Download Chapter 6

9/1/2009
Learning and Adaptation
Thomas Karlsson
Adapting to the Environment
 What is learning?
• Process by which
experience produces a
relatively enduring change
in behavior or capabilities
(knowing how)
6-2
Adapting to the Environment
 Environmental Shaping of
Behavior
• Personal adaptation (via
laws of learning)
• Species adaptation (via
evolution, natural selection)
6-3
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Adapting to the Environment
 Behaviorism
• Focused on how organisms
learn
• Discovered laws of learning
that apply to virtually all
organisms
6-4
Adapting to the Environment
 Behaviorism cont.
• Treated organism as tabula
rasa
• Explained learning solely in
terms of directly observable
events
6-5
Adapting to the Environment
 Ethology
• Focused on animal behavior in
natural environments
• Focused on functions of
behavior
6-6
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Adapting to the Environment
 Ethology
• Special focus on adaptive
significance of behavior: How
behavior influences chances of
survival, reproduction
• Different species learn
different behaviors to survive.
6-7
Adapting to the Environment
 Ethology
• Fixed Action Patterns
• Unlearned (innate) responses
• Can be modified by
experiences
6-8
Adapting to the Environment
 Cognitive Neuroscience
• Gestalt Psychology
• Cognitive Psychology
• Expertise
6-9
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Adapting to the Environment
 Habituation
• Decrease in response
strength to a repeated
stimulus
6-12
Forms of Learning
 Habituation
 Classical Conditioning
 Operant Conditioning
 Observational Learning
 Cognitive
Learning/anticipation
 Insight Learning
6-13
Classical Conditioning
 Learn to associate two stimuli
6-14
• One stimulus elicits a
response that was originally
elicited only by the other
stimulus
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Classical Conditioning
 Unconditioned stimulus
(UCS)
• Stimulus that elicits a
reflexive or innate response
(UCR) without prior learning
6-15
Classical Conditioning
 Unconditioned response
(UCR)
• Reflexive or innate
response elicited by the
UCS without prior learning
6-16
Classical Conditioning
 Conditioned stimulus (CS)
• Stimulus that, through
association with the UCS,
comes to elicit a
conditioned response
similar to the original UCR
6-17
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Classical Conditioning
 Conditioned response (CR)
• Response elicited by a
conditioned stimulus
6-18
Classical Conditioning
6-19
Classical Conditioning
 Acquisition
• Period during which CR is being
learned
6-20
• Types of CS-UCS pairing
 Forward short-delay
 Forward trace
 Simultaneous
 Backward
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Classical Conditioning
 Factors that Typically Enhance
Acquisition
• Multiple CS-UCS pairings
• An intense, aversive UCS can
produce one-trial learning
• Forward (short-delay) pairing
• Time interval between onset of CS
and onset of UCS is short
6-21
Classical Conditioning
 Extinction
• Process in which CS is
presented in absence of UCS
• Causes CR to weaken and
eventually disappear
6-22
Classical Conditioning
 Spontaneous Recovery
• After a rest period, and without any
new learning trials, the
reappearance of a previously
extinguished CR
• Usually weaker than initial CR,
extinguishes more rapidly
6-23
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6-24
Classical Conditioning
 Stimulus Generalization
• Stimuli similar to initial CS
elicit a CR
• Aids in survival
6-25
6-26
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Classical Conditioning
 Discrimination
• CR occurs to one stimulus
but not to another
6-27
Classical Conditioning
 Higher-order conditioning
• Neutral stimulus becomes a
CS after pairing with
already established CS
6-28
6-29
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6-30
6-31
Classical Conditioning
 Applications of Classical
Conditioning
• Conditioned fear responses
• Therapies for fear, anxiety
• Research
6-32
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Classical Conditioning
 Exposure Therapy
• Extinction of CR through
exposure to CS without
presence of UCS
6-33
Classical Conditioning
 Types of Therapy Using
Classical Conditioning
• Systematic desensitization:
Muscular relaxation paired with
gradual exposure to fear-inducing
stimulus
• Flooding
6-34
Classical Conditioning
 Other Influences of Classical
Conditioning
• Attraction to other people
• Positive, negative attitudes
• Conditioned aversions (aversion
therapy)
• Anticipatory nausea and vomiting (ANV)
• Allergic Reactions
6-35
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Classical Conditioning
 Aversion Therapy
• Condition an aversion
• Stimulus that triggers
unwanted behavior is paired
with a noxious UCS
6-36
Classical Conditioning
 Effects on Immune System
• Neutral stimuli can be
conditioned to increase or
decrease immune
functioning
6-37
• Procedure has been used to
help fight disease
6-38
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6-39
Operant Conditioning
 Instrumental Learning
(Thorndike, 1911)
• Organism’s behavior is
instrumental in bringing
about certain outcomes
6-40
Operant Conditioning
 Thorndike’s Law of Effect
• Response followed by a
“satisfying” consequence
becomes more likely to occur
• Response followed by an
“unsatisfying” consequence
becomes less likely to occur
6-41
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6-42
6-43
Operant Conditioning
 What is Operant
Conditioning?
