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Operant Conditioning
Pavlovianlearning how stimuli provide informationabout other stimuli
Operantlearning how your behavior leads to goodand bad results
Natural selection effective organisms survive other ones die out results in complex well adapted organisms
Behavioral selection behavior leading to good outcomes
is strengthened other behavior dies out results in complex behavior that is
suitable for the environment
The Law of Effect(voluntary responses, not reflexes)
Responses followed by good thingsare strengthened
Responses followed by bad thingsare weakened
R Re responses (reward or reinforcer)
GoodConsequence
Bad Consequence
Behaviorproducesconsequences
Behavioreliminatesconsequences
Positivereinforcement
Omission
Punishment
NegativeReinforcement
The Law of Effect(voluntary responses, not reflexes)
Responses followed by good thingsare strengthened
Responses followed by bad thingsare weakened
R Re responses (reward or reinforcer)
GoodConsequence
Bad Consequence
Behaviorproducesconsequences
Behavioreliminatesconsequences
Positivereinforcement
Omission
Punishment
NegativeReinforcement
Increaseprobabilityof response
The Law of Effect(voluntary responses, not reflexes)
Responses followed by good thingsare strengthened
Responses followed by bad thingsare weakened
R Re responses (reward or reinforcer)
GoodConsequence
Bad Consequence
Behaviorproducesconsequences
Behavioreliminatesconsequences
Positivereinforcement
Omission
Punishment
NegativeReinforcement
Decreaseprobabilityof response
bar
pre
ss r
ate
acquisition
time
extinction
ratoutofbox
spontaneousrecovery
stopreinforcement
Operant conditioning may also be subjectto inhibition.
Contingency vs. Contiguity
Does the response have to predict the consequence?
Hammond (1980)
nofood food
positive
press bar 5 95 contingency
Rat learns
don’t press 0 100 to press!
nofood food
zero
press bar 5 95 contingency
Rat stops
don’t press 5 95 pressing or doesn’t learn
Supports Contingency
Conditioned Reinforcement
Skinner (1938)
Phase 1“click” . . . . . food
conditioned primaryreinforcer reinforcer
Phase 2Rats learn to press a bar to hearthe “click”
Other examples praisemoneygrades
Conditioned reinforcers only develop when theypredict primary reinforcer(more evidence for contingency)
Token Reinforcers
First train animals that tokens can be
exchanged for food
(e.g., vending machine)
Then see if animals will learn other responses
to get tokens
Chimpanzees
•tokens work as well as “real” reinforcers
•fight over the tokens
panel
Learned Helplessness (Seligman)
Phase I - Learning to Escape
Control Dogs Yoked Dogs
Shock
•A long lasting shock is given to both groups
every once in a while
•Control dogs can turn shock off by pushing a
panel
•Yoked dogs’ shock turns off too, when control
dog pushes panel
•Yoked dogs can do nothing themselves to escape
shock
Phase 2 - Avoidance Learning
•shock delivered to one side of box•if dog jumps hurdle to other side there is no shock
Control dogs learn to avoid shockYoked dogs don’t
Yoked dogs have learned that they can’t stop shockThey have learned to be helpless
hurdle
“Curing” learned helplessness
Curing learned helplessness requires the animal toexperience success
Depression is like learned helplessness
•passive•lose weight•have trouble learning new tasks
•Drag the dog over the hurdle a few times•Eventually learns to avoid shock
Preventing Learned Helplessness
If dogs are first exposed to shock that they can
turn off and then exposed to uncontrollable
shock, they don’t learn to be helpless.
Early Experience!
Methods for Studying Memory
STUDY TEST retention interval
Recall Tests
Free recall
Serial recall
Cued recall
steel thread
tights universe
cob batteries
eye cow
pear clarinet
nail pitch
airplane mittens
bunny sprinkler
spaghetti saucer
canary microphone
Recognition
DRUM
CORD Study
KITE
PARROT
yes-no Test
CLASS
KITE
CORD CORN Forced
Choice
KITE BIRD
HIT MISS
FALSEALARM
CORRECTREJECTION
OLD
ITEM
NEW
RESPONSE“YES” “NO”
Experiments with no study phase
Autobiographical Memory
•Recall all of your elementary school teachers
•Where were you when “Challenger” spaceshuttle blew up?
How do you know if recall is accurate?
Semantic Memory
Tests of general knowledge
Easy questions“Is an oak a tree?”measure response time
Hard questionsWhich is bigger, an eagle or a raccoon?
