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

PSY 368 Human
Memory
Development of Memory
Development of Memory
infancy
childhood
adulthood
Our focus so far
This
Week
elderly
Development of Memory
• Outline for this week
• Studying infants & children
• Basic Processes and Capacities
• Methodological issues
• Memory in the Elderly
• What abilities decline?
• Why do they decline?
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Recognition and Recall
Implicit and Explicit memory
Episodic memory
Standard Model
• Sensory
• STM/WM
• LTM
Development of Memory
• Outline for this week
• Studying infants & children
• Basic Processes and Capacities
• Methodological issues
• Memory in the Elderly
• What abilities decline?
• Why do they decline?
• How do we test infants?
• Non-Nutritive Sucking
• Habituation/Dishabituation
• Conditioning
Development of Memory
• Outline for this week
• Studying infants & children
• Basic Processes and Capacities
• Methodological issues
• Memory in the Elderly
• What abilities decline?
• Why do they decline?
Will cover next time
Studying Infants
• Recognition Memory in infants
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Non-Nutritive Sucking
method (infants will adjust
sucking rate to get preferred
stimuli)
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DeCasper & Spence (1986)
Had mothers read stories
everyday to fetuses during final
6 weeks of pregnancy
After babies were born tested to
see if babies preferred familiar
story over novel one
Results: babies recognized and
preferred the familiar stories
(most-likely the prosody, of the
story)
Studying Fetuses
• Recognition Memory in the womb
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We experience language before we are even born
Fetal heart monitor
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DeCasper, et al (1994)
Studying Fetuses
• Recognition Memory in the womb
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We experience language before we are even born
Fetal heart monitor
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DeCasper, et al (1994)
Had mothers read rhymes everyday to
fetuses during 34-38 weeks of
pregnancy
After 38th week, two rhymes were
played to the fetuses (but mom
couldn’t hear it)
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Same rhyme
Different rhyme
Studying Fetuses
• Recognition Memory in the womb
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We experience language before we are even born
Fetal heart monitor
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DeCasper, et al (1994)
Had mothers read rhymes everyday to
fetuses during 34-38 weeks of
pregnancy
After 38th week, two rhymes were
played to the fetuses (but mom
couldn’t hear it)
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Same rhyme
Different rhyme
Studying Fetuses
• Recognition Memory in the womb
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We experience language before we are even born
Fetal heart monitor
DeCasper, et al (1994)
Had mothers read rhymes everyday to
fetuses during 34-38 weeks of
pregnancy
After 38th week, two rhymes were
played to the fetuses (but mom
couldn’t hear it)
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Decreased fetal
heart-rate
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Same rhyme
Different rhyme
Baby learned something about the
rhyme before it was born!
Studying Infants
• Recognition Memory in infants
• 2 weeks post-habituation: 2-month-olds prefer to look at a
novel scene or object
• Habituation technique
Studying Infants
• Habituation technique
Habituation/Dis-habituation:
Preference for novelty:
• familiarize with A
• familiarize with A
• then present A or B
• then present A and B together
• if infant dis-habituates to B, then
infant remembers A and can
discriminate between A and B
• if infant shows a preference for B,
then infant remembers A and
prefers B because it is a novel
stimulus
The basic idea is that if the infant prefers, or responds differently to the
novel stimulus, it remembers the original stimulus.
Studying Infants
• Recognition
• Strauss & Cohen (1978): 5-month-olds’ ability to habituate to
size, color, form & orientation
• 5-month-olds were habituated to a large, black arrow pointing
down
• shown new object, e.g., large white arrow pointing down (measure
preference/looking time)
• Results:
• Immediate: remembered all 4 attributes;
• 15 minutes later: remembered form and colour;
• 24 hours later: remembered only the form
- Thus, infants have a fairly durable memory of the object seen but
other properties less enduring
Studying Young Kids
• Recognition
• Perlmutter & Lange (1978) - 2 year olds – recognition of pictures
was better than adults
• Brown & Scott (1971) – 4-year-olds’ picture memory was at
100% accuracy; even 25 items between 2 exposures
• Sophian & Stigler (1981) – tested young
preschoolers (2y11m), older preschoolers
(4y6m) , 1st graders (6y3m) & college
students recognition memory for faces.
