Download classical conditioning

Chapter 6:
Learning
How Nurture Changes Us
Copyright © Allyn & Bacon 2009
Lecture Preview
Discuss classical conditioning and how
complex behaviors can arise from it
 Distinguish classical from operant
conditioning, and the principles of
reinforcement
 Explore the basis of observational and
insight learning
 Discuss biological influences on learning
 Evaluate learning fads
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True or False?
Once you reach adulthood, the brain is
basically fixed and does not change.
False. Recent evidence suggests that new
neurons grow even in the adult brain, especially
areas of the brain involved in learning.
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Basic Terminology
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Learning - change in an organism’s behavior
or thought as a result of experience
Habituation - process by which we respond
less strongly over time to repeated stimuli
Sensitization - process by which we respond
more strongly over time (especially for
dangerous, irritating stimuli)
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Eric Kandel earned the Nobel prize for his studies
of habituation and sensitization in Aplysia (the sea
slug)
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Classical Conditioning
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Ivan Pavlov - studied digestion in dogs,
noted associative conditioning between
neutral stimuli and meat powder
(Pavlovian conditioning)
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Classical Conditioning
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Pavlov described classical conditioning, involving:
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UCS unconditioned stimulus - biologically significant stimulus that
produces automatic response
UCR unconditioned response - automatic response to a UCS that
occurs without learning
CS conditioned stimulus - initially neutral stimulus, becomes
associated with the UCS through conditioning
CR conditioned response - learned response
By virtue of CS-UCS pairing, the CS comes to elicit the
CR, a response closely related, but not identical, to the UR
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Pavlov’s Classical Conditioning Model
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Classical Conditioning
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Where do we see
classical
conditioning used
everyday?
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Can you see how
classical
conditioning can
explain how we
learn prejudice?
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Classical Conditioning
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Aversive conditioning - classical
conditioning to an unpleasant UCS
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Avoidance response
Classical conditioning is adaptive in
preparing the organism for the impending
US
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Psychopathic personalities - indifferent to
signals of threat
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Classical Conditioning
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Acquisition - learning phase during
which a CR is established
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Extinction - gradual decrease and
elimination of the CR when the CS is
presented repeatedly without the UCS
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Classical Conditioning
Spontaneous recovery - sudden
reemergence of an extinguished CR after
a delay
 Renewal effect - tendency of an
extinguished CR to return when revisiting
the original conditioning environment
 Phobias - intense and irrational fears
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Some acquired via classical conditioning
 Subject to spontaneous recovery and
renewal
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Classical Conditioning
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Stimulus generalization - elicitation of a
CR to stimuli that are highly similar to, but
not identical to, the CS
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Generalization gradient - the more similar to
the original CS the new CS is, the stronger
will be the CR
Stimulus discrimination - opposite of
stimulus generalization; occurs when we
exhibit a CR to certain CSs, but not others
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Applications of Classical
Conditioning to Daily Life
1) Advertising - pairing positive USs with
product CSs
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Latent inhibition - when we’ve experienced
a CS alone many times, it’s difficult to
classically condition it to another stimulus
(e.g., highly known vs. novel brands)
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Applications of Classical
Conditioning to Daily Life
2) Acquisition of fears: Little Albert
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Watson & Reyner (1920) sought to disprove the
Freudian view of phobia, reflecting deep-seated
unconscious conflict
They recruited an infant, Albert, and paired a white
rat (CS) with a loud clanging metal noise (UCS)
Five days later, Albert exhibited fear of the rat, and
similar stimuli, including a rabbit, dog, furry coat,
and Santa Claus mask (generalization of phobia)
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Applications of Classical Conditioning
to Daily Life: Little Albert
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Led to the conditioning model of phobias
