+ chapter 12 memory in childhood. + infantile amnesia infantile amnesia: the tendency for adults to...

+

Chapter 12Memory in Childhood

+Infantile Amnesia

Infantile Amnesia: The tendency for adults to have few autobiographical

memories from below the age of 5

Studying infantile amnesia can be difficult, as it is: Hard to verify memories from childhood -- researchers focus

on dateable, verifiable events, such as the birth of a sibling Hard to know whether childhood memories are genuine

recollections or are reconstructed from stories and photographs Genuine memories tend to be more visual, less verbal,

more emotional, more complete (Crawley & Eacott, 2006)

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+Infantile Amnesia Sheingold and Tenney (1982):

Participants: College students and

children (ages 4–12) Task:

Answer specific questions about a sibling’s birth from when they were 3–11 years old e.g. “Who took care of

you while your mother was in the hospital?”

Mothers were asked the same questions

Results: If the birth occurred after 3

years old, very little forgetting occurred Even if it occurred many

years ago If birth occurred before 3

years, virtually nothing was remembered

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+Mnemonic Abilities in Infancy

Infants’ linguistic skills are highly limited, so: Experimenters can’t use verbal

instructions Tasks require motor, rather

than verbal responses But infants’ motor responses

are also limited It is hard to establish whether

they are consciously aware of their memories i.e. are they declarative or

implicit?

Memories are considered declarative, provided they pass two filters (Richmond & Nelson, 2007): Amnesia Filter:

If an amnesiac can do the task, then it’s implicit

If not, then it’s declarative Parameter Filter:

If the memory is affected by factors known to influence declarative tasks in adults, then it’s also declarative, e.g.: Changes in study time Retention interval Contextual changes

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Infants display some (limited) mnemonic abilities almost immediately after birth DeCasper and Fifer (1980):

Task: 3-day-olds learned that sucking on a pacifier activated a tape

recording with the voice of either: The infant’s mother A stranger

Results: Infants sucked on the pacifier more when it activated the

familiar voice of their mother Querleu et al. (1984) replicated the results in infants 2 hours old

Conclusion: Newborns have the ability to remember both their mother’s

voice and the action that produces the sound of her voice

Implicit Memory in Development

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Declarative memory abilities develop later than implicit memory

Originally, infants were assumed to lack explicit memory This view has changed in light of recent data. It is now assumed that declarative memory is possible in

children far younger than once thought.

Declarative (Explicit) Memory Development

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+Declarative Memory Development

Conjugate means “paired.”

Guiding Principle: Avoid underestimating baby’s memory by using what interests them e.g. a colorful mobile hanging

over a baby’s crib Attach it to the baby’s foot

with a ribbon When the baby kicks, the

mobile moves They are rewarded when

they kick by the mobile’s movement Quickly learn to kick in the

mobile’s presence via operant conditioning

Three phases of the paradigm: Baseline:

Record how often the baby kicks when the foot isn’t attached to the mobile

Learning: Infants learn that kicking (response)

causes the mobile to move (reinforcement)

Test: The ribbon is detached from the

mobile (no reinforcement during test)

If they kick more than baseline in the presence of the mobile, they remember the connection

The retention interval between learning and test can be manipulated

Rovee-Collier’s (1989) Mobile Conjugate Reinforcement Paradigm

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+Rovee-Collier Video

http://www.youtube.com/watch?v=lPJiB-oGMN0

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Rovee-Collier et al.’s (1980) results: At short delays:

Both 2 and 3-month-olds showed evidence of retention

After 2 days: 2-month olds were back at

baseline After a week:

3-month olds still show a reliable effect

Presenting a reminder (a moving mobile) before testing reactivated kicking: After a 2-week delay: Retention

bounced back up to its initial levels After a 1-month delay: Still

significant kicking behavior


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The learned kicking behavior is quite specific: Perceptual discrimination:

