PSY 368 Human Memory

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


• 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”



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


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)


• 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)


• 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


• 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


Generate-recognize model (G-R)


• 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)


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


• 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


(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


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


• 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.

Documents

PSY 368 Human Memory