PSY 368 Human Memory Development of Memory. Our focus so far elderlyinfancy childhood adulthood This Week

PSY 368 Human Memory

Development of Memory


Our focus so far

elderlyinfancy

childhood

adulthood

This Week


• Outline for this week• Studying infants & children

• Basic Processes and Capacities• Methodological issues

• Memory in the Elderly• What abilities decline?• Why do they decline?

• Recognition and Recall• Implicit and Explicit

memory• Episodic memory • Standard Model

• Sensory

• STM/WM

• LTM





• How do we test infants?• Non-Nutritive

Sucking • Habituation/

Dishabituation• Conditioning





Will cover next time

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)

Non-Nutritive Sucking method (infants will adjust sucking rate to get preferred stimuli)

Studying Infants

• Recognition Memory in infants

• Recognition Memory in the womb We experience language before we are

even born DeCasper, et al (1994)Fetal heart monitor

Studying Fetuses

We experience language before we are even born

DeCasper, et al (1994)

Same rhyme Different rhyme

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)

Fetal heart monitor

Studying Fetuses

• Recognition Memory in the womb


DeCasper, et al (1994)


Had mothers read rhymes everyday to fetuses during 34-38 weeks of pregnancy


Fetal heart monitor

Studying Fetuses



DeCasper, et al (1994) Had mothers read rhymes

everyday to fetuses during 34-38 weeks of pregnancy



Decreased fetalheart-rate

Baby learned something about the rhyme before it was born!

Fetal heart monitor

Studying Fetuses


Studying Infants

• 2 weeks post-habituation: 2-month-olds prefer to look at a novel scene or object• Habituation technique

• Recognition Memory in infants

Studying Infants

• Habituation techniqueHabituation/Dis-habituation:

• familiarize with A

• then present A or B

• if infant dis-habituates to B, then infant remembers A and can discriminate between A and B

Preference for novelty:

• familiarize with A

• then present A and B together

• 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

• 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?

• Conditioning technique • Rovee-Collier: studies using mobile conjugate

reinforcement procedure

Studying Infants

• 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

• 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


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

• 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

• Episodic Memory:• Autobiographical memories

Studying Young Kids

• Simcock & Hayne (2002)

• Results• Youngest groups

recalled less than older groups

• Longer delays led to worse recall

• Episodic Memory:• Autobiographical memories

• 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• 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

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• 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)

Developing Memory

• Short-term memory: Serial position curve

Early ------------------------------------------------------ Late(Primacy) (Recency)

Low Recall

High Recall

14+ years old9-year-olds6-year olds

• 6-years-olds show recency but not primacy, 9-year-olds show some primacy

• May reflect different encoding strategies

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

Desk, desk, desk, desk

Desk, man, yard, cat, man, desk, cat, yard

4. Desk

Man, man, man, man, man

Man, cat, yard, man, cat, yard

3. Man

Cat, cat, cat, cat, yardCat, yard, yard, cat2. Cat

Yard, yard, yard, yardYard, yard, yard1. Yard

Third-grade student

Eighth-grade student

Word Presented

• Short-term memory: Rehearsal - type changes with age• Ornstein, Naus, & Liberty (1975)

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-be-ignored items

• Conclusion: younger kids paying attention to irrelevant stimuli more than older kids

Developing Memory

• 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

• LTM - Use of content knowledge

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

• 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

• LTM - Use of content knowledge

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?• STM - slight decline

Aging

• What abilities decline?• Recall - 20% over 40 yrs (25-65)• Recognition - little decline

Aging

• What abilities decline?• Source judgments and encoding details

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

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PSY 368 Human Memory Development of Memory. Our focus so far elderlyinfancy childhood adulthood This Week