Classical conditioning also offers a way to
get rid of phobia
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Mary Clover Jones (1924) successfully treated
three-year-old Peter, who had a phobia of
rabbits, by slowly introducing a rabbit paired with
candies
Similar exposure therapy is still
the main behavioral treatment
for irrational fears
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Applications of Classical
Conditioning to Daily Life
3) Disgust reactions - in most cases, a product
of classical conditioning because CSs associated
with disgusting UCSs come to elicit disgust
themselves
 Rozin (1986) subjects show a great reluctance to
eat a piece of fudge shaped like dog feces
 Subjects show a great reluctance to drink a
sucrose solution labeled poison, even when they
put the meaningless label on there (“better safe
than sorry” heuristic)
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Operant Conditioning
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Or instrumental conditioning - acquiring
behaviors as a result of the outcome or
consequence of those behaviors
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The organism gets something out of the
response or “operates” on its environment
(e.g., using biscuits as a treat, a trainer
teaches a dog to sit)
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Differences Between Operant and
Classical Conditioning
Classical
Response Elicited by UCS or CS
Reward
Independent of what
the animal does
Body
System
Often involves
autonomic nervous
system
Operant
Organism emits
response in
a seemingly
voluntary fashion
Organism must make
response
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Often involves the
skeletal muscles
Law of Effect
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E. L. Thorndike (1898) studied cats in puzzle boxes,
which led to the law of effect:
If a response, in the presence of a stimulus, is followed
by a satisfying state of affairs, the bond between
stimulus and response will be strengthened
 According to Thorndike and others, learning involves
an association between a stimulus and response (SR), with the reward stamping in this connection
• Lack of insight in cats
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Thorndike’s Puzzle Box
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B. F. Skinner and Reinforcement
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Skinner developed a highly efficient
conditioning chamber (Skinner box)
that allows for conditioning and
automated behavior measurement
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Typically contains bar that delivers food
when pressed, food dispenser, and light
that signals when reward is forthcoming
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Rat in Skinner Box and Electronic Device
for Recording the Rat’s Behavior
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Terminology in Operant
Conditioning
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Positive reinforcement - pleasant stimulus is given
to increase the probability of a response
(e.g., cell phone for good grades)
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Negative reinforcement - unpleasant stimulus is
removed to increase the probability of a response
(e.g., Aidan’s mother’s nagging stops when he picks up his
room)
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Punishment - unpleasant stimulus is given, or
pleasant stimulus is taken away, to decrease the
probability of a response (e.g., cell phone taken away for
breaking curfew)
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Punishment tends to be ineffective
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It tells the organism what not to do, rather
than what to do
Creates anxiety that can interfere with future
learning
Encourages subversive behavior
(sneakiness)
Provides a model for aggressive behavior
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Physical punishment is associated with
aggression in adulthood: but what about the
role of genetics?
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Principles of
Reinforcement
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Partial reinforcement - behaviors that we reinforce
only occasionally are slower to extinguish than those we
reinforce continuously
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Schedules of reinforcement - pattern of reinforcing
a behavior
 Fixed Ratio - after regular number of responses
 Variable Ratio - after specific number of responses, on
average
 Fixed Interval - after specific amount of time
 Variable Interval - after an average time interval
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Applications of Operant
Conditioning
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Shaping by successive reinforcement reinforcing behaviors that aren’t quite the target
behavior but that are progressively closer
versions of it
Chaining - linking a number of interrelated
behaviors to form a longer series
Premack principle - a less frequently performed
behavior can be increased by reinforcing it with a
more frequent behavior
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Grandma’s rule - vegetables before dessert
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Applications of Operant
Conditioning
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Superstitious behavior - behavior linked to
reinforcement by sheer coincidence (e.g., lucky charm
effect)
Prejudice- how is it developed through operant
conditioning?
