to be
the sole province of humans.
Insight learning
Insight learning involves three critical aspects:
1. suddenness
2. its availability once it is discovered.
3. transferability
 These aspects are at odds with trial & error behaviors of the type
observed by Thorndike ,Skinner, & their students.
 Complex learning involves two phases :
1. Initial phase :problem solving is used to arrive at a solution.
2. Second phase :the solution is stored in memory & retrieved
whenever a similar problem is faced.
 So, complex learning is intimately related to memory & thinking.
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