• Behavior is influenced by
consequences that follow it
(Skinner, 1938, 1953)
6-44
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Operant Conditioning
 Reinforcement
• Response is strengthened
by outcome that follows it
 Punishment
• Response is weakened by
outcome that follows it
6-45
Operant Conditioning
 Skinner’s Analysis of Operant
Behavior
• A: antecedents of behavior
• B: behaviors
• C: consequences that
follow behavior
6-46
Operant Conditioning
 Skinner’s Analysis of Operant
Behavior
• IF A is present
• AND B is emitted
• THEN C will occur
6-47
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Operant Conditioning
 Differences Between Classical
and Operant Conditioning
• Classical: Behavior changes due
to association of two stimuli (CSUCS) presented prior to the
response (CR)
• Operant: Behavior changes as a
result of consequences that follow
it
6-48
Operant Conditioning
 Differences Between Classical
and Operant Conditioning cont.
• Classical: Focuses on elicited
behavior
• Operant: Focuses on emitted
behaviors
6-49
Operant Conditioning
 Discriminative Stimulus
• Signals that a particular
response will produce
certain consequences
6-50
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Operant Conditioning
 Positive Reinforcement
• Occurs when a response is
strengthened by the
presentation of a stimulus (the
positive reinforcer) that follows
it
6-51
Operant Conditioning
 Positive Reinforcement
• Primary reinforcers
• Stimuli that organism finds
reinforcing because they
satisfy biological needs (e.g.
food, drink)
6-52
Operant Conditioning
• Secondary reinforcers
• Acquire reinforcing
properties through
association with primary
reinforcers (e.g. money,
praise)
6-53
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Operant Conditioning
 Negative Reinforcement
• Response strengthened by
removal (or avoidance) of
an aversive stimulus (the
negative reinforcer)
6-54
Operant Conditioning
 Operant Extinction
• Weakening and eventual
disappearance of an operant
response
• Why?
• Response is no longer
reinforced
6-55
Operant Conditioning
 Operant Extinction cont.
• Resistance to extinction
influenced by pattern of
reinforcement that has
maintained behavior
• Good alternative to
punishment
6-56
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Operant Conditioning
 Aversive Punishment
• Response weakened by
subsequent stimulus
presentation
• E.g. spanking or scolding
6-57
Operant Conditioning
 Meta-analysis of Corporal
Punishment Studies (Gershoff,
2002)
• 88 studies; 36,000 participants
• Punishment is somewhat
effective in temporarily
suppressing misbehavior
6-58
Operant Conditioning
 Gershoff (2002) cont.
Punishment is associated with:
• Decreased parent-child quality
relationship
• Poorer internalization of moral
standards
• Increased aggressive behavior
during childhood and adulthood
6-59
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Operant Conditioning
 Gershoff (2002) cont.