Savings in Relearning
Learn Relearnsomething the same thing
How many If it takestrials? few trials, you
have memory
% savings =
trials for trials fororiginal learning relearning
trials for original learning
Examplelearning ancient Greek passages
STUDY - 1-1/2 year old has Greek passages readto him
TEST - Age 8
TEST
10 new passages 30 trials
10 old passages 21 trials
% savings = = 30%
Conclude:
There is some memory for old passages
30-2130
“Classic” or Standard Theory of Memory
Selectivity of Encoding
Only some information is storedpermanently
ABCDEFGHIJKL
C DE ]FG
H
E
Rejects
conveyor
For closer examination
not good
enough
Hi-grade
Rejects
conveyor
For closer examination
not good
enough
Hi-grade
Information from sense organs
Sensory Memory
AttentionSystem
Short-Term Store
Forgotten
LongTermStore
Classic Theory
SensoryMemories
IconicStore
EchoicStore
Attention Filter
Short-TermStore
Long-TermStore
•large capacity•rapid turnover•“raw” information
•small capacity•symbolic information
•almost unlimitedcapacity
eyes ears
Short-Term Store
some metaphors
1. Box with Slots
(limitedcapacity)
2. A work bench
wherethinkingtakes place
parrot pizza jet
parrot jet
3. STS is the activated part of long-term store
4. STS is your consciousness
jetparrotpizza
parrot jetheli-
copter pizzaham-
burger
birdfly
plane food
eats
What is in STS?
Mental Symbols
sound of the word “dog”appearance of the letter “A”
world
STS LTSperception
retrieval from LTS
What happens to items in STS?
LTS
SensoryMemory
STS
forgottenif not
rehearsed
rehearsalkeeps item
in STS
transferredto LTS ifrehearsed
a lot or ifimportant
What do symbols inSTS stand for?
(Coding)
Classic Theory
words & letters are coded by sound(acoustic)
ORinternal articulationnot by meaning
Conrad (1964)serial recall of letters
confusions are acoustic
code must be acoustic
F D K Y X C M
right rite wright right write rite
B C P V E C T
How is STS Limited?
1. Number HypothesisSTS can hold only a fixed numberof symbols
7 2 (Miller)
2. Time HypothesisAny symbol in STS will be lost inaround 2 seconds if it is notreactivated by rehearsal
Span of STS is determined by decay rate (2 sec)and the rate of rehearsal
Baddeley, Thomson & Buchanan (1975)
tested memory span for words
memory span = number of items where immediate serial recall is perfect
short words “pig” “bet”long words “noon “rose” (take longer
to say toyourself)
Memory span was greater for short words
Conclude:Your memory span is the number of wordsyou can rehearse in 2 seconds
The Time Hypothesis is correct
Improving STS Capacity
1. Chunking with recoding
combine many symbols into one
T H E D O G
“the dog”
0 0 1 0 1 0 1 1 1
1 2 7
2. Chunking without recoding
organize symbols into groups
7 1 6 - 2 7 5 - 7 2 6 1
Are STS and LTS Really Different?
Classic Theory says “yes”!
time
capacity
cause offorgetting
nature ofsymbols(coding
STS
a fewseconds
a fewitems
decay or“gettingbumped
out”
acoustic/articulatoryfor words
LTS
“permanently”
“unlimited”
retrievalfailure
anything
Immediate Free-Recall Serial Position Curve
100%
recall
1 2 3 25
primacy
asymptote
recency
| | |
serial position
Immediate Free-Recall Serial Position Curve
100%
recall
1 2 3 25
primacy
asymptote
recency
| | |
serial position
nonrecencyLTS
STS
Dissociations in free recall serial position curve
1. No dissociation
Condition A iseasier than Bover all positions
2. A is better thanB for nonrecencyonly
A is better for LTS
3. A is better than Bfor recency only
A is better for STS
Recall A
B
A
B
A
B
Actual DissociationsSupporting STS-LTS Distinction
Independentvariable
presentationrate
SLOW vs. FAST
intervening taskbefore recall
orno task
old-age vs.college-age
subjects
amnesicvs.
