Transcript PSY 368 Human Memory - the Department of Psychology at Illinois

PSY 368 Human
Memory
Memory Forgetting cont. &
Recognition
How do we forget?
• Theories of forgetting:
• Failure of Consolidation
• Failure of retrieval
• Decay
• Context/cue mismatch
• Interference
How do we forget?
• Interference (McGeoch, 1932)
• Info encoded before or after can interfere
• Storing similar memories impedes retrieval.
• Over time, many similar experiences occur, especially since
people are creatures of habit.
• Two types:
• Retroactive = info that comes AFTER interferes
• Proactive = info that comes BEFORE interferes
How do we forget?
• Retroactive Interference (RI)
• Forgetting caused by encoding new traces into memory in
between the initial encoding of the target and when it is tested.
• Introducing a related second list of items impairs recall of the first
list compared to a control condition.
How do we forget?
• Recall from first list
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Dog – Book
Tree - Cloud
Shoe - Car
Pen - Soda
Clip - Horn
Leaf - Cup
Truck - Ant
Fish - Goat
Lake - Peach
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Dog – Bed
Tree - Cake
Shoe - Couch
Pen - Stool
Clip - House
Leaf - Chair
Truck - Apple
Fish - Gas
Lake - Penny
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Dog – ?
Tree - ?
Shoe - ?
Pen - ?
Clip - ?
Leaf - ?
Truck - ?
Fish - ?
Lake - ?
How do we forget?
Introducing a related second list of items
impairs recall of the first list.
• Recall from first list
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Dog – Book
Tree - Cloud
Shoe - Car
Pen - Soda
Clip - Horn
Leaf - Cup
Truck - Ant
Fish - Goat
Lake - Peach
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Dog – Bed
Tree - Cake
Shoe - Couch
Pen - Stool
Clip - House
Leaf - Chair
Truck - Apple
Fish - Gas
Lake - Penny
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Dog – ?
Tree - ?
Shoe - ?
Pen - ?
Clip - ?
Leaf - ?
Truck - ?
Fish - ?
Lake - ?
How do we forget?
• Proactive Interference (PI)
• The tendency for older memories to interfere with the retrieval of
more recent experiences and knowledge.
• The number of previous learning experiences (e.g. lists) largely
determines the rate of forgetting at long delays.
Demo
Study the list of words on the front page (see the
highlighted 1), one at a time, for 1 min.
Turn the paper over and study the list of words on the
back page, one at a time, for 1 min.
On a separate sheet of paper: Write down all the words
from the 2nd list- on back side - you remember
How do we forget?
• List 1
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Tulip
Daisy
Hydrangea
Orchid
Violet
Magnolia
Carnation
Rose
Lilac
• List 2a
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Dandelion
Pansy
Iris
Gardenia
Daffodil
Lily
Peony
Geranium
Marigold
• List 2b
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Cheetah
Horse
Skunk
Llama
Mouse
Raccoon
Lemur
Rabbit
Monkey
How do we forget?
• Release from PI (2nd list doesn’t interfere as much)
• Change in item type can release interference
• Learn 2 lists of flowers vs. 1 of flowers and 1 of animals
• Rose…tulips….
• Rose....horse…
• Same total number or
items learned
Recal of
1st
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All flowers
Flowers & Animals
Lists learned
Forgetting Summary
(1) Tend to remember faces, languages, some skills for
very long time – permastore
(2) Forgetting due to decay and/or interference
(retroactive, proactive) and/or lack of consolidation
Questions to Think About
• Does the type of memory test matter?
• Which test is easier – a recognition test or a recall
test? (What makes one test easier than another?)
• Why is it easier to recognize faces of one’s own agegroup?
Questions to Think About
• Does the type of memory test matter?