Punishment is associated with:
6-60
• Increased childhood and
adulthood delinquent and
antisocial behavior
• Poorer childhood and adulthood
mental health
• Increased childhood risk of
physical abuse and becoming an
abuser as an adult
Operant Conditioning
1) Corporal
punishment
Aggression
Or?
2) Corporal
punishment
Aggression
6-61
Operant Conditioning
Or?
3) Corporal
punishment
Aggression
Third Variable
6-62
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Operant Conditioning
 Durrant (2000): After corporal
punishment ban in Sweden
• Decline in teenage theft, rape,
narcotics trafficking, use of
alcohol and other drugs,
suicide
6-63
Operant Conditioning
 Response Cost
• Response weakened by
subsequent removal of a stimulus
• Examples:
 loss of privileges or money
 misbehaving child gets “time
out” that removes opportunity
to watch TV or play
6-64
Operant Conditioning
 Effectiveness of Punishment
(Holden, 2002)
• Must occur after every
transgression
• Must be immediate
• Must be intense
• Must not be signaled by
discriminative stimulus
6-65
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Operant Conditioning
 Shaping
• Reinforce successive
approximations toward a
final response
6-66
Operant Conditioning
 Chaining
• Reinforce each response with
opportunity to perform next
response
• Develops a sequence of behaviors
• Usually begin with final response
in sequence and work back toward
first response
6-67
Operant Conditioning
 Operant Generalization
• Operant response occurs to
a new antecedent stimulus
or situation similar to the
original one
6-68
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Operant Conditioning
 Operant Discrimination
• Operant response occurs to
one antecedent stimulus
but not another
6-69
 Stimulus Control
• A discriminative stimulus
influences a behavior
Operant Conditioning
 Continuous Reinforcement
• Every response of a particular
type is reinforced
 Partial Reinforcement
• Only some responses are
reinforced
6-70
Operant Conditioning
 Types of Partial
Reinforcement Schedules
• Ratio:
Certain percentage of
responses are reinforced
6-71
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Operant Conditioning
 Types of Partial Reinforcement
Schedules
• Interval
Certain amount of time must
elapse between reinforcements
6-72
Operant Conditioning
 Types of Partial Reinforcement
Schedules
• Fixed
Reinforcement occurs after a
fixed number of responses or
fixed time interval
6-73
Operant Conditioning
• Types of Partial Reinforcement
Schedules
• Variable
Reinforcement occurs after
an average number of
responses or passage of
time
6-74
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Operant Conditioning
 Fixed Ratio Schedule (FR)
• Reinforcement given after a
fixed number of responses
 Variable Ratio Schedule (VR)
• Reinforcement given after a
variable number of responses,
centered around an average
6-75
Operant Conditioning
 Fixed Interval Schedule (FI)
• First correct response after a
fixed time interval is reinforced
6-76
 Variable Interval Schedule (VI)
• Reinforcement given for first
correct response after a
variable time interval, centered
around an average
6-77
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Operant Conditioning
 Continuous-Partial
Reinforcement Differences
 With continuous reinforcement:
• More rapid learning
• Consequences easier to
perceive
• Extinction more rapid
6-78
Operant Conditioning
 Escape Conditioning
• Learn responses to terminate
aversive stimuli
 Avoidance Conditioning
• Learn responses to avoid
aversive stimuli
6-79
6-80
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Operant Conditioning
 Two-Factor Theory of Avoidance
Learning (Mowrer, 1947;
Rescorla & Solomon, 1967)
• Both classical and operant
conditioning are involved
6-81
6-82
Operant Conditioning
 Applications: Education and
Workplace
• Teaching machines (Skinner) and
computer-assisted instruction
Immediate feedback
Self-paced learning
• Token economies: Desired
behavior reinforced with tokens,
exchangeable for rewards
6-83
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Operant Conditioning
 Applications: Specialized Animal
Training
• Animals assist people who have
disabilities
• Animals assist police, military