normalsubjects
Effect onRecency
SLOW =FAST
NO TASK >TASK
YOUNG ≈OLD
AMNESIC ≥NORMAL
Effect onNonrecency
SLOW > FAST
NO TASK = TASK
YOUNG > OLD
AMNESIC = 0
Immediate Free-Recall Serial Position Curve
100%
recall
1 2 3 25
primacy
asymptote
recency
| | |
serial position
Immediate Free-Recall Serial Position Curve
100%
recall
1 2 3 25
primacy
asymptote
recency
| | |
serial position
Craik (1970)
Recency items are recalled worse than nonrecencyitems in final free recall
Supports STS-LTS distinction
NegativeRecencyEffect
FINAL FREE RECALL
Effects of Marijuana on Memory
Darley et al. (1973)
start •presentation and immediate free recall often lists
•administration of drug or placebo
after one hour -Phase 1 Final free recall of ten lists
Recall .4 -.2 -
serial position
Phase 2 Presentation and immediate free recall of ten new lists
Recall .8 -.6 -.4 -.2 -
serial position
Conclude: Drug hurts transfer from STS to LTS
No differenceDrug doesn’teffect retrievalfrom LTS
Drug isworse onnonrecencyonly
placebo
drug
drug
placebo
Problems with Classic Theory
(1) You can get recency even when STS isn’tinvolved
•Baddeley & Hitch (1977) “Rugby” experiment
•Roediger & Crowder (1976) “President”experiment
100%
serial position of presidents
Washington Lincoln Ford
Nixon
Recency
(2) The Classic Theory’s view of rehearsal is wrong
Craik & Watkins (1973)
Phase 1
keep track of most recent “b” word
“basket” “spoon” “telephone” “baby”
report “baby”
Rehearsal time
basket - 2 items
Phase 2
recall all “b” words
%recall
| | | | | | |0 1 2 3 4 5 6
Rehearsal Time
20—
10 —Actual Data
(2) The Classic Theory’s view of rehearsal is wrong
Craik & Watkins (1973)
Phase 1
keep track of most recent “b” word
“basket” “spoon” “telephone” “baby”
report “baby”
Rehearsal time
basket - 2 items
Phase 2
recall all “b” words
%recall
| | | | | | |0 1 2 3 4 5 6
Rehearsal Time
20—
10 —Actual Data
(sheer amount of rehearsal doesn’t matter always)
If classic theoryis right
Levels of ProcessingTheory of Memory
A modification of the Classic Theory
Craik & Lockhart (1972)
•memory is determined by encoding
•the “deeper” the processing during encoding, thebetter the memory
•amount of rehearsal is not important
•distinction between STS (primary memory) andLTS (secondary memory) is still present
Craik & Lockhart (1972)
2. Kinds of rehearsal
maintenance - keep repeating word
at shallow (phonemic) level
KEEPS WORD AVAILABLE, but DOES NOT improve long-term memory for word
elaborative - think about the meaning of the word in lots of different ways
(semantic)
does improve long-term memory
Relation Between Rehearsal and Perception
What happens when you perceive a word?
D O G
Stage 1 detect parts of letters(visual)
recognize letters “D” “O” “G”
Stage 2 convert letters to “phonemes”(phonemic)
D = d O = o G = hard g
Stage 3 convert phonemes to meaning(semantic)
“d o g” = pet that barks
Event:
D O G
letters(visual)
sound(phonemic)
meaning(semantic)
concentrateon letters
poormemory
concentrateon sound
fairlyshort
memory
concentrateon meaning
longlasting
memory
shallow
deep
1. Personally significant? 2. 2 syllables? 3. Animate? 4. Personally significant? 5. 2 syllables? 6. Animate? 7. Personally significant? 8. 2 syllables? 9. Animate?10. Personally significant?11. 2 syllables?12. Animate?13. Personally significant?14. 2 syllables?15. Animate?16. Personally significant?17. 2 syllables?18. Animate?19. Personally significant?20. 2 syllables?21. Animate?
Watkins & Watkins, 1974
Supports the idea that negative recency in finalrecall is due to shallow processing when list length is known (maintenance rehearsal)
listlengthknown
listlength
unknown
serial position
immediate recall
final recall
Support for Levels of Processing
Craik & Tulving (1975)
Orienting questions
Case word in capital letters
TABLEsubject responds yes
Rhyme word rhymes with weight?
MARKETsubject responds no
Sentence word fits in sentence
“He met a _______”
FRIENDsubject responds yes
Probabilityof “Hit” inRecognition
.8
.6
.4
.2
sentence rhyme case
Deeper means better memory
“yes” better than “no” (elaboration)
yes
yes
yesno
no
no
Some Criticisms
1. Theory fails to emphasize retrieval cues.
2. Theory fails to say exactly what is “deeper”processing
Fisher & Craik (1977)Shows that retrieval cues are as important as depth of processing during encoding.
STUDY
TEST
context - itempail - HAILmilk - COWmat - CAT
leaf - TREE
pail? (HAIL)dog? (CAT)
milk? (COW)free? (TREE)
rhyme contextsemantic contextrhyme contextsemantic context
cue encodingsame cue - rhymesemantic - rhymesame cue - semanticrhyme - semantic