• Yes, but the language used to describe the different tasks
is messy
• Here is how I’ll try to use the vocabulary
• Incidental subject doesn’t know about future memory test
• Intentional subject does know about future memory test
• Implicit memory: memory without awareness, involves
unintentional influence of memory
• Explicit memory: memory with awareness, involves intentional
retrieval
Memory Task Types
Explicit tests
• Intentional retrieval
• Free recall
• Recognition
Implicit tests
• Unintentional retrieval
• use memory w/o
knowing it
• Lexical Decision
• Stem Completion
Recall vs Recognition
• List the names of the
seven dwarves
Recall vs Recognition
• Y/N this is one of
the seven dwarves
Grouchy
Gabby
Fearful
Sleepy
Smiley
Jumpy
Hopeful
Shy
Droopy
Dopey
Sniffy
Wishful
Puffy
Dumpy
Sneezy
Lazy
Pop
Grumpy
Bashful
Cheerful
Teach
Shorty
Nifty
Happy
Doc
Wheezy
P-Diddy
Recall vs Recognition
• Definitions
• Hollingworth (1913)
• In a recall test, the experimenter provides the context and the
subject has to retrieve the target; in a recognition test, the
experimenter provides the target and the subject has to retrieve
the context.
• Recall – must generate the response
• Recognition
• Alternative Forced Choice (2AFC, 4AFC)
• Given multiple choices, choose the one already seen
• Yes-No
• Given one choice, indicate whether the item is “old” or “new”
Recall vs Recognition
Shepard (1967)
• Subjects presented with lists of stimuli
• Words, sentences, photographs
• Recognition Test
• At test, presented with two stimuli, one from original list,
one new (similar to the old one)
• Words: 88%
• Sentences: 89%
• Pictures: almost 100%
• 1 week later, still at 87% for pictures
Recall vs Recognition
Mäntylä (1986)
• Subjects presented with lists of words, for which they
had to generate three properties for each
• Recall experiment
• At test, experimenter presented the properties
• Subjects recalled approximately 91% of the words at an
immediate test
• Performance dropped off over time
• 1 day 78%, 2 days 71%, 7 days 60%
• So with the appropriate cues, recall can be very good too
• (best the more self-generated properties they made)
How does Recognition work?
• Two classes of theories
• Single process theories - retrieval is one process
regardless of task
• Dual process theories - two processes needed for
retrieval - can be task dependent
Single Process Models
• Early theories of recognition
• Tagging Model (Yntema & Trask, 1963)
• When an item occurs, it is tagged with the relative time of
occurrence, during retrieval look for items with “tags”
• Explains why you can say which item came first
• Strength Theory (Wickelgren & Norman, 1966)
• Items vary in strength
- Studied items increase strength (as a function of recency)
Single Process Models
• Early theories of recognition
• Limitations
• These models contain only a single process
• Predict same results for recognition and recall
• Meaning that the same manipulation (word frequency,
intentionality, etc) should have the same effect on both recall
and recognition)
Single Process Models
Eagle & Leiter (1964)
• Learning types (Intentional vs. Incidental)
• Task:
• Intentional (INT)
• Hear words, will recall
later
• Incidental (INC)
• Hear words, is it a Noun
or Verb?
• Recall and Recognition
• Results
• Recall: INT > INC
• Recognition: INT < INC
Single Process Models
Kinsbourne & George (1974)
• Word frequency effects
• Task:
• study high or low
frequency words
• (e.g., tree - high freq. vs.
arboretum - low freq.)
