Chapter 14 - Memory in Childhood

Memory Development in Childhood: Implicit Memory

- *"First-in, last-out rule"* - Remains stable across lifespan - Reaches adulthood levels very soon in development: children demonstrate similar levels of of familiarity, perceptual identification tasks - Does not follow the slower developmental path of other memory systems - Some argue that most of infant learning is implicit learning (ex. kick study)

Measures of the Cognitive Self in Infants

- *Visual recognition/mirror test:* - Babies are attentive to the mirror at 3 months - Attentive to playmate at 6-12 months - *Self-recognition at 20-24 months* - *Linguistic markers of self-schema:* - Babies use I vs. you pronouns at 22-24 months - ~24 months, babies use grammatical morphemes indicating past tense

Infantile Amnesia and Schemas

- *Young children do not have the same schemas as adults* - Fail to structure memory appropriately: - Adults structure AB memories within their life-narrative (helps to structure recall, but infants don't have this) - Children do not attend to the same information as adults

Social Cognitive Theories of Infantile Amnesia

- *Young children lack the language and social skills to construct meaningful narratives* - Language development - *Socialization* and development of logical thinking - Implication: that early memories are *inaccessible* or *incomprehensible* to adults

Event Narratives and Infantile Amnesia: Tessler (1986)

- 3-year-olds and their mothers visited a museum - None of the children remembered any of the objects they'd seen unless they'd discussed them with their mothers - Creating a narrative together cemented particular objects in memory - Perhaps this promotes understanding of the events, the way a schema would?

Infantile Amnesia

- Adults rarely recall memories for the first five years of life - Generally have no memories from ages 2-3 - What is different about these memories? - Memories that are forgotten are either: inaccessible or unavailable - Caveat with childhood memories: they may be inaccurate because what we are remembering are family legends (did they happen? Like that? At that time? Is it important enough to the child to have been retained?

Infantile Amnesia and First Memories (Bruce, Dolan, & Phillips-Grant, 2000)

- At what age do children start forming memories that are later "retrievable"? - Remembered memories vs. known memories from childhood - *Known event memories*: personal semantic knowledge (we know we did something because someone/thing else told us, not because we remember doing it) - Personal recollections vs. memories that were formed during childhood amnesia - When does the switch between the two occur? - Collected 2 memories: one remembered, one known - Participants dated memories - Median age of known events: 3.2 years - Median age of remembered events: 6.1 years - Average of the two: 4.5 years (switch from childhood amnesia to personal memories)

Childhood Memory Development Beyond Infancy

- Changes that occur with improved LTM: - Improved WM ages 4-25 - More knowledge about the world (chess study with children) - More organization because of increased use of strategies - *Implicit memory develops early and remains ~ the same throughout childhood*: procedural skills - adults don't learn them faster than children

Evidence of Early Childhood Memories: Meltzoff's Deferred Imitation Paradigm

- Children 14-18 months old - Baby watches adult perform some novel *target action* on an object - Baby *not* allowed to interact with object - Retention interval - Test: baby allowed to interact with novel object - 6-month olds: showed deferred imitation up to 2 days later without a reminder, 10 weeks later with - imitation was context-specific to location where the behaviour was learned - 3-month olds: hard to test because of motor delay - Exposure at 3 months + learning delay = evidence of learning at 6 months

Childhood Semantic Memory

- Children have less knowledge than adults for the vast majority of information in the world - Semantic memory development is confounded by all the other things we improve on as we get older - This study contrasted child chess experts with adult non-experts - Assigned both groups tasks for learning digits and chess-based task - Adults did better on digit task (more experience working with numbers) - Children did better on chess task (more expertise) - *It is the difference in expertise between children and adults that drives LTM differences*

Neurological Explanations of Infantile Amnesia

- Infantile amnesia results from immaturity of brain structures: - Hippocampus and frontal lobes grow rapidly in early life, with rapid development and myelination until age 2 - Amygdala matures early and allows for procedural memories - Perhaps the immature HC means that the memories are never properly formed, and so infants do not have episodic memories (implication: these memories are *not* available as adults) - However, infants may remember events over months while still in childhood: - Burst in childhood neurogenesis since infancy may "bury" memories (implication: there memories are not *accessible* in adulthood)

Other Evidence of Early Childhood Memories

- Memory for location: 2-year-old can remember a hidden toy's location 24 hours later - But is this evidence of autobiographical memory? - Same issues as studying birds' caching behaviours

Theoretical Explanations of Infantile Amnesia

- Neurological: neural substrates of episodic memory not yet developed enough - Cognitive: failure to structure memory appropriately (sense of self; adult schemas; language, socialization, and narrative function) - However, it is a robust phenomenon that clearly exists!

Improved Working Memory in Childhood

- Pickering, Ambridge, & Wearing (2004) - Improvements in all facets of working memory: - Verbal storage, complex memory span, visuospatial memory - Individual differences in children on these tasks are predictive of later life - General intelligence, income, success at school, etc.

Cognitive Explanations of Infantile Amnesia

- Prior to 2-3 years, children lack the *concept of self* necessary for enduring personal memories (*the cognitive self*) - Others say this is just another way of discussing the socially accessible memory system

Strategies and Organization in Childhood Memories

- Schleepen and Jonkman (2012) - 6-12-year-olds given pictures of fruits, animals, and clothes - Retention interval - Test: free recall - Measured amount of clustering in children - *Clustering increased as children got older, and recall increased with age as a result* - Also related to WM capacity - increases with age

Issues with Rovee-Collier's Kick Study Paradigm

- The learning is very specific (unless exposed to variations during encoding phase) - Rapid forgetting - Is this episodic memory? Or just *conditioning*?

Infantile Amnia and First Memories

- Usher and Neisser (1993) - Memory for early life events in university students (birth, hospitalization, death in family, family move) - Preselected based on screening questionnaires - Mothers asked to verify accuracy of memories - *Age of offset*: when infantile amnesia lifted - Around 2 for hospitalization and birth of a sibling, 3 for moving houses and death of a loved one (likely because birth of a sibling is so important) - Only 12% of participants' recalls were labeled "incorrect"

Rehearsal and Review in Infantile Amnesia (Usher and Neisser, 1993)

- Were external sources of information about these memories available? (photos, videos, family stories, etc.) - Most common source in this study was family stories - These stories were *negatively related* to recall up to age 3 - Is this the product of reconsolidating? (The children had an episodic memory of the event, but it changed every time they were exposed to information about the event: less confident in their own memory, source monitoring problem.) - Is this the product of interference? (Newer information about the event being more accessible - retroactive interference?)

Evidence of Early Childhood Memories: Rovee-Collier's Kick Studies

- *Mobile conjugate reinforcement paradigm* - Tying ribbon to baby's ankle, measure baseline kick activity, learning phase where baby finds that kicking will move the mobile; retrieval: seeing how long it will take the baby to figure out their kicks won't move the mobile once the apparatus is modified - Retention in 2-month olds for 2 days - Retention in 3-month olds for at least a week (reminder seems to reactivate memory, and it increases the life of a memory if it's presented within a "time window") - Retention in 6-month olds for 18 months with one reminder!