• Found no change between the preschool
ages, but improvement over older groups
• Recognition is generally quite good very early in development
Studying Infants
• Recall
• Object permanence
• the understanding that objects
continue to exist even when they
cannot be seen, heard, or touched
• 8-12 months will:
• search for hidden objects
• show anxiety in parents’ absence
• Maybe even earlier (video)
Studying Infants
• Recall
• Deferred Imitation (e.g., Meltzoff, 1985, 1995 & Bauer, 1997)
• the ability to imitate a previously-seen behaviour hours or days later
• Experimenter demonstrates a novel use of an unfamiliar toy.
• After a delay, infants are given the toy.
• If the infants display the novel behavior more than infants in a control
group, they must remember the action they observed earlier
Studying Infants
• Recall
• Deferred Imitation (e.g., Meltzoff, 1985, 1995 & Bauer, 1997)
• Results: Range of activities and the time over which they remember
and imitate grows in the first year
• By 9-months : 24 hours later can imitate naturally occurring behaviors
and those that are arbitrary, such as pressing a button to make a
beeping sound
• By 14-months : can imitate behaviors after even more time has passed,
and will imitate unusual activities, such as viewing an adult press their
forehead on a panel to make a light go on up to 4 months after seeing
an adult do this
• Thus, at this age, events are represented in long term memory and
can be accessed months later.
Developing Memory
• Implicit and Explicit Memory
• Much of the infant research into memory examines
implicit memory
• Rovee-Collier et al. conditioning experiments
• Implicit memory in older kids
• Hayes & Hennesey Fragmented picture task
• Newcombe & Fox Picture recognition
• But with children who are old enough to talk, research has
focused on explicit memory.
Studying Infants
• Conditioning technique
• Rovee-Collier: studies using mobile conjugate reinforcement
procedure
• Study with infants as young as 2 months old
• Procedure (video)
• A ribbon is tied between a mobile and an infant’s
leg
• Learn to kick to move mobile
• Reactivation treatment
• Questions:
• How long can infants remember?
• What is the role of context?
Studying Infants
• Conditioning technique
• Rovee-Collier: studies using mobile conjugate reinforcement
procedure
• How long?
• delay before test: 48 hours to 2 weeks
• Results
• No forgetting for up to 8 days
• Kicking behaviour will be forgotten within 2
weeks if the event is not experienced again,
but infants can retrieve the memory if it is
appropriately cued
Studying Infants
• Conditioning technique
• Rovee-Collier: studies using mobile conjugate reinforcement
procedure
• Role of context?
• Study with 6-month-olds, 24 hour delay before
test
• Sides of playpen were draped with distinctive
cloth
• At test one group had same cloth surrounding
playpen, other group had a different cloth
• Results
• "no change" group had a higher retention rate
Studying Infants
• Conditioning technique
• Rovee-Collier: studies using mobile conjugate reinforcement
procedure
• Conclusions
• Infants do, therefore, have some implicit/procedural memory
• context plays a role in reinstating memory
• Based on 6 more experiments further investigating the role of
context, Rovee-Collier et el. concluded that infants don't respond
to the context "as a whole", but rather to specific components of
the context
Studying Young Kids
• Implicit Memory
• Hayes & Hennesey (1996) study with 4- 5- and 10-year olds
• Children were shown fragmented pictures and asked to identify them.
• The same fragmented pictures along with some new ones.
• Results:
• Older children identified more pictures
• BUT the priming effect (the degree to which old pictures
were identified faster than new pictures) was the same for
all ages.
• Thus, with age, there was no improvement in implicit
memory.
