Forgetting 1. Memory Internal record or representation of past experience Not necessarily the same...
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Chapter 11 Forgetting 1
Forgetting 1. Memory Internal record or representation of past experience Not necessarily the same as the original experience History & metaphors Slate
Memory Internal record or representation of past experience Not
necessarily the same as the original experience History &
metaphors Slate Filing cabinet Computer 2
Slide 3
Types of Memory Many different types of memory 2 are important
for our purposes: Working memory: short-term, no need to store each
instance for future reference e.g. matching to sample: need to
remember what the sample was only until you make the choice Samples
change from trial to trial Reference memory: long-term, remember
specific information for future reference e.g. maze training:
remember lay-out of the maze, doesnt change across trials 3
Slide 4
Working Memory 4 Sample: Retention Interval: Choice: Remember
green Trial #1 Remember red Trial #2 Remember red Trial #3
Slide 5
Reference Memory 5 Start Food Trial #1 Trial #3 FoodStart Trial
#2 Start Food Goal is always in the same place remember over
time!
Slide 6
Behaviorist View of Memory No need to discuss representation No
focus on storage & retrieval Experiences ability to change an
organisms behaviour under certain conditions Stimulus control
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Slide 7
Forgetting Deterioration in learned behaviour following a
period without practice Defined behaviourally Performance vs
Description Note: extinction is not the same as forgetting 7
Slide 8
Measuring Forgetting Working memory Sample (training) Retention
interval (usually short seconds/minutes/hours) Test Next sample is
different Reference memory Training Retention interval (can be much
longer days/weeks) Test Samples (training) are always the same
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Slide 9
Free Recall Method Train, wait, test See how much deterioration
in performance All-or-nothing test of behaviour May not be
appropriate for complex tasks Some elements remembered, others not
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Prompted (Cued) Recall Give prompts to increase likelihood of
behaviour Two ways: Measure deterioration (same as free recall)
prompts help with complex tasks where free recall task might lead
to very low scores Measure number of prompts needed to produce
behaviour 11
Relearning Method Reinstall original training procedure after
retention period How many trials (or time) needed compared to
original training to return to initial level of proficiency?
Reacquisition 13
Slide 14
Relearning Learn : Banana Interesting Annoy Book Computer Trial
#1 Score = 2/5 Recall: Banana __________ Annoy __________ Recall:
Banana __________ Annoy Book __________ Trial #2 Score = 3/5
Recall: Banana Interesting Annoy Book Computer Trial #3 Score =
5/5Total Trials on Initial Learning = 3 How many trials to relearn
after a break (retention interval)? Difference = amount of
forgetting
Slide 15
Recognition Method Subject only has to identify material
previously learned E.g., distinguish between original stimulus and
a number of distracter stimuli 15
Slide 16
Recognition Which words were on the list? Banana Orange
Interesting Annoy Ugly Computer Table Apple 16 Learn: Banana
Interesting Annoy Book Computer
Slide 17
Delayed Matching to Sample Show S+ Wait (Delay = Retention
Interval) Choose from S+ and S- Working memory only Sample Delay
Matching 17
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Extinction Method Train two subjects (groups of subjects) Put
both on extinction, but one has delay between training and
extinction and the other doesnt Compare rate of extinction for two
subjects 18
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Extinction methods 19 Group 1 & 2 Learning Phase Group 1
Extinction break Group 2 Extinction Compare amount of time
Slide 20
Gradient Degradation Method Establish stimulus control
(discrimination training) Measure generalization gradient Repeated
measure gen. grad. over time If generalization gradient flattens,
forgetting 20
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Gradient degradation 21 Training: Establish gradient No
Forgetting Forgetting
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Is time a variable? Retention interval = Time between learning
and testing Greater the interval, less retained (i.e., more
forgetting) But, time is not an event (time doesnt account for
forgetting) Need causal factors 23
Overlearning Learn to asymptote, then keep training Learning
list perfectly, then practice a few more times Better recall for
longer Point of diminishing return Not a linear relationship
between overlearning and retention i.e. 100% overlearning isnt
twice as good as 50% overlearning 25
Slide 26
Krueger (1929) Adults learn 3 lists of 12 one-syllable nouns
List 1: go through list until they remember all 12 List 2: learn
list perfectly, then go through again for half as many trials as it
took to learn i.e. if they took 10 trials to learn perfectly, they
go through list another 5 times Group 3: learn list perfectly, then
go through again as many times as it took to learn i.e. another 10
times Relearn after various intervals 26
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Results Greater amount of overlearning, less forgetting 100%
overlearning better than 50% overlearning 50% overlearning way
better than 0% overlearning i.e. difference between 100% & 50%
was LESS THAN difference between 50% & 0% 27
Slide 28
Facilitation of Prior Learning Previous experience makes
something easier to remember Meaningful material easier to retain
than random material e.g. Easier to learn a complete sentence than
12 random words Prior experience important in determining what is
meaningful (e.g., words in known or unknown language) 28
Slide 29
DeGroot (1966) Arranged chess pieces on board as if in the