Token economies - mental hospital staff can reinforce
patients who behave in a desired fashion using tokens,
chips, points, or other secondary reinforcers
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Secondary reinforcers - neutral objects that patients can later
trade in for…
Primary reinforcers - items or outcomes that are naturally
pleasurable, such as a favorite food or drink
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Applied Behavioral Analysis (ABA)
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ABA - a set of techniques, pioneered by Ivar
Lovaas at UCLA, and based on operant
conditioning principles, that relies on the careful
measurement of behavior before and after
implementing interventions
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Shaping techniques with primary reinforcers
Children with autism treated with ABA show
significant progress in language and intellectual
skills
Before Lovaas, many of these children would
have been institutionalized
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Two-Process Theory: Putting Classical
and Operant Conditioning Together
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Classical and operant conditioning are distinct in
many ways, including underlying brain systems, but
how they interact is called two-process theory
 People acquire phobias via classical conditioning,
then avoid their feared stimulus
(e.g., avoiding dogs after dog bite)
 This avoidance produces negative reinforcement,
via anxiety reduction, maintaining the phobic
response
 So phobias may involve classically conditioned
fear AND operant avoidance
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Apply Your Thinking
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Sarah is afraid of flying. She prides
herself on not taking any pills. What are
some ways she may be able to enjoy
flying more?
Exposure therapy and extinction
 Positive reinforcement
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Other Forms of Learning
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Latent learning - learning that isn’t
directly observable; we learn many
things without showing them
Emphasizes the difference between
competence (what we know) and
performance (showing what we know)
 Challenge to radical behaviorism,
implies reinforcement isn’t necessary
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Other Forms of Learning
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Observational learning - learning by
watching others (models), without
instruction or reinforcement
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Brain basis? Perhaps mirror neurons
Aggressive behavior: Bandura (1963) had
children watch an adult ignoring or punching a
Bobo doll and shouting things like “Kick him”
Children who watched the aggressive adult
model were aggressive to the Bobo doll later
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Media Violence Leads to
Real-World Aggression?
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Scores of investigators have proposed that
violent TV programs promote aggressiveness in
children
Correlation or causation?
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Longitudinal designs
Laboratory experiments
Field studies (e.g., examining aggression in a town with no
TV)
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From these studies - media violence contributes
to aggression in some circumstances
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Longitudinal Study of Individuals Who
Watched Violent TV as Children
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Apply Your Thinking
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A school teacher is having trouble with Audrey hitting
her classmates. He notifies the father, who spanks
Audrey. The next day Audrey hits another classmate.
When an adult angrily approaches her, she cowers in
fear. What happened and what should the teacher do?
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Audrey demonstrated observational
learning/modeling.
Audrey shows classical conditioning of fear.
The father should be taught that modeling good
behavior and using reinforcement-based strategies
will be more effective than punishment.
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Other Forms of Learning
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Kohler (1925) studied apes solving
problems, in one case, reaching bananas
by putting together two sticks that were not
long enough individually
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Seemed evidence for “Aha!” phenomenon
Insight learning - when subjects suddenly
“get” the solution to a problem, and from
there on get it right almost every time
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Biological Influences
on Learning
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Preparedness regarding phobias suggests that
we’re evolutionarily predisposed to fear certain
stimuli more than others
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Monkeys are predisposed to become afraid of things such
as toy snakes and alligators, but not toy flowers or rabbits
About half of dog phobics have never had direct negative
experience with a dog
Classical conditioning does not account for all phobias
Tendency for animals to return to innate behaviors
following repeated reinforcement: instinctive drift
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Breland’s “coin washing” raccoons
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Learning Fads:
Do They Work?
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Sleep-assisted learning - listening to audio tapes while
you sleep
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Learn Morse code quicker?
Better controlled studies suggested that the tapes awoke
the subjects, they were not really asleep
Accelerated learning - SALTT
Discovery learning - giving students experimental materials
and asking them to figure out scientific principles on their own
 Klahr (2004) - 3rd, 4th graders asked to figure out variables
affecting how quickly a ball rolls down a ramp
• Only 23% learned the principles using discovery learning, but
77% did with direct instruction
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Learning Styles:
Fact or Fictional Fad?
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Do all individuals have their own
distinctive learning styles?
Analytical or spatial or verbal learners?
 Findings not reliable
 Studies show tailoring learning methods to a
particular style doesn’t result in enhanced
learning
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Most of us use a mixture of styles
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Apply Your Thinking
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One treatment for alcoholism is a drug (pill)
called Antabuse® – it makes you very sick when
you drink alcohol. Should this treatment work?
Based on the principles we’ve discussed, why
or why not?
Yes, via conditioned taste aversion
 No, avoidance and noncompliance
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