Studying Young Kids
• Implicit Memory
• Newcombe & Fox (1994) study with 9- & 10-year-olds:
• Children were shown pictures of preschoolers (some were former
classmates)
• Measure of explicit memory: they were asked "Is this a former classmate?”
• Measure of implicit memory: changes in electrical conductance of the skin
• Results: "performance" was poor (but greater than chance) on both explicit
and implicit measures
• BUT there was no difference in skin conductance between the children who did well on the
explicit measure and those who did poorly
• Thus, children who had poor explicit memory still implicitly "recognized"
classmates just as much as children who had relatively good explicit memory.
Developing Memory
• Episodic Memory
• Infantile amnesia - few episodic memories before age 3-4
Studying Young Kids
• Episodic Memory:
• Infantile amnesia - few episodic memories before age 3-4
• Children as young as 2 are able to talk about events that
happened in the past (Fivush & Hamond, 1990; Nelson, 1984;
Nelson & Ross, 1980)
• By 3 or 4 years of age, children can answer questions with
fewer prompts (Hamond & Fivush, 1991)
• Event memory may be explained in terms of scripts, a
knowledge structure containing information about the typical
way in which an event happens
Developing Memory
• Episodic Memory
• Infantile amnesia - few episodic memories before age 3-4
• Several explanations have been proposed:
• Not enough language to successfully store memories
• Sense of self not developed enough, so no autobiographical
timeline to use to organize memories
• Unable to make use of durable gist memories
Studying Young Kids
• Episodic Memory:
• Autobiographical memories
• Simcock & Hayne (2002)
• Magic shrinking machine
• In goes big toy, out comes
identical small toy
• Later asked to describe what
happened, identify pictures,
and re-enact the event
Studying Young Kids
• Episodic Memory:
• Autobiographical memories
• Simcock & Hayne (2002)
• Results
• Youngest groups recalled less
than older groups
• Longer delays led to worse
recall
• Differences between the three measures. Worst recall on verbal task,
best on re-enactments.
• Used words only known at the original session to describe the task
• Conclusions: Children have memories of early events, but may
not have the language skills and knowledge to encode them
Studying Young Kids
• Iconic memory
• Sheingold (1973) replicated Sperling with kids (5, 8, 11, and
adults)
• Array of 7 shapes; central
pointer
• flashed briefly (100 msec), then
pointer
• what was pointer pointing at?
• varied delay between pointer and
array: simultaneous, 0 (right after
disappeared), 50, 100, 150, 200,
250, 500, 1000 msec
Studying Young Kids
• Iconic memory
• Sheingold (1973) replicated Sperling with kids (5, 8, 11, and
adults)
• Results:
• at 50 msec delay, no age effects
• Conclusion:
• 5-years-olds can hold lots of info
in sensory memory
• capacity of sensory memory
doesn’t develop
• There were changes at other delays, suggesting differences in other
stages of processing
Developing Memory
• Short-term memory
• Span
• Serial position
• Encoding strategies
• Rehearsal
• Organization
• Elaboration
• Attention
Developing Memory
• Short-term memory: Span
Mean Number Recalled
• The number of items that children can recall on the
digit span task increases from around 2.5 at age 2, to 7
in adulthood
10
9
8
7
6
5
4
3
2
1
0
Numbers
Letters
0
5
10
Age
15
Developing Memory
• Short-term memory: Span
• According to proponents of the working memory model, the
duration of the phonological loop is a key constraint of how
much information can be remembered
7
Mean Number Recalled
• Correlation
between speech
rate and memory
span
• But Cowan (1997),
suggests that search
time may also play
a role (reflected in
pauses btwn words)
Hulme et al (1984)
6
5
4 years
7 years
10 years
Adult
4
3
2
1
0
0
1
2
3
4
Speech rate (words/sec)
5
Developing Memory
• Short-term memory: Serial position curve
• 6-years-olds show recency but not primacy, 9-year-olds show some
primacy
High
Recall
• May reflect
different
encoding
strategies
Low
Recall
14+ years old
9-year-olds
6-year olds
Early ------------------------------------------------------ Late
(Primacy)
(Recency)
Developing Memory
• Short-term memory: Encoding strategies
• Young children seem to be less efficient at encoding
information (little or no primacy), probably due to
differences in strategy usage
• Rehearsal: repetitively naming information that is to be
remembered
• Organization: information to be remembered should be structured
so that related information is placed together
• Elaboration: embellishing information to be remembered to make
it more memorable
Developing Memory
• Short-term memory: Rehearsal
• Flavell, Beach, & Chinsky (1966)
• Presented kindergarten, 2nd, and 5th grade children with sets of
pictures of common objects and asked them to remember them.
