PSY 368 Human Memory

PSY 368 Human Memory

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?

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


• Outline for this week• Studying infants & children

• Basic Processes and Capacities• Methodological issues

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

• Brain change

• Cognitive Changes• Episodic

Memory

• STM/WM

• Implicit Memory

• Strategies

• Theories

The Aging Brain

• On average, the brain shrinks 5% to 10% between the ages of 20 and 90

• May result from a decrease in dendrites, damage to myelin sheath, or the death of brain cells

Region As we age, this region …

Overall brain Shrinks

Ventricles Expands

Frontal lobes Shrinks most rapidly

Temporal lobes Shrinks slowly

Hippocampus

Shrinks slowly, then accelerates (possibly due to disease)Loses 20–30% of its neurons by age 80

Occipital lobes Shrinks slowly

• Some areas of the brain shrink more than others

The Aging Brain

• On average, the brain shrinks 5% to 10% between the ages of 20 and 90

• May result from a decrease in dendrites, damage to myelin sheath, or the death of brain cells

• Some areas of the brain shrink more than others

• Shrinkage of the prefrontal cortex is linked with a decrease in working memory and other cognitive activities

• A general slowing of function in the brain and spinal cord begins in middle adulthood and accelerates in late adulthood

• Aging has been linked to a reduction in the production of certain neurotransmitters

The Aging Brain: Adapting

As the brain ages, it adapts in several ways:• Neurogenesis: the generation of new

neurons throughout the life span

• Dendrite growth increases from the 40’s to 70’s

• Older brains rewire to compensate for losses

• Hemispheric lateralization can decrease; may improve cognitive functioning

Aging: Episodic Memory

• Episodic memory declines steadily through the adult years, across many task:• Verbal and visual materials• Rivermead Behavioural Memory Test (everyday

memory situations)• Memory for card hands• Memorizing passages• Memory for conversations

• The magnitude of the decline depends on the nature of the task and the method of testing (recall vs recognition).


• Episodic memory declines steadily through the adult years• Recall and recollection tests

• Recall - 20% over 40 yrs (25-65)

• Recognition - little decline

• Age effects are clearest in recall tests, which lack external cues, while recognition tends to be relatively preserved in the elderly.


• Age effects are clearest in recall tests, which lack external cues, while recognition tends to be relatively preserved in the elderly.• This difference may reflect a combination of:

• Fewer retrieval cues in the recall task

• A greater involvement of association in free recall

• Taking longer to perceive and process materials

• Whether recognition is impaired or not depends on the nature of the task:

• If familiarity (“knowing”) is sufficient—no deficit

• If recollection (“remembering”) is necessary—some impairment

• Source memory impairments: when and where information is learned

• Episodic memory declines steadily through the adult years• Recall and recollection tests


• What abilities decline?• Source judgments and encoding details

Parkin & Walter (1992)


• Autobiographical Memories, Piolino et al (2002)• Recall of general (semantic) information from a time

period: names of people, an important date, a specific address

• Recall of episodic memory from a period: first meeting with spouse, a day during a holiday trip

• Participants: 40s, 50s, 60s ,70s

• Semantic memories: Older adults did equivalently with young on information recall

• Episodic memories: More contextual detail in event memory, this is poorer for older folks.

Aging: Prospective Memory

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• Laboratory studies• no event-based declines (cues given) • time-based declines (self-initiated cues)

• Unlike laboratory situations, in real-life prospective memory scenarios the elderly often perform better than younger adults.• Example Tasks:

• Ask participants to make a telephone call or send a postcard at a specified time.

• Rationale:• Older people are more aware of their memory limitations and

compensate with various strategies, such as:• Diaries• Reminders

• Older people live more ordered and structured lives, making it easier to form plans.

• Older people may have been more motivated to perform well on a memory task; younger people can explain memory slips by “being too busy”.

• WM span progressively declines with age• Park (2006)

Aging: STM/WM

Aging: STM/WM

Type of Memory Example Test General Findings

Verbal span Digit span Declines by < 1 item

Visual span Corsi block tapping Declines by < ½ an item

Verbal working memory

Recalling words in alphabetical order

Modest decline

Sentence span Small decline

• WM span progressively declines with age• But it is a very small decline• Effects are larger when tasks involve speed of

processing or episodic, long-term memory

• May et al. (1999)• The WM decline may be due to a build up of

proactive interference that older adults are less able to inhibit

Aging: Implicit Memory

• Results are mixed, due to the wide range of implicit processes

• Generally:• When the response is obvious and performance is measured in

terms of speed improvements

• The elderly perform well

• When the response is non-obvious, novel associations must be learned

• Older adults are impaired

• This is often the case for learning about new technologies

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Aging: Implicit Memory37

Aging: Memory Strategies

• Strategies are deliberate activities designed to improve memory (e.g., tie string around finger), • Older adults don’t spontaneously use these as much as younger

adults • True for both encoding and retrieval processes

• Why?• “Disuse view” use these strategies because of longer time away from

educational system

• Diminished attentional capacity view: Fewer attentional resources available to engage in encoding strategies (and maybe they don’t execute them as well)

• Memory self-efficacy view: Older individuals don’t have confidence in their own memory systems, so they expect poor memory and don’t use the strategies

• Using strategies helps remembering, but doesn’t fully account for age differences in recall (Herzog et al., 1998)

Theories of Aging

• Why do they decline?• “Use it or lose it” (Disuse view)• Systems view• Processing views

• Speed• Lack of inhibition• Transfer-appropriate processing

Theories of Aging

• Why do they decline?• “Use it or lose it” (Disuse view)

• Analogy to exercise and muscle atrophy, if you aren’t using memories (or memory systems), then functioning declines

• Not a lot of support for this view• Many tasks that are still important for day-to-day

functioning still show age related impairments

• Problems with circularity in the data

• Older people with good memory functioning use it more, which in turn leads to better memory functioing

Theories of Aging

• Why do they decline?• Systems view

• Episodic memory system is last to develop and first to decline• Predicts across the board effects on memory

systems

• But, can find variability in performance depending on task, (so maybe it isn’t the system, but rather processes)

Theories of Aging

• Why do they decline?• Processing views

• Speed• Salthouse (1996) Many of the cognitive effects of aging

are caused by reduced processing speed

• Digit Symbol Substitution Test (DSST) is a good predictor of age deficits

• Lack of inhibition• Hasher and Zacks (1988) Inhibition Deficit Hypothesis

of Aging:• A major cognitive effect of aging is the reduced

capacity to inhibit irrelevant stimuli• May result in build up of proactive interference

Theories of Aging

• Why do they decline?• Processing views

• Transfer-appropriate processing• Age related declines are related to the availability of

appropriate/good quality cues at retrieval

• For tasks in which good cues are available, age related memory differences typically disappear

Brief summary• Memory: Memory changes during aging but not all in the same way

• Working memory and perceptual speed: decline during the late adulthood years

• Episodic memory: younger adults have better episodic memory• Source memory: the ability to remember where one learned something

• Decreases with age during late adulthood

• Semantic memory: does not decline as drastically as episodic memory• Exception: tip-of-the-tongue phenomenon

• Implicit memory: shows less aging declines than explicit memory

Documents

PSY 368 Human Memory