Download Learning - Lillian McMaster

Chapter 3
Learning and
Human Nature
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Copyright © Allyn and Bacon 2009
Learning vs. Instincts
Learning –
A process through which experience produces
lasting change in behavior or mental
processes
HabituationLearning not to respond to stimulation
InstinctsMotivated behaviors that have a strong innate
basis
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Learning
Mere exposure effect –
Learned preference for stimuli to which
we have been previously exposed
Behavioral learning –
Forms of learning that can be described
in terms of stimuli and responses
(e.g. classical and operant conditioning)
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What Sort of Learning Does
Classical Conditioning Explain?
Classical conditioning is a
basic form of learning in which
a stimulus that produces an
innate reflex becomes
associated with a previously
neutral stimulus, which then
acquires the power to elicit
essentially the same response
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The Essentials of Classical
Conditioning
Neutral stimulus –
Any stimulus that produces no
conditioned response prior to learning
Acquisition –
Initial learning stage in classical
conditioning
• conditioned response (CR) becomes
elicited by the conditioned stimulus (CS)
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Basic Features of
Classical Conditioning
Unconditioned
stimulus (UCS)
Unconditioned
response (UCR)
Conditioned
stimulus (CS)
Conditioned
response (CR)
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The Essentials of Classical
Conditioning
Unconditioned
stimulus (UCS)
Unconditioned
response (UCR)
The stimulus that elicits
an unconditioned
response
Conditioned
stimulus (CS)
Conditioned
response (CR)
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The Essentials of Classical
Conditioning
Unconditioned
stimulus (UCS)
Unconditioned
response (UCR)
Conditioned
stimulus (CS)
The response elicited
by an unconditioned
stimulus without prior
learning
Conditioned
response (CR)
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The Essentials of Classical
Conditioning
Unconditioned
stimulus (UCS)
Unconditioned
response (UCR)
Conditioned
stimulus (CS)
A previously neutral
stimulus that comes to
elicit the conditioned
response
Conditioned
response (CR)
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The Essentials of Classical
Conditioning
Unconditioned
stimulus (UCS)
Unconditioned
response (UCR)
Conditioned
stimulus (CS)
Conditioned
response (CR)
A response elicited by a
previously neutral
stimulus that has
become associated with
the conditioned stimulus
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Classical Conditioning
Prior to conditioning
Neutral stimulus
(tone)
(Orientation to sound
but no response)
Unconditioned stimulus
(food powder in mouth)
Unconditioned response
(salivation)
Conditioning
Neutral stimulus
CS (tone)
+
Unconditioned stimulus
(food powder)
Conditioned response
(salivation)
After conditioning
Conditioned stimulus
(tone)
Conditioned response
(salivation)
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Classical Conditioning
Extinction –
Weakening of a conditioned association
in the absence of an unconditioned
stimulus or reinforcer
Spontaneous recovery –
Reappearance of an extinguished
conditioned response after a time delay
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(1)
Acquisition
(CS + UCS)
(2)
Extinction
(CS alone)
Rest period
Strength of the CR
(Weak)
(Strong)
Acquisition, Extinction, and
Spontaneous Recovery
(3)
Spontaneous
Recovery
(CS alone)
(Time)
Trials
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Classical Conditioning:
Generalization and Discrimination
Stimulus generalization involves giving a
conditioned response to stimuli that are
similar to the CS
Stimulus discrimination involves
responding to one stimulus but
not to stimuli that are similar
Confusing stimuli may cause
experimental neurosis
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Applications of Classical Conditioning
Conditioned Food Aversions–
Biological tendency in which an organism
learns to avoid food with a certain sight,
smell, or taste after a single experience,
if eating it is followed by illness
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Biological Predispositions:
A Challenge to Pavlov
Garcia & Koelling (1966) findings• Selective CS-UCS connection
• Innate disposition to associations
Why are some stimuli-consequence
combinations readily learned while other
combinations are highly resistant to learning?
What any organism can or cannot learn in a
given setting is due in part to its evolutionary
history
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How Do We Learn
New Behaviors by
Operant Conditioning?
In operant conditioning, the
consequences of behavior,
such as rewards and
punishments, influence the
probability that the behavior
will occur again
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How Do We Learn
New Behaviors by
Operant Conditioning?