• During 15-sec. delay before each recall test, observed children's lip
movements
Developing Memory
• Short-term memory: Rehearsal
• Flavell, Beach, & Chinsky (1966)
• Results
• Both recall and rehearsal increased with age
• 10% of kindergarteners ---> 85% of grade 5 children.
• Also, within a grade level, children who rehearsed more recalled
more.
• Conclusions
• Rehearsal increases with age, and the frequency of rehearsal
determines memory performance
Developing Memory
• Short-term memory: Rehearsal
• Ornstein, Naus, & Liberty (1975)
• Used an overt rehearsal procedure with 3rd, 6th, & 8th grade
children:
• Children were presented with a series of words, and told that they
must repeat the most recently-presented word during the
interstimulus interval (ISI), and that if they wish they may also
practice other words during the ISI.
Developing Memory
• Short-term memory: Rehearsal - type changes with age
• Ornstein, Naus, & Liberty (1975)
Word
Presented
Eighth-grade student
Third-grade student
1. Yard
Yard, yard, yard
Yard, yard, yard, yard
2. Cat
Cat, yard, yard, cat
Cat, cat, cat, cat, yard
3. Man
Man, cat, yard, man,
cat, yard
Man, man, man, man,
man
4. Desk
Desk, man, yard, cat,
man, desk, cat, yard
Desk, desk, desk, desk
Developing Memory
• Short-term memory: Organization - organizing the
items we want to remember into meaningful categories
• Salatas & Flavell (1976)
• Presented 1st graders with 16 pictures (4 from each of 4
categories).
• Experimenter named the pictures, identified the categories,
and placed the pictures randomly in front of the children.
• Children were told to (physically) sort the pictures in a way
that would help them remember them.
• Result:
• Only 27% of the children sorted the cards according to category.
Developing Memory
• Short-term memory: Organization - organizing the
items we want to remember into meaningful categories
• Other, similar studies have found that:
• Preschool children tend not to use this strategy - children as
old as 8 years often fail to group the cards on the basis of
meaning (instead, they group items randomly)
• In the early school years, children do not spontaneously use
the strategy, but they can be taught it and benefit from using it.
• By the age of 10 or 11 are more likely to group on the basis of
meaning, and they recall more items
Developing Memory
• Short-term memory: Elaboration
• Generating relations between pairs of items so that memory for
the items can be constructed in a meaningful way
• Elaboration is not spontaneously used as a memory strategy
until adolescence, and even then it is not common
• Younger children can be taught to use elaboration but they do
not get the same benefits with respect to increased recall as older
children
Brief Summary
• Short-term memory: Encoding Strategies
• Memory development between preschool years &
adolescence involves age-related changes in the frequency
of use and quality of strategies
• Acquisition of new strategies, refinement of existing, &
generalization to new situations
Developing Memory
• Attention - Ability to selectively attend (and inhibit irrelevant)
develops with age
• Hagen & Stanovich (1977):
• Presented Pairs of pictures
• Ignore one & remember the other
• Intentional Test: recall the central stimuli, as per instructions – recall
increases with age
• Incidental Test: recall the ones they were supposed to ignore
• Results:
• smaller age differences: after age 11, actually remember less of the to-beignored items
• Conclusion: younger kids paying attention to irrelevant stimuli
more than older kids
Developing Memory
• LTM - Use of content knowledge
• Bauer & Mandler (1992)
• tested babies 11.5 to 20 months
• shown a sequence of events
• later allowed to interact with the materials
• e.g., putting a ball in a cup, inverting another cup on top, shaking
cups
• children re-enacted events in sequence shown
Developing Memory
• LTM - Use of content knowledge – scripts
• Hudson & Nelson (1983)
• Told children (4 & 5 yr olds) a story about a birthday party, but put
some elements in wrong order
• When asked to recall the
stories, children often
omitted or corrected the
miss-ordered items
Developing Memory
• LTM - Use of content knowledge
• Chi (1978)
• 10 yr old chess experts vs.
