Transcript 13-14 Learning 021806-handout

Learning I and II
• Chemotherapy patient has anticipatory nausea, so
cannot keep up her strength. How does this
happen and what can be done to help it?
• Dealing with parent/children problems: Child acts
up at a store. Parent ignores, then responds by
yelling and grabbing child. What are
consequences and how might it be handled?
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Learning Unit
Overview of Class
(I) Definition of learning
(II) Biological constraints on learning
(III) Varieties of learning
(A) Habituation
(B) Classical conditioning
(C) Instrumental conditioning
(D) Classical & Instrumental conditioning
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(I) Definition of Learning
Learning - storage of information in memory as a
consequence of experience
* Learning is inferred from performance
* But . . . . Learning is not equivalent to performance
** Fatigue, Motivation, Specific performance measures
Challenge of learning -- what goes with what?
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(II) Biological Constraints on Learning
(A) Fixed action patterns - innate behaviors
(B) Critical periods
(C) Stimulus/response specificity
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(II) Biological Constraints on Learning
(A) Fixed action patterns - innate behaviors
Characteristics:
* Initiated by specific stimuli
* Progress automatically once initiated
Examples:
* Grasping, sucking & head turning, respiration
occlusion reflex
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(II) Biological Constraints on Learning
(A) Fixed action patterns - innate behaviors
(B) Critical periods
* Imprinting - basis for child/parent attachment
* Bird song, Language learning
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Figure 6-2 Apparatus used for the imprinting of ducklings. A duckling was given
Systematic exposure to the decoy as it moved around the runway.
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In a choice discrimination test, percent of time that ducklings chose
the imprinted decoy as a function of time between birth and the
imprinting experience.
Age (hours)
Hess, E. H. Imprinting. Science, 1959, 130, 133-141.
Reprinted by permission of the American Association
for the Advancement of Science.
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(C) Stimulus/Response Specificity
Early view; All stimuli have an equal chance of being
associated with responses
Present view: Some S-R pairs have precedence in learning
Intervention
Shock
Nausea/X-rays
Bright/noisy water
Training
Sweet water
HIGH
low
low
HIGH
Conclusions: External punishment -- > external stimulus
Internal punishment -- > internal stimulus
Example: Odors & tastes associated with chemotherapy
are strong cues for anticipatory vomiting
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Evidence that the consequences of responding determine the stimuli that come to
control the response.
X-ray
Shock
Revusky, S., & Garcia, J. Learned associations over long delays. In G. H. Bower (Ed.),
The psychology of learning and motivation (Vol. 4). New York:
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Academic Press,1970, pp. 1-84. Reprinted by permission of Academic Press, Inc.
(III) Varieties of Learning
(A) Habituation - decreased responding to repetitive stimulus
* From single cell organism to human ………………..
* Example: Finch study
** Alternative explanations for “habituation”:
(a) Fatigue - No - “dishabituation”
Response returns if stimulus changes a little
(b) Extinction of conditioned response ….. No
Response will come back with delay
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Relative Frequency of Calls (percent)
Decline in “chink” calls emitted by chaffinches on successive
daily tests with a live owl. Each chaffinch was exposed to
the owl for 20 min. a day. The number of calls emitted by
each day was expressed as a percentage of the number on Day 1.
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Daily Tests
(B) Classical Conditioning
Pavlov and his famous dogs ……………………..
Critical observation: Dog salivates when Pavlov enters room
Experiment:
Before conditioning
UCS
Meat powder
UCR
Salivation
CS
Buzzer
Orienting
Response
During conditioning
CS ….. UCS
UCR
After conditioning
CS
Buzzer
CR
Salivation
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(a) Does the temporal relationship between the CS & UCS matter?
Forward
CS
UCS
Best
Delayed
CS
UCS
Learning
Backward
CS
UCS
Worst
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(b) Is conditioning permanent?
Assumes:
CS without UCS after conditioning
* Process of Extinction
* Process of Spontaneous Recovery
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(c) Is conditioning automatic & unselective?
