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+ Chapter 12 Memory in Childhood. + Infantile Amnesia Infantile Amnesia: The tendency for adults to have few autobiographical memories from below the.

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Presentation on theme: "+ Chapter 12 Memory in Childhood. + Infantile Amnesia Infantile Amnesia: The tendency for adults to have few autobiographical memories from below the."— Presentation transcript:

1 + Chapter 12 Memory in Childhood

2 + 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) 2

3 + 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 3

4 + 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 4

5 + Mnemonic Abilities in Infancy 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 5

6 + Mnemonic Abilities in Infancy 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 6

7 + 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 7

8 + Rovee-Collier Video http://www.youtube.com/watch?v=lPJiB-oGMN0 8

9 + Declarative Memory Development 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 Rovee-Collier’s (1989) Mobile Conjugate Reinforcement Paradigm 9

10 + Declarative Memory Development 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 Rovee-Collier’s (1989) Mobile Conjugate Reinforcement Paradigm 10

11 + Declarative Memory Development 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 11

12 + Mnemonic Abilities in Infancy 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 12 Meltzoff’s novel toy

13 + Mnemonic Abilities in Infancy 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 13

14 + 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? 14

15 + 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) 15

16 + 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 16

17 + Changes at the Neural Level 17 2 YearsNewborn6 Months More myelination More interconnections More neurons in the hippocampus and in prefrontal areas

18 + 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 18

19 + Changes in Brain by Age 19

20 + Sensitive Periods in Development Neural changes correlate with sensitive periods in development and important milestones. 20

21 + 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 21

22 + 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) 22

23 + Candid Camera Demo CD – Remember This Message 23

24 + Further Memory Developments WM ComponentTest Phonological LoopVerbal Storage (Digit Span) Central ExecutiveComplex 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. 24

25 + Further Memory Developments 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 25 Adapted from Chi (1978).

26 + Further Memory Developments 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 26

27 + Older Children Use More Sorting Strategies 27 (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.

28 + Further Memory Developments 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 28

29 + 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 MemoryGist Memory Brainerd and Reyna (2004) 29

30 + 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) 30

31 + 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 31 From Brainerd and Reyna (2004).Copyright © 2004 Elsevier. Reproduced with permission.

32 + 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 32 Data from Russo et al. (1995).

33 + 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 33

34 + 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 34 Can infants store autobiographical memories?

35 + 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 35 Can infants store autobiographical memories? Autobiographical Memory in Infancy

36 + 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 36 Simcock and Hayne’s (2003) “Magic Shrinking Machine” Autobiographical Memory in Infancy

37 + 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 37 Simcock and Hayne (2003) From Simcock and Hayne (2003). Copyright © American Psychological Association. Reproduced with permission.

38 + 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. 38 Fivush and Nelson’s (2004) Social Cultural Theory

39 + Explanations for Infantile Amnesia 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 39

40 + Explanations for Infantile Amnesia 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 40

41 + Explanations for Infantile Amnesia 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 41

42 + Explanations for Infantile Amnesia 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. 42 Summary

43 + Ceci & Bruck Video http://www.youtube.com/watch?v=vVh22znRd2Q 43

44 + 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 44 The Effect of Leading Questions Accuracy

45 + Children as Witnesses 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. 45 Suggestibility

46 + Children as Witnesses 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. 46 Suggestibility

47 + Children as Witnesses 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 47 How to Maximize Accuracy


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