If the babies were trained on an mobile with yellow blocks, they wouldn’t respond to a mobile with metal butterflies instead However, if they’re trained on many different mobiles, they

would then generalize the kicking response to novel mobiles It is as if they learned the mobile “concept”

Context-sensitivity: If an infant was trained in a crib but tested in the kitchen, they

wouldn’t kick If the crib’s décor was changed, the amount of kicking would be

reduced


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Is it declarative memory? Probably (Rovee-Collier, 1997):

Infants’ performance is determined by factors that are more important in declarative than implicit memories, e.g.: Participant’s age Retention interval Context

The Mobile Conjugate Reinforcement paradigm isn’t suitable for infants over 7 months, so: Hartshorn and Rovee-Collier

(1997) introduced a similar task for older infants: Infants instead learn to

press a lever to make a miniature train move

They demonstrate memory by pressing the lever even when the train no longer moves

The Mobile Conjugate Reinforcement Paradigm

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Background: Piaget believed that infants

didn’t possess the ability to do deferred imitation until 2+ years

Deferred Imitation Task: Experimenter produces a

sequence with objects e.g. use a mallet to hit a

metal plate Delay of varying

lengths The infant then

tries to imitate the action

Meltzoff (1985) Participants:

14-month-olds 24-month-olds

Exposure Conditions: Imitation: Observe experimenter

pull the toy apart Control: Observe experimenter

move the toy in a circle Baseline: Give the novel toy to

the infant without pre-exposure Delay:

Wait 24 hours before infant is given the toy

Deferred Imitation

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Meltzoff’s novel toy


Results: 14-month-olds

45% of infants in the experimental condition imitated the experimenter’s action

Only 7.5% of infants in the baseline/control conditions imitated

24-month-olds 70% of infants in the

experimental condition imitated

Follow-up Experiments: Collie and Hayne (1999)

6-month-olds remember around 20% of the actions they saw 24 hours earlier

Bauer et al. (2000) 60% of 16-month-olds

produced actions in the right order after a 12-month delay

Deferred Imitation

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+Deferred Imitation

Is deferred imitation declarative or implicit memory?

Evidence that deferred imitation requires declarative/explicit memory: Adult amnesiacs show little evidence of deferred imitation

(McDonough et al., 1995) Amnesiacs are selectively impaired in declarative memory

Preverbal infants who imitated were later able to verbalize their performance Only declarative memories are likely accessible to

language

Evidence of Declarative Memory?

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+Principles of Memory Development

Older infants typically encode/store information faster than younger infants e.g. 6-month-olds require twice as much exposure to do deferred imitation,

compared to 12-month-olds

Older infants remember information over longer delays e.g. 18-month-olds kick in the mobile conjugate reinforcement paradigm up to 12

months after training; 6-month-olds only remember for about 2 weeks

Older infants make use of a greater variety of retrieval cues (their memories are more flexible) e.g. 18-month-olds still imitated when the toy was changed slightly; younger infants

did not (Hayne, Boniface, & Barr, 2000)

Forgotten memories can be retrieved when a reminder is presented 3 minutes of exposure to the experimenter moving the mobile 1 day before testing

vastly extended the retention interval during which they exhibited memory

Hayne (2004)

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+Developmental Cognitive Neuroscience

Numerous developments during the first 2 years of life contribute to better mnemonic abilities: Attention improves Language starts to be acquired World knowledge accumulates The brain is developing

Schacter and Moscovitch (1984) Implicit memory is controlled by a memory system likely present at birth

Striatum Cerebellum Brainstem

Declarative memories depend on a late-developing memory system Reaches maturity between 8–10 months

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+Changes at the Neural Level

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2 YearsNewborn 6 Months

More myelination

More interconnections

More neurons in the hippocampus and in prefrontal areas

+Developmental Cognitive Neuroscience Brain regions underlying declarative memory continues to develop

well into childhood Medial Temporal Lobe

Hippocampus Dentate gyrus—develops for 1 year after birth Other parts not fully developed until 2–8 years

Parahippocampal complex Prefrontal cortex

Synaptic density increases until 24 months Not fully matured until around 20 years

Axons in the central nervous system Continue to myelinate over the first year

Speeds up processing and learning

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+Changes in Brain by Age

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+Sensitive Periods in DevelopmentNeural changes correlate with sensitive periods in development and important milestones.