Trial-and-error learning –
Learner gradually discovers the correct
response by attempting many behaviors
and noting which ones produce the
desired consequences
Thorndike-law of effect
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Skinner’s Radical Behaviorism
B.F. Skinner believed that the most
powerful influences on behavior are its
consequences
“The power of reinforcement”
• reward = conditions that follow and
strengthen a response
• Operant chamber
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The Power of Reinforcement
Positive reinforcers –
Stimulus presented after a response that
increases the probability of that response
happening again
• Positive = add or apply
Negative reinforcers –
Removal of an unpleasant stimulus, that
increases the probability of that response
happening again
• Negative = subtract or remove
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Contingencies of Reinforcement:
Varying the timing and frequency of
reinforcement
Continuous reinforcement –
Reinforcement schedule in which all correct
responses are reinforced
Partial (intermittent) reinforcement –
Reinforcement schedule in which some, but
not all, correct responses are reinforced
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Schedules of Reinforcement
Ratio schedules –
Provide reward after a certain number of
responses
Interval schedules –
Provide reward after a certain time interval
Fixed Ratio (FR)
Variable Ratio (VR)
Fixed Interval (FI)
Variable Interval (VI)
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Schedules of Reinforcement
Fixed Ratio (FR)
Variable Ratio
(VR)
Fixed Interval
(FI)
Rewards appear after a
certain set number of
responses
e.g. factory workers
getting paid after every
10 cases of product are
completed
Variable Interval
(VI)
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Schedules of Reinforcement
Fixed Ratio (FR)
Variable Ratio
(VR)
Fixed Interval
(FI)
Rewards appear after a
certain number of
responses, but that
number varies from trial
to trial
e.g. slot machine payoffs
Variable Interval
(VI)
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Schedules of Reinforcement
Fixed Ratio (FR)
Variable Ratio
(VR)
Fixed Interval
(FI)
Variable Interval
(VI)
Rewards appear after a
certain fixed amount of
time, regardless of
number of responses
e.g. weekly or monthly
paychecks
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Schedules of Reinforcement
Fixed Ratio (FR)
Variable Ratio
(VR)
Fixed Interval
(FI)
Variable Interval
(VI)
Rewards appear after a
certain amount of time,
but that amount varies
from trial to trial
e.g. random visits from
the boss who delivers
praise
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The Power of Reinforcement
Primary reinforcers –
Reinforcers that fulfill basic biological
needs or desires, such as food and sex,
that have an innate basis to an organism
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The Power of Reinforcement
Secondary (conditioned) reinforcers –
Stimuli, such as money or tokens, that
acquire their reinforcing power by their
learned association with primary
reinforcers
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Factors that can influence
the effectiveness of reinforcement
Instinctive driftinnate response tendencies interfere with learned
behaviors; innate tendencies can override behaviors
learned through reinforcement
e.g., reinforcing your cat to not scratch the furniture
Premack principlea preferred activity can reinforce a less preferred
activity
e.g., children sitting quietly in class in order to go
out for recess
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Punishment
Punishment –
An aversive stimulus which diminishes
the strength of the response it follows
How does this differ from negative
reinforcement?
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Punishment vs. Negative
Reinforcement
Negative
Reinforcement
Response
Consequence
Loud Noise
Press Lever
Loud Noise
Removed
Press Lever
Loud Noise
Applied
Punishment
No Noise
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Types of Punishment
Positive punishment –
The application or presentation of an aversive
stimulus after a response
Negative punishment –
The removal of an attractive stimulus after a
response
Both attempt to decrease the likelihood
that a behavior will reoccur
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Four Kinds of Consequences
GOAL
STIMULUS
Increase
Behavior
Decrease
Behavior
Positive
(Add)
Negative
(Subtract)
Positive
Reinforcement
Negative
Reinforcement
Bonus for working hard Aspirin relieving headache
leads to more hard work leads to more aspirin use
Positive
Punishment
Positive
Punishment
Getting speeding ticket
leads to less speeding
Missing dinner leads to
less staying out late
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The Use of Punishment
Punishment can result in immediate
change in behavior, often making it an
easy solution; should be a logical
consequence to make it work
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The Abuse of Punishment
Problems associated with punishment:
• Power of use usually disappears when threat
of punishment is removed
• Rewards can override/overpower the
punishment
• Often triggers escape or aggression
• Teaches legitimate use of aggression to
influence others
• May inhibit learning new and better responses
• Is often applied unequally
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When does punishment work?
• when presented without delay
• when consistent
• when limited in duration and intensity
• when consequence is logical
• limited to the specific situation at hand
• when no mixed messages are sent
• when negative punishment is used
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A checklist for Modifying Operant Behavior
Consider combining the following:
Positive reinforcement
-encourage desirable behaviors
Punishment
-use logical consequences, swiftly, without
undue harm
Negative reinforcement
Extinction
-control all possible reinforcers
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Inset table to illustrate comparison of
Classical and Operant Conditioning (pg.
3-40)
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Operant and Classical Conditioning
Compared
Classical conditioning involves the
association of two stimuli (UCS + CS)
before the response or behavior
Operant conditioning involves a reinforcing
(reward) or punishing stimulus after a
response or behavior
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How Does
Cognitive Psychology
Explain Learning?
According to cognitive
psychology, some forms of
learning must be explained
as changes in mental
processes, rather than as
changes in behavior alone
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How Does
Cognitive Psychology
Explain Learning?
Insight learning –
Problem solving occurs by suddenly
perceiving new forms or relationships
Cognitive maps –
A mental image used to navigate
through a familiar environment
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How Does
Cognitive Psychology
Explain Learning?
Latent learningwhen learning occurs without
reinforcement and without any hint that
learning took place
cognitive explanation of learning
vs. the behavioral explanation
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Observational Learning: Bandura’s
Challenge to Behaviorism
Observational learning (social learning)–
•
form of cognitive learning
•
new responses are acquired after
watching others’ behavior and
consequences of their behavior
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Rethinking Behavioral Learning in
Cognitive Terms
Cognitive-behavioral psychologists
• associations occur when the organism is
seen as an information seeker using
logical and perceptual relations among
events
• reinforcement changes expectations for
future rewards or punishments
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Brain Mechanisms and Learning
Long-term potentiation –
• Biological process involving physical
changes that strengthen the synapses in
groups of nerve cells
• believed to be the neural basis of
learning
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Brain Mechanisms and Learning
Extinction• forgetting unimportant associations
• neurotransmitters block memories
• glutamate; norephinephrine
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Brain Mechanisms and Learning
Learning circuitry• Simpler circuits
• Classical conditioning and operant learning
• Complex learning• Concept formation, insight learning, and
observational learning
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Brain Mechanisms and Learning
Observational learning and mirror neurons
• Neurons that help us imitate others’
behaviors
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