• Tests:
• Recall and Recognition
• Results:
• Recall: high > low
• Recognition: low > high
Dual-process theories
• Generate-recognize model (G-R)
• E.g., Anderson & Bower (1972), Kintsch (1970)
• Remember/Know processes model (R/K)
Dual-process theories
Generate-recognize model (G-R)
• Recall is made up of two processes
• First, generate a set of plausible candidates for recall (Generation
stage)
• Second, confirm whether each word is worthy of being recalled
(Recognition stage – not the same as the recognition test)
• Recognition is made up of only one process
• Because the experimenter provides a candidate, recognition does
not need the generation stage
Dual-process theories
Generate-recognize model (G-R)
• Study list
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Dandelion
Pansy
Iris
Gardenia
Daffodil
Lily
Peony
Geranium
Marigold
• “Recall the list”
(1) Generate set of
candidates
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Pansy
Lily
Carnation
Daffodil
Dandelion
Tulip
Rose
Daisy
(2) Recognition Check
if worthy
OK
OK
nope
• Recall needs steps 1 & 2
• Recognition only needs
step 2 (since 1 it is done
for you)
Dual-process theories
Generate-recognize model (G-R)
• Example: Human Associative Memory (HAM)
• Anderson and Bower (1973)
• Assumes words are stored in associative network
• At encoding
• As words are presented, they are tagged with a contextual marker
• Pathways to associated words are also tagged
• At recall:
• Contextual markers are followed to generate a set of plausible
candidates (Generation stage)
• After examining number of associations between target word and
context, “old” or “new” is chosen depending on sufficient
contextual evidence (Recognition stage)
Dual-process theories
Generate-recognize model (G-R)
• Solves limitations of single process model
• The same manipulation does not have to have the same effect on
both recall and recognition
• This model does a better job of explaining learning type and word
frequency effects
• Incidental learning means fewer inter-item associations (no reason to form
associations if don’t know about upcoming test)
• Hurts generation & helps recognition
• High frequency items are easier to generate, but they are also more likely to
have appeared in other contexts, so recognition is harder
• Helps generation & hurts recognition
Problem with G-R theory
• Recall failure is quite common and explainable, but
recognition failure is contrary to the prediction of generaterecognize models
• Recalled words should also be recognized
• Because the second stage is common to both recall and
recognition, a successful outcome in one test should mean a
successful outcome for the other
• Watkins and Tulving (1975) tested this prediction
Recognition Failure
Watkins & Tulving (1975)
• Demonstrated that a word could be recalled, even
though it could not be recognized
Traditional paired
associate learning
Critical list
not tested immediately
Step
Procedure
Example
1a
1b
List 1 presented
Cued recall of List 1
badge-button
badge- ? (button)
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2b
List 2 presented
Cued recall of List 2
preach-rant
preach- ? (rant)
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List 3 presented
glue-chair
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Free association stimuli presented
Free association responses made
table
table-chair, cloth, desk, dinner
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Recognition test sheets presented
Recognized items circled
desk top chair
desk top chair
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Cued recall of List 3
glue- ? (chair)
Strong associate of probe 4b
in List 3
Forced choice recognition 5a
49% of recalled items (step 6) not recognized (step 5)
Generate-Recognize Models
• Adding a search process during recognition stage
could allow a generate-recognize model to account
for recognition failure
• Familiarity instantly computed to make response (automatic
and fast process, based on ease of processing)
• If familiarity value is not decisive enough, a search is
performed (a slower process)
• In the previous experiment, the target word (chair) is not “found”
in the search because the retrieval phase (step 5) contained
inappropriate cues
• The recall test (step 6) provided appropriate cues, so the search
process is successful
Dual-process theories
 Remember versus Know Process Model
(Tulving , 1985; Gardiner, 1988)
Relatively recent change in recognition methodology
Does someone
 Specifically remember
 Conscious recollection of the information’s occurrence at study
 Just somehow know
 Knowing that it was on the list, but not having the conscious
recollection, just a “feeling of knowing”
Dual-process theories
 Remember versus Know Process Model
 Tulving (1985)
 Present subjects with category-member pairs (PET– cat)
 Recall tests:
 Free recall test
 Cued recall test (category) PET
 Cued recall test (category + first letter of target) PET - c
 The proportion of remember judgments decreased over
the three kinds of tests
Remember Versus Know
 Gardiner (1990, 1993) gives an explanation:
 Remember judgments are influenced by conceptual and
attentional factors
 Know judgments are based on a procedural memory system
 Like explicit and implicit memory (more on this next week)
 Data from remember/know experiments support the
idea that recognition is a combination of two processes
 Recollection (remember judgments) and
 Familiarity (know judgments)
Dual-process theories
• Remember/Know processes
• Make R/K judgment for “Old” items
• Remember = consciously recollect details of the item’s
presentation
• Know = sure an item was presented, but can’t recall any of the
details of presentation
• R/K differ by:
• Picture superiority
effect
• R: P > W
• K: W > P
• Word frequency
effect
• R: L > H
• K: H = L
• Generation
effect
• R: G > R
• K: R = G
Face Recognition
• Special recognition ability
Face Recognition
• Evidence for special ability:
(1) Prosopagnosia
• The inability to recognize previously seen faces, with relative
sparing of other perceptual, cognitive and memory functions.