Animal “A” - tone conditioned
Conditioning
UCS
Shock
CS
Tone
UCR
Fear
Orienting
Test
CS
Tone
CR
Fear
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Animal “B” - tone and light conditioned
Conditioning
UCS
Shock
CS
Tone & Light
UCR
Fear
Orienting
Test
CS
Tone
CR
Fear
CS
Light
CR
Fear
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Animal “C” - tone, then tone & light -- Blocking
Initial Conditioning
UCS
Shock
CS
Tone
UCR
Fear
Orienting
Then with same animal… second conditioning phase.
UCS
Shock
CS
Tone & Light
UCR
Fear
Orienting
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Animal “C” - what has the animal learned?
Test -- tone still conditioned to fear, but light is NOT Initial conditioning of tone has BLOCKED it from
being learned in second conditioning phase
CS
Tone
CR
Fear
CS
Light
Orienting
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(d) Does CR become equivalent to UCR?
Early view: (Pavlov) - Yes
Recent view:
CR takes whatever form is most adaptive
--- can be compensatory or opponent to UCR
An Example: Drug tolerance …… and overdose
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An Example: Drug tolerance …… and overdose
UCS
Heroin
UCR
Decreased
respiration
Drug has UCR but also a rebound
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Opponent Process Theory
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Predicted Effects of Conditioning on Opponent Processes
• As can see in
Panel B, as
conditioning
continues, the
opponent
process b (CR)
increases in size
and counteracts
the UR, a
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An Example: Drug tolerance …… and overdose
UCS
Heroin
CS
Familiar
environment
UCR
Decreased
respiration
CR
Increased
respiration
*Drug has UCR (component a) and then rebound of increased respiration
(component b -- withdrawl)
*Component b malleable, gets conditioned to familiar environment, and
occurs earlier so counteracting UCR.
*Need higher dose to get same effect
BUT ….. When in an unfamiliar environment there is no counteracting27
effect and therefore possible overdose
Overdosing
• Two groups of mice injected with ethanol
for four days in same environment
• Day 5 - given 1.5 times usual dose
– Familiar environment -- 0% fatalities
– New environment -- 60% fatalities
• Newer findings (Siegel, 2004)-- may also be
true of internal cues to drugs
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(e) Real-world effects & applications of Classical Learning
* Phobia - unrealistic fear which develops from a frightening
experience (claustrophobia)
* Anxiety
* Situational Hypertension
* Systematic Desensitization - method for reducing intense anxiety
by having patients visualize a
graduated series of anxietyprovoking stimuli while
maintaining a relaxation
CS
CR
Aircraft, airport, etc.
Anxiety
???????
extinction or new (calmer) response
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Here are the first fifteen scenes from a hierarchy used with a client
who feared flying.
1. You are reading the paper and notice an ad for an airline.
2. You are watching a television program that shows a groups of people boarding
a plane.
3. Your boss tells you that you need to make a business trip by air.
4. It is two weeks before your trip, and you ask your secretary to make airline
reservations.
5. You are in your bedroom, packing a suitcase for your trip.
6. You are in the shower on the morning of your trip.
7. You are in a tax on the way to the airport.
8. You are checking in for your flight and the agent says, “Would you like a
window or aisle seat?
9. You are in the waiting lounge and hear an announcement that your flight is
now ready for boarding.
10. You are in line, just about to board the airplane.
11. You are in your seat and hear the plane’s engines start.
12. The plane begins to move as you hear the flight attendant say, “Be sure your
seatbelts are securely fastened.”
13. You look at the runway as the plan waits to take off.
14. You look out the window as the plane begins to roll down the runway. 30
15. You look out the window as the plane leaves the ground.
Chemotherapy and classical conditioning
• Become associated with tastes and odors
• Foods eaten before therapy may lead to
taste-aversion, a problem for nutrition
• Distinctive food before chemotherapy can
be “scapegoat” so aversion tied to that.