novice adults
• For the children with chess
expertise, an assortment of
shaped pieces on a chequered
board was not a random array
of objects, but a meaningful
situation encompassing
multiple relationships between
the pieces
Developing Memory
• LTM - Use of content knowledge
• Dinosaur knowledge studies (Chi & Koeske, 1983; Gobbo &
Chi, 1986)
• 5 dinosaur child experts & 5 child novices
• Showed pictures of dinosaurs, asked them to
tell all they knew about the pictured dinosaur
• Experts and novices produced similar numbers
of explicit propositions (which could be seen
directly in pictures)
• Experts produced many more implicit
propositions (which could not be seen in the
pictures)
Brief Summary
•
•
•
•
Recall and Recognition developed early
Implicit memory developed early
Episodic last to develop
STM
• Increase in strategies - rehearsal, organization
• LTM
• Increase in general knowledge over first 15 yrs
• Kids use scripts & schemata
Aging
• What abilities decline?
Mean Number Recalled
• STM - slight decline
100
90
80
70
60
50
40
30
20
10
0
Verbal
Spatial
20
40
60
Age
80
Aging
• What abilities decline?
Mean Number Recalled
• Recall - 20% over 40 yrs (25-65)
• Recognition - little decline
100
90
80
70
60
50
40
30
20
10
0
Recall
Recognition
Young
Old
Age
Aging
• What abilities decline?
• Source judgments and encoding details
Mean Number Recalled
70
60
50
40
Remember
Know
30
20
10
0
Young
Middle-old
Age
Older
Aging
• What abilities decline?
• Prospective memory
• no event-based declines (cues given)
• time-based declines (self-initiated cues)
Aging
• Why do they decline?
• “Use it or lose it” (Disuse view)
• Systems view - episodic declines first
• Processing view
• Speed
• lack of inhibition
• transfer-appropriate processing
Memory and Aging
• Older adults learn more slowly
• Remember less learned information
• Declines by age 70
• Timed tasks, unfamiliar tasks
• Recall vs. recognition
• Explicit memory tasks more trouble
• Cognitively demanding tasks
Explaining Declines
• Negative beliefs affect memory skills
• Strategy use not spontaneous
• Attention becomes more effortful (motivation)
• Processing speed decreases
• Sensory, health, and lifestyle changes
• Cohort differences (age and IQ)
• *Declines NOT universal
adulthood
• It is all downhill from here…
• Hit your 70s, your brain shrinks…
• There is general cognitive slowing (probably) which
accounts for some semantic memory problems
• Episodic memory declines too
• Could be due to encoding (Simon’s work)
Inhibition deficit
hypothesis
• More susceptible to interference
• Longer reading times
• More easily distracted using distractor tasks
• Sustained activation of irrelevant material
• In sum, it is probably a combination of overall
cognitive slowing and a problem with inhibition
Summary of Development
(1)Episodic last to develop and first to decline
(2)Increase in general knowledge over first 15 yrs
(3)Increase in strategies - rehearsal, organization
(4)Study age changes with
• habituation
• longitudinal
• cross-sectional