middle of a game Chess masters and novices; 5 seconds to observe
Masters reproduced arrangement 90% of time, novices only 40% Is
this prior experience, or do chess masters forget less than other
people? 29
Slide 30
Chase & Simon (1973) Chess pieces placed randomly on board
Masters no better than novices at recall Past learning of legal
arrangements is what increased masters performance in deGroot
(1966) study 30
Slide 31
Interference of Prior Learning Proactive interference Previous
learning interferes with recall of newer learning 31
Slide 32
Studying proactive interference Paired Associate Learning (PAL)
technique Subjects learn paired lists, tested with 1 item and must
recall second All learn A-C list, but some previously learned A-B
list In testing, give A and ask to recall C Those with A-B learning
have more difficulty recalling C when given A 32
Slide 33
PAL example 1 group first learns: Red-Apple Cloud-Shoe
Cat-Shelf Plate-Spoon Carpet-Tent Both groups then learn: Red-Book
Cloud-Paper Cat-Fence Plate-Notebook Carpet-Window 33 Both groups
then RECALL: Red- ________ Cloud- ________ Cat- ________ Plate-
________ Carpet- ________
Slide 34
Levine & Murphy (1943) Proactive interference with
attitudes Determine initial attitude towards communism Likert Scale
Read pro- and anti-communism passages Students who had prior
pro-communist attitudes forgot anti-communist elements of passages
but remembered pro-elements (and vice versa) Proactive interference
because attitudes are not innate; effect of prior learning 34
Slide 35
Subsequent Learning (Interference) Inactivity during retention
interval leads to less forgetting than activity Implies forgetting
partly based on learning new material Jenkins & Dallenbach
(1924) Recall (%) 100 50 Hours after learning tested 0 2 4 6 8
sleep awake 35
Slide 36
Retroactive Interference New learning interferes with ability
to recall earlier learning PAL technique (opposite order) Subjects
learn A-C, but some then learn A-B Test by giving A and recalling C
Subjects who learned A-B have worse recall for C e.g. forgetting
old phone numbers, license plates, passwords 36
Slide 37
PAL example BOTH groups first learn: Red-Apple Cloud-Shoe
Cat-Shelf Plate-Spoon Carpet-Tent 1 group then learns: Red-Book
Cloud-Paper Cat-Fence Plate-Notebook Carpet-Window 37 Both groups
then RECALL: Red- ________ Cloud- ________ Cat- ________ Plate-
________ Carpet- ________ Order is just switched from last
example
Slide 38
Context Learning occurs in a context Various stimuli around the
learner These stimuli serve as cues to evoke a behaviour If stimuli
absent, may have cue-dependent forgetting Stimulus control e.g.
forgetting names when in a different context 38
Slide 39
Context 39 SDSD Colour, size, shape, etc Cue set, set of S D s,
has changed! Less cues to signal correct response.
Slide 40
Perkins & Weyant (1958) Train two groups of rats in two
mazes, one black, one white 1 minute retention interval Half of
each group tested in original maze, half in maze of opposite colour
Opposite colour rats did poorly compared to original maze tested
rats 40
Slide 41
Kamin (1957) Gave rats avoidance learning, tested at various
retention intervals. Time of day, internal clock Internal
physiological state cues recall internal context Avoidance (%)
Retention Interval (hr) 0 12 24 36 48 60 72 84 100 50 41
Slide 42
State-Dependent Learning Train under a particular physiological
state (e.g., drug condition) and test under various states Recall
best when in the same state as training Drug conditions: alcohol,
caffeine, etc. Internal State: tired, level of stress, emotions,
etc. 42
Slide 43
Application: Foraging Food Caching Cache: food store Retrieval
of food later Spatial memory Wide variety of species Accuracy can
be quite high for very long times 43
Slide 44
Application: Eyewitness Testimony Notoriously poor Basic issue
of retention interval and forgetting Also the nature of the
question used to retrieve information 44
Slide 45
Loftus & Zanni (1975) Subjects watched film of car accident
Asked Did you see / broken headlight? the subjects twice as likely
as a subjects to say yes Actually, no broken headlight shown
Reinforcement history Previous conditioning: the (definite article)
implies presence; a implies possible presence 45
Slide 46
Loftus & Palmer (1974) Watch film of car accident How fast
were the cars going when they hit each other? Underlined word
replaced with smashed, collided, bumped, contacted Speed estimates
varied based on wording of question Reports of broken glass varied
based on wording 46
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Learning to Remember In essence, improving learning Practice
increases retention Techniques: Overlearning Mnemonics Context cues
Prompts 48
Slide 49
Overlearning Practice beyond learning e.g. Tiger Woods putting
practice e.g. Flash Cards (SAFMEDS) 49
Slide 50
Mnemonics Rhymes, First Letters HOMES, Roy G. Biv Method of
Loci Associate learned items with locations on a well-known route
Peg Word System 1 = bun, 2 = shoe, 3 = tree Also works with visual
1 looks like a pencil, 2 looks like a swan, 3 is a tricycle 50
Slide 51
Mnemonic example 1 coffee cup imagine using a coffee cup as a
pencil holder 2 rubber ball imagine a swan holding a rubber ball in
its beak 3 printer imagine a printer printing a piece of paper with
a tricycle on it 4 yoga mat imagine trying to balance in yoga
positions while on top of a table (4 legs) Etc. The more bizarre
the image, the easier it is to remember (lack of interference)
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Slide 52
Context Cues Keep context the same Study in classroom Pay
attention to habits, internal states 52
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Prompts Creating S+s Memos, notes, calendar markings Often dont
contain all info, so just a reminder of what needs to be done E.g.
3-Choice meeting String on finger, watch beep, cell phone reminders
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