– Children given unusual candy (coconut-flavor)
with meal before therapy
– Other foods in meal more likely to be eaten
later than for group with no unusual candy
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Final remark on classical conditioning
• Many organisms show classical
conditioning
• Neural bases are very different, but form is
very similar
• Why? Adaptive way of responding
– To survive, we have systems to anticipate and
react to common, important stimuli
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Instrumental (operant) Conditioning
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(C) Instrumental (Operant) Conditioning
Operant Behavior
Reinforcer
Child eats vegetables
“Barney” video
(a) Shaping - reinforcing approximations of desired
behavior
* dramatically speeds-up conditioning (especially)
when behavior occurs infrequently
(b)Superstitious behavior
Operant behaviors
carry rabbit’s foot
consult palm reader
Reinforcer
desired outcome
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(C) Instrumental (Operant) Conditioning
(c) Schedules of Reinforcement
* Fixed ratio - each n responses
- paid for each piece --> fast responses
* Variable ratio - each variable # responses
- slot machines --> hard to extinguish
* Fixed interval - after t time
-emergency room admissions in N.Y.
--> scalloped curve
* Variable interval - after variable time
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- unannounced examinations --> hard to extinguish
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Partial reinforcement
• Harder to condition behavior (since many
unreinforced desired actions)
• Longer to extinguish behavior (since
extinction not so different from learning -many unreinforced desired actions)
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(d) Types of Behavior-Reinforcer Contingencies
* Positive reinforcer - something positive following behavior
* Negative reinforcer- removal of something aversive
** escape conditioning
* Punishment - administration of something aversive
Disadvantages: ** doesn’t tell you what to do
** elicits aggression & hostility
To be effective:
immediate, severe, consistent, offer alternative behaviors
Learned helplessness (Seligman) - organism punished in an
unpredictable manner will show impaired learning
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Learned helplessness
Group A
Phase 1: Shock -- escaped by pressing nose pad
Phase 2: Shock -- escaped by jumping over
barrier
Group B
Phase 1: Shock -- same as Group A - no control
over escaping (pressing nose pad did not help)
Phase 2: Shock -- could escape by jumping over
barrier, but do not -- learned helplessness
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Learned helplessness repairing
Some evidence that if can show organism that
behavior WILL influence environment, that
they can get over learned helplessness.
If animals forced over barrier repeatedly, will
begin to jump over it to avoid shocks.
Real-world applications
Math anxieties; clinical depressions
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What is reinforcement reinforcing?
• Learning or Performance?
• Evidence is Performance -- important to
realize that organisms (people) can be
learning much more than they are showing
by performance
– Example: Rats -- cognitive maps of routes
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(e) Applications of Instrumental Conditioning
* Programmed instruction - small units of
behavior are reinforced. Gradually increase unit
size.
* Behavior Modification
** Smoking cessation programs
** Weight loss programs
** Token economies in psychiatric hospitals
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(D) Classical & Instrumental Learning
Have examined separately, but
1. Many similarities in effects of practice, extinction, recovery,
blocking -- classical between stimulus and stimulus, instrumental
between stimulus and response (leading to reinforcer)
2. often there are mixtures of Classical & Instrumental learning
Classical conditioning - anticipatory vomiting with chemotherapy
CS / medical office
CR / vomiting
IF ….. patient is distracted from CS vomiting should cease
Instrumental conditioning
Operant behavior
imagery/relaxation
Reinforcer
Decreased vomiting
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Concluding remarks
• Wide variety of very different events arise
from conditioning
• Be aware that behaviors you see may come
about in unintended ways -- useful when
you are considering how to repair harmful
behaviors
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Readings and key terms
Fadem - Ch. 7
• Fixed action patterns
imprinting
• Classical conditioning
• Systematic desensitization
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•
•
•
Habituation Critical periods,
Extinction UCR, CR, UCS, CS
Spontaneous recovery
Operant conditioning
Shaping
Partial reinforcement
Fixed ratio, variable ratio, fixed interval, variable interval
Positive and negative reinforcers Punishment
Learned helplessness
Behavior modification
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