• Intact ability to identify people using nonfacial features (voice)
• Due to brain injury (typically to the right temporal lobe)
• Broad Subtypes:
1. Apperceptive - failure to generate a sufficiently accurate percept to allow
a successful match to stores of previously seen faces.
2. Associative - accurate percept, but failure to match because of loss of
facial memory stores or disconnection from them.
Face Recognition
• Evidence for special ability:
(2) Newborn preferences
Looking Time (secs)
• Studies done by Fantz (1961, 1963) - had kids look
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at three kinds of figures
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Face
Mixed Face
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Age (months)
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• Johnson and Morton (1991) report that new-born
babies will preferentially view faces
Face Recognition
• Evidence for special ability:
(3) Face inversion effect
• Yin (1969) found that whilst
people are generally better at
recognising upright faces than
they are other objects. They
are worse for inverted faces
than they are for other
inverted objects.
• This suggests that the processing underlying normal face recognition
is different from those underlying object recognition.
Face Recognition
• Evidence for special ability:
(4) Pop-out effect for faces (Herschler & Hochstein, 2005)
Find the human face in the display as fast as you can. Ready?
Face Recognition
Find the human face in the display as fast as you can. Ready?
Face Recognition
• Evidence for special ability:
(4) Pop-out effect for faces (Herschler & Hochstein, 2005)
Now find the animal face. Ready?
Face Recognition
Summary
(1) Recognition is an explicit memory test.
(2) Single- and dual-process theories of recognition
(3) Single-process can’t account for differences
across recall and recognition
(4) G-R theory can’t account for recalled, but not
recognized items
(5) Face recognition seems to be a special ability
Summary
(1) Recognition is an explicit memory test.
(2) Single- and dual-process theories of
recognition
(3) Single-process can’t account for differences
across recall and recognition
(4) G-R theory can’t account for recalled, but
not recognized items
(5) Face recognition seems to be a special ability
The Mirror Effect
• Observed when “The type of stimulus that is
accurately recognized as old when old is also
accurately recognized as new when new. The type
that is poorly recognized as old when old is also
poorly recognized as new when new.” (Glanzer &
Adams, 1985, p.8)
• Pervasive in recognition tests
• High/low word frequency and hit/false alarm rates,
presentation rate, age of subject, ...
The Mirror Effect - Example
The Mirror Effect and the Word Frequency Effect
Word Frequency
High
Low
Hits
27.84
31.00
False Alarms
10.20
7.63
Source: Human Memory, p. 214
The Mirror Effect
• Significance: It eliminates all theories of recognition
based on a unidimensional conception of strength or
familiarity (single process models)
• May be able to be explained by dual process models
• Explanations for the mirror effect are still being
formed
Ethnicity effect (O’Toole et al., 1994)
• Face recognition better for same
ethnicity
Yes-No Recognition Test
Possible Outcomes in a Yes-No Recognition Test
Subject’s Response
Test Item
Yes
No
Old
Hit
Miss
New
False Alarm
Correct Rejection
The ‘Thatcher Illusion’
(Thomson,
1980)
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The ‘Thatcher Illusion’
(Thomson,
1980)
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Why does the ‘Thatcher
illusion’ occur?
• Bartlett and Searcy (1993) conducted experiments to
measure face ‘grotesqueness’.
• Their results supported the “configural processing
hypothesis”
• i.e. We have a difficulty in understanding the configuration of
features when faces are inverted.
• We aren’t aware of the odd configuration of elements within the
inverted Thatcher image.
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