• Animals perform in entertainment
industry
6-84
Operant Conditioning
 Applications: Modifying Problem
Behaviors
• Applied Behavior Analysis
• Behavior modification
6-85
6-86
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Operant Conditioning
 Modifying Behavior
• Specify the problem
• Collect baseline data
• Identify antecedents (A) and
consequences (C)
• Develop plan to modify A, C
• Implement program and measure
progress
6-87
6-88
Crossroads of Conditioning
 Biological Constraints
• Preparedness (Seligman, 1970)
Animals are biologically
predisposed to learn some
associations more easily
than others
• Occurs through evolution
6-89
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Crossroads of Conditioning
 Conditioned taste aversions
• Organism becomes ill
(nausea, vomiting) after
eating a food
• The food (taste, sight, smell)
then becomes a CS that
triggers a CR of disgust,
repulsion
6-90
Crossroads of Conditioning
 Conditioned taste aversions
• Influenced by biological
preparedness
Sweet water readily becomes
a CS when paired with nausea
Lights, sounds are less likely
to become a CS when paired
with nausea
6-91
Crossroads of Conditioning
 Conditioned fear
• Influenced by biological
preparedness
Lights, sounds readily
become a CS when paired with
electric shock
Sweet water is less likely to
become a CS when paired with
electric shock
6-92
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Crossroads of Conditioning
 Evolution and Preparedness
• Biological preparedness for
fears among humans
• Using electric shock as UCS,
easier to condition fear to sight
of snakes and spiders than to
sight of flowers
6-93
Crossroads of Conditioning
 Biological Constraints on
Operant Conditioning
• Instinctive Drift
A conditioned operant
response “drifts back” toward
instinctive behavior
6-94
Crossroads of Conditioning
 Cognition and Conditioning
• Early behaviorist approach was
known as S-R (stimulus-response)
psychology
• Assumed relatively automatic
formation of bonds between
S and R
6-95
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Crossroads of Conditioning
 S-O-R (Cognitive) Model of
Learning
• O = organism’s cognitive
representation of the world
6-96
Crossroads of Conditioning
 Insight (Kohler, 1925)
• Sudden perception of useful
relationships that can solve
problems
• Challenged ideas about trialand-error learning
6-97
Crossroads of Conditioning
 Cognitive Maps (Tolman, 1948)
• Mental representations of spatial
layouts
• Suggests that learning provides
knowledge and expectation of
“what leads to what”
6-98
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Crossroads of Conditioning
 Cognition in Classical
Conditioning
• Expectancy Model (Rescorla &
Wagner, 1972)
CS produces an expectancy
that the UCS will follow
6-99
Crossroads of Conditioning
 Cognition in Operant
Conditioning
• Organisms develops an
awareness or expectancy of
response-consequence
contingencies
6-100
Crossroads of Conditioning
 Cognition in Operant
Conditioning
• Latent Learning
Learning that occurs at Time A but is
not demonstrated until Time B when
there is an incentive
6-101
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Crossroads of Conditioning
 Cognition in Operant
Conditioning
• Cognitive self-evaluations
Self-evaluations can serve as
reinforcers and punishers
6-102
Observational Learning
 What is observational
learning?
• Learning that occurs by
observing the behavior of a
model
6-103
Observational Learning
 Social-Cognitive Theory; also
known as Social Learning
Theory (Bandura, 1969, 2004)
• People learn by observing the
behavior of models AND
• by acquiring self-efficacy
6-104
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Observational Learning
 The Modeling Process (Bandura)
• Attention
• Retention
• Reproduction
• Motivation
6-105
Observational Learning
 Self-Efficacy
• a person’s belief that she or he
has the capability to perform
behaviors that will produce a
desired outcome
6-106
Observational Learning
 Impact of Social Cognitive
Theory
• Imitation of aggression and
prosocial behavior
• International development of
mass media projects to reduce
social problems (e.g., AIDs,
national illiteracy)
6-107
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