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+Developmental Cognitive Neuroscience

Does not simply describe changes Helps to explain how and

why changes arise

Offers a partial understanding of the differences between types of memory e.g. declarative vs. implicit

Often relies heavily on correlations between the rate of brain maturation and behavioral performance But correlation does not

imply causation!

Benefits of the Approach Limitations to the Approach

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+Further Memory Developments

Declarative memory continues to improve into childhood, due to a number of inter-related factors: Basic capacity in short-term memory/working memory increases over the

years Subvocally rehearse faster/more Adopt better strategies

Learn and use new strategies (e.g. rehearsal) Accumulate more knowledge

Helps form schemas to organize memories Develop better metamemory:

Knowledge about one’s own memory and how it works Helps children select the best strategy to use

Siegler (1998)

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+Candid Camera Demo

CD – Remember This Message

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WM Component Test

Phonological Loop Verbal Storage (Digit Span)

Central Executive Complex Memory Span (Backward Digit Recall)

Visuo-Spatial Sketchpad

Visuo-Spatial Memory (Visual Pattern Recall)

Basic Capacity

Gathercole et al. (2004) studied working memory (WM) development between the ages of 4–15 years

Results: All three components developed over time WM structure remained fairly constant over time

From Gathercole et al. (2004). Copyright © American Psychological Association. Reprinted with permission.

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Older children possess more knowledge Memory performance is

often better when the learner has a relevant schema for new knowledge

Chi (1978) Participants:

10-year-old chess experts

Adult chess novices Task:

Digit recall and reproduction of chess positions

Results: Adults performed better at digit recall Children performed over 50% better at chess recall

Schneider et al.’s (1993) Follow-Up: Children and adults of equal chess expertise

performed equally Both performed better than chess novices

Conclusion: Memory for chess positions depends largely on

expertise, rather than age

Content Knowledge

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Adapted from Chi (1978).


Older children are more likely than younger ones to employ memory strategies Evidence comes from

categorized list recall: Task:

Participants are randomly presented with words/pictures from various categories

They are then asked to free recall the items

Results: Adults (Weist, 1972)

Rehearse words by category Words are recalled by category

(i.e. they “clustered”) Organizational strategies lead to

better recall Children aged 8–17

(Schneider, Knopf, & Stefanek, 2002) Older children used more sorting

strategies Older children clustered more Both these strategies increased

steadily over development

Memory Strategies

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+Older Children Use More Sorting Strategies

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(a) Free recall and (b) sorting during learning and clustering during recall assessed by ratio of repetition (RR) at ages 8, 10, 12, and 17. From Schneider et al. (2002). Copyright © American Psychological Association. Reprinted with permission.


Metamemory knowledge increases over development e.g. younger children tend to drastically overestimate their memory

span (Yussen & Levy, 1975)

Metamemory knowledge is a moderate predictor of memory performance, R =.41 (Schneider & Pressley, 1989) A robust metamemory helps children to select appropriate learning

strategies The correlation isn’t perfect because children might not be motivated

to use their strategies

Metamemory

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+Verbatim and Gist Memory

Contain accurate and detailed information about to-be-remembered stimuli Reflects the actual

experience Improves over childhood

General semantic information about to-be-remembered stimuli Reflects a general

understanding of an experience

Improves over childhood Children grow to extract

more meaning from information e.g. they start to

spontaneously categorize items like adults

Verbatim Memory Gist Memory

Brainerd and Reyna (2004)

