psy 368 human memory
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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) - PowerPoint PPT PresentationTRANSCRIPT
PSY 368 Human Memory
Memory Forgetting cont. &Recognition
• 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)
How do we forget?
• 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?
• Dog – Book• Tree - Cloud• Shoe - Car• Pen - Soda• Clip - Horn• Leaf - Cup• Truck - Ant• Fish - Goat• Lake - Peach
• Recall from first list• Dog – ?• Tree - ?• Shoe - ?• Pen - ?• Clip - ?• Leaf - ?• Truck - ?• Fish - ?• Lake - ?
• Dog – Bed• Tree - Cake• Shoe - Couch• Pen - Stool• Clip - House• Leaf - Chair• Truck - Apple• Fish - Gas• Lake - Penny
How do we forget?
• Dog – Book• Tree - Cloud• Shoe - Car• Pen - Soda• Clip - Horn• Leaf - Cup• Truck - Ant• Fish - Goat• Lake - Peach
• Recall from first list• Dog – ?• Tree - ?• Shoe - ?• Pen - ?• Clip - ?• Leaf - ?• Truck - ?• Fish - ?• Lake - ?
• Dog – Bed• Tree - Cake• Shoe - Couch• Pen - Stool• Clip - House• Leaf - Chair• Truck - Apple• Fish - Gas• Lake - Penny
Introducing a related second list of items impairs recall of the first list.
Introducing a related second list of items impairs recall of the first list.
• Proactive Interference (PI)
How do we forget?
• 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.
On a separate sheet of paper: Write down all the words from the 2nd list- on back side - you
remember
Turn the paper over and study the list of words on the back page, one at a time, for 1 min.
How do we forget?
• List 1• Tulip• Daisy• Hydrangea• Orchid• Violet• Magnolia• Carnation• Rose• Lilac
• List 2a• Dandelion • Pansy• Iris• Gardenia• Daffodil• Lily• Peony• Geranium• Marigold
• List 2b• Cheetah• Horse• Skunk• Llama• Mouse• Raccoon• Lemur• Rabbit• Monkey
• Rose…tulips….• Rose....horse…• Same total number or
items learned
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
(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
Forgetting Summary
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 age-group?
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 Implicit tests• Intentional retrieval
• Free recall
• Recognition
• Unintentional retrieval
• use memory w/o knowing it
• Lexical Decision
• Stem Completion
Recall vs Recognition
• List the names of the seven dwarves
GrouchyGabbyFearfulSleepySmileyJumpyHopefulShy
Droopy
DopeySniffyWishfulPuffyDumpySneezyLazyPop
Grumpy
BashfulCheerful
TeachShortyNiftyHappyDocWheezyP-
Diddy
Recall vs Recognition
• Y/N this is one of the seven dwarves
• 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
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)
• 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
How does Recognition work?
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)
Eagle & Leiter (1964)
• Learning types (Intentional vs. Incidental)
Single Process Models
• 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
Kinsbourne & George (1974)
• Word frequency effects
Single Process Models
• 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
• 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)
Dual-process theories
• Study list• Dandelion • Pansy• Iris• Gardenia• Daffodil• Lily• Peony• Geranium• Marigold
• “Recall the list”
(1) Generate set of candidates• Pansy• Lily• Carnation• Daffodil• Dandelion • Tulip• Rose• Daisy
(2) Recognition Check if worthy
OKOK
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)
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
Dual-process theories
• Recall failure is quite common and explainable, but recognition failure is contrary to the prediction of generate-recognize 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
Problem with G-R theory
Recognition FailureWatkins & Tulving (1975)
• Demonstrated that a word could be recalled, even though it could not be recognized
Step Procedure Example
1a1b
List 1 presentedCued recall of List 1
badge-buttonbadge- ? (button)
2a2b
List 2 presentedCued recall of List 2
preach-rantpreach- ? (rant)
3 List 3 presented glue-chair
4a4b
Free association stimuli presentedFree association responses made
tabletable-chair, cloth, desk, dinner
5a5b
Recognition test sheets presentedRecognized items circled
desk top chairdesk top chair
6 Cued recall of List 3 glue- ? (chair)
Traditional paired associate learningCritical list
not tested immediately
Strong associate of probe in List 3Forced choice recognition
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
(Tulving , 1985; Gardiner, 1988)
Relatively recent change in recognition methodologyDoes 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”
Remember versus Know Process Model
Dual-process theories
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 Process Model
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)
• 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
Dual-process theories
• R/K differ by:• Picture superiority
effect• R: P > W• K: W > P
• Generation effect• R: G > R• K: R = G
• Word frequency effect• R: L > H• K: H = L
• 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• Studies done by Fantz (1961, 1963) - had kids look at three kinds of
figures
• Johnson and Morton (1991) report that new-born babies will preferentially view faces
Face Recognition
• 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.
• Evidence for special ability:(3) Face inversion effect
• 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)
Face Recognition
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?
• Evidence for special ability:(4) Pop-out effect for faces (Herschler & Hochstein,
2005)
Face Recognition
Now find the animal face. Ready?
Face Recognition
(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
Summary
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
Yes No
Test ItemOld Hit Miss
New False Alarm Correct Rejection
52
The ‘Thatcher Illusion’
(Thomson, 1980)
53
The ‘Thatcher Illusion’
(Thomson, 1980)
54
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.