LEARNING
IVAN SUNEEL SAMUEL
Lecture
Forman Christian College
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Classical Conditioning
• Learning refers to a relatively durable
change in behavior or knowledge that is
due to experience.
• Classical conditioning is a type of learning
in which a stimulus acquires the capacity
to evoke a response that was originally
evoked by another stimulus.
• It was described by Ivan Pavlov hence, is
also called Pavlovian conditioning.
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Classical Conditioning…..
• Terminology and procedure:
We will look at some of the basic terminology:
Unconditional Stimulus (UCS) is a stimulus that evokes
an unconditional response without previous conditioning.
Unconditional response (USR) is an unlearned
reaction to an unconditioned stimulus that occurs without
previous conditioning.
Conditioned stimulus (CR) is a previously neutral
stimulus that has, through conditioning, acquired the
capacity to evoke a conditioned response. The
conditioned response (CR) is a learned reaction to a
conditioned stimulus that occurs because of previous
conditioning. (The UCR and the CR could be the same).
A trial in classical conditioning consists of any presentation
of stimulus or pair of stimuli.
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Classical conditioning…..
NS (tone) → No response
UCS (Meat powder) → UCR (Salivation)
NS (tone) → No response
UCS (Meat powder) → UCR (Salivation)
CS (Tone) → CR (Salivation)
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Basic processes in CC
•
Acquisition refers to the initial stage of learning something.
•
Stimulus contiguity is important but learning theorists now realize that
contiguity alone doesn’t automatically produce conditioning.
•
Timing (1. simultaneous, 2. short delayed (1/2 sec), 3. trace conditioning).
• Extinction: the gradual weakening and disappearance of a
conditioned response tendency.
• Spontaneous recovery: is the reappearance of an extinguished
response after a period of non-exposure to the conditioned
response.
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Generalization & Discrimination
• Stimulation generalization occurs when an organism
that has learned a response to a specific stimulus
responds in the same way to new stimuli that are similar
to the original stimulus.
• Stimulus discrimination occurs when an organism that
has learned a response to a specific stimulus does not
respond in the same way to new stimuli that are similar
to the original stimulus.
• Higher order conditioning in which a conditioned
stimulus functions as if it were an unconditioned
stimulus.
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Operant Conditioning
• Operant conditioning is also called instrumental
learning and was first introduced by Edaward Thorndike.
• According to the law of effect, if a response in the
presence of a stimulus leads to satisfying effects, the
association between the stimulus and the response is
strengthened.
• Reinforcement occurs when an event following a
response increases an organism’s tendency to make
that response.
• Reinforcement contingencies are the circumstances or
rules that determine whether responses lead to the
presentation of reinforcers.
• Skinner Box
• Shaping consists of the reinforcement of closer and
closer approximations of a desired response.
• Extinction
• Resistance to extinction
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Intermittent Reinforcement
• A schedule of reinforcement determines which occurrences of a
specific response result in the presentation of a reinforcer.
• Continuous reinforcement
• Intermittent or partial reinforcement
• Ratio schedules require the organism to make the designated
response a certain number of times to gain each reinforcer.
With fixed ratio schedule, the reinforcer is given after a fixed number
of nonreinforced responses.
With variable ratio schedule, the reinforcer is given after a variable
number of nonreinforced responses.
• Interval schedules require a time period to pass between the
presentation of reinforcer.
With a fixed interval schedule, the reinforcer is given for the first
response that occurs after a fixed time interval has elapsed.
With a variable interval schedule, the reinforcer is given for the first
response after a variable time interval has elapsed.
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Positive and Negative
Reinforcement
• Positive reinforcement occurs when a
response is strengthened because it is followed
by the presentation of a rewarding stimulus.
• Negative reinforcement occurs when a
response is strengthened because it is followed
by the removal of an aversive stimulus.
• Punishment occurs when an event following a
response weakens the tendency to make that
response.
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Biological Constraints on
conditioning
• Instinctive Drift: Instinctive drift occurs
when an animal’s innate response
tendencies interfere with conditioning
processes.
• Preparedness (Seligman, 1971) involves a
species specific predisposition to be
conditioned in certain ways and not others.
• Evolutionary perspective on learning
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Observational Learning
• Observational learning occurs when an
organism’s responding is influenced by the
observation of others, who are called as models
(Bandura, 1977).
• Basic Processes
1. Attention
2. Retention
3. Reproduction
4. Motivation
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