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+When Improvements Go Wrong

Older children form more gist memory traces This is generally advantageous, but this occasionally leads

to errors when: The learning task leads older children to produce more

gist memories than younger children do The memory test requires verbatim recall/recognition Greater gist memory increases the likelihood of false

recall/recognition of information very similar in meaning to the to-be-remembered information

This has largely been studied with the Deese–Roediger–McDermott (DRM) paradigm – false memory paradigm

Brainerd and Reyna (2004)

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+Deese-Roediger-McDermott (DRM) Paradigm Task:

Participants presented with a list of words e.g. NURSE, SICK, HOSPITAL,

and PATIENT All words are related to a

missing target word (e.g. DOCTOR)

Participants are then asked to recognize words they saw before, including the missing word

Result of Interest: How often do people mistakenly

recall/recognize having seen the missing target word?

Developmental Results: False recall/recognition increases

progressively during childhood

Conclusion: Older children are better at semantic

processing So they tend to categorize all the words

under the missing word, which becomes highly active

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From Brainerd and Reyna (2004).Copyright © 2004 Elsevier. Reproduced with permission.

+Declarative vs. Implicit Memory Development

Implicit memory is pretty well established at birth and does not seem to improve with age There are a few discrepant results, however.

Declarative memory starts off less developed, but it then begins to improve rapidly.

Russo et al. (1995) compared implicit to declarative memory development. Task:

Asked children to ID degraded (or intact) pictures of objects Implicit measure:

Perceptual priming Declarative measure:

Free Recall

Implicit

Declarative

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Data from Russo et al. (1995).

+Declarative vs. Implicit Memory Development

Why the general lack of implicit improvement? Compared to declarative memory, implicit memory involves

more basic processes. Implicit memory is relatively unaffected by other cognitive

skills, such as: WM capacity Content knowledge Strategy Metamemory

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+Autobiographical Memory in Infancy

Nelson (1988) Tape-recorded the “crib talk” of Emily between the ages of 21 and 36

months Results:

At 21 months, Emily was recalling (often fragmented) events Most from the previous day Some from up to 6 months before!

At 24 months, Emily was: Constructing explicit rules and generalizations Making speculations about the future

At 36 months, Emily stopped talking to herself in the crib Conclusion:

2-year-olds can encode and remember specific episodes Caveat:

This was only a single child

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Can infants store autobiographical memories?

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Fivush, Gray, and Fromhoff (1987) Interviewed ten children

(average age = 33 months) and their parents about recent and distant events

The children were able to answer over 50% of questions about both types of events Best recall for

activities/objects, rather than people/location

A major factor determining how much can be remembered: Whether they possessed

language skills to talk about the event at the time it happened

At longer delays (4+ years) before recall, the infant’s age at encoding is highly important: If under 2, generally no

memory If 3, then 50% recall If 4+, then nearly all recalled

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Can infants store autobiographical memories?

Autobiographical Memory in Infancy

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Memory in young children is typically assessed by verbal report However, they have limited

verbal skills Research based on verbal

report likely underestimates young children’s memory

Simcock and Hayne developed the “magic shrinking machine” task to address this issue They included nonverbal

memory tests

“Magic Shrinking Machine” Participants:

Children age 24–48 months

Task: Children saw large objects

go into a machine, but small objects come out

After 24 hours, children were given three memory tests: Verbal recall Nonverbal photograph

recognition test Behavioral reenactment

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Simcock and Hayne’s (2003) “Magic Shrinking Machine”

Autobiographical Memory in Infancy

+The Magic Shrinking Machine

Simcock and Hayne’s nonverbal tests revealed hidden memory retention by: Relying less on language Providing more retrieval cues to the children

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Simcock and Hayne (2003)

From Simcock and Hayne (2003). Copyright © American Psychological Association. Reproduced with permission.

+Explanations for Infantile Amnesia

Pre-linguistic memories are hard to express later using language. Language skills at the time of an event dictate what they can recall

subsequently (Simcock & Hayne, 2002).

Children whose parents have an elaborative reminiscing style later report more and fuller childhood memories. Nelson’s (1989) Museum Study:

When mother–child conversations about the museum trip were freely interacting, rather than practical, the children remembered more.

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Fivush and Nelson’s (2004) Social Cultural Theory


Freud (1915/1917) Proposed that infantile amnesia occurs through repression, with

threat-related thoughts being: Banished to the unconscious mind Transformed into more innocuous memories called “screen

memories” Problems with the theory:

No evidence supports it Fails to explain why adults cannot remember positive or neutral

events from childhood

Repression

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Howe and Courage (1997) Must have a sense-of-self to form autobiographical memories.

Develops around 2 years. Visual-self recognition: recognizing one’s reflection in the

mirror Provides a schema for autobiographical memories.

Evidence (controlling for language): Self-recognizers had better memory for personal events. Pre-self recognizers never had good autobiographical memory.

Why can 2-year-olds remember events for months, but not into adulthood? Howe and Courage argue that these memories aren’t rehearsed

much.

Cognitive Self Approach

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Nelson’s (1989) Museum Study: Elaboration provides the children with ample opportunities to

rehearse their own memories. An elaborative style is more common in Western Cultures.

First memories in Western cultures tend to be earlier and are more elaborated and emotional than in many Eastern cultures. This could also be because Western children are more

inclined to talk about their personal experiences .

Fivush and Nelson’s (2004) Social Cultural Theory

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The cognitive self approach and the social cultural theory both have supportive evidence and are not mutually exclusive. The onset of autobiographical memory could depend on the

emergence of self. Subsequent memory expression is heavily influenced by social,

cultural, and linguistic factors.

Most research into infantile amnesia relies on correlational evidence. Causality is difficult to prove under these circumstances.

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Summary

+Ceci & Bruck Video

http://www.youtube.com/watch?v=vVh22znRd2Q

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+Children as Witnesses

Are traumatic events more memorable than nontraumatic ones? Not terribly (Cordón et al., 2004):

Both are influenced by age, delay, and nature of the event

Are children more suggestible than adults? Yes (Ceci, Baker, & Bronfrenbrenner,

1988): Younger children are more biased than

are older children by leading questions: Questions that carry with them an

implication as to the correct answer 10- to 12-year-olds are no more

suggestible than adults

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The Effect of Leading Questions

Accuracy


Thompson, Clarke-Stewart, and Lepore (1997) found that young children’s responses are largely consistent with the view of their questioner. The responses of 5 to 6-year-olds to questions about potential abuse when

questioned by: Neutral interviewers:

Are generally accurate Accusatory interviewers:

Are biased in favor of guilt Exonerating interviewers:

Are biased in favor of innocence

Young children continue to reflect the prior influence even when: Questioned by a new, non-suggestive interviewer. Warned that the previous interviewer may have been mistaken.

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Suggestibility


Young children are suggestible because of their: Social compliance

They yield to authority figures They lack social support to stand up for their views

Cognitive incompetence They come to believe their distorted reports because of limitations

in: Processing Attention Language abilities

Inability to source monitor They often confuse real-life and television events.

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Suggestibility


Reduce social compliance Avoid leading questions at any point in the questioning process

Garven, Wood, and Malpass (2000)

Train effective source monitoring techniques Thierry and Spence (2002)

Reinstate the encoding context According to the encoding specificity principle, memory should be

maximal when the encoding context and the retrieval context match Priestley, Roberts, and Pipe (1999)

Use nonverbal recall techniques Asking children to draw what they remember before asking for a verbal

report can elicit idiosyncratic retrieval cues and nonverbal information Gross and Hayne (1999)

Children remembered 30% more in the drawing condition, which only increased (without adding errors) at longer delays

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How to Maximize Accuracy

+ chapter 12 memory in childhood. + infantile amnesia infantile amnesia: the tendency for adults to...

Documents

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