Memory Notes

HISTORY OF COGNITIVE DEVELOPMENT RESEARCH

Researchers need to have contextual research ie know what adult standards are to compare development to

Piaget – Stage Theory

Emphasis on qualitative changes in children’s capabilities and mental operations: what they can vs cannot do at each stage

Most contemporary research takes an info processing approach: breaking down the task the child is trying to solve into its elements, understanding it as a computational problem

Emphasis on:

Quantitative changes

Task demands: check that failures in something complex are no due to something more basic eg limited memory capacity

failed to provide context relative to adult standards = limitation

2 of Piaget’s influential findings

OBJECT PERMANENCE

Children below about 8 months do not search for a hidden object

‘Out of sight, out of mind’ for infants when the object is hidden it no longer exists

More recent studies show evidence that much younger infants do keep track of hidden objects, when performance demands are reduced

Measure looking behaviour instead of searching responses

Spelke, 1996

Screen acts as drawbridge

Habituated to drawbridge moving back and forth

Box placed behind screen

Possible event: box stops the drawbridge going back

Impossible event: drawbridge STILL goes back

5 m/o look longer at the impossible event

shows they can remember the box exists even when it is not there

THE ‘A NOT B’ ERROR (to about 10 months)

Experimenter hides object in A in front of child

Child has to fetch object task repeated until child succeeds in looking in A

THEN experimenter hides it in B

Children often still look in A even though they saw it hidden in B

But looking time studies show that much younger infants keep track of where hidden objects are

Many alternative accounts of the AB error based on specific cognitive abilities, including memory, inhibition, motor control

Piaget and others on early memory

Piaget (1952) – children under 18 months incapable of mentally representing objects and events, live in a ‘here and now’ world

Pillemer & White, 1989: ‘infantile amnesia’

BUT once specialised methods were developed to assess early memories, research showed infants to have similar kinds of memory abilities to adults

suggests that the major development changes are quantitative (capacity, duration)

MEMORY

Semantic memory: all the world knowledge and facts a person possesses

Episodic memory: memory for specific events, often autobiographical

Multiple memory systems:

Dissociable in their functional properties and neural bases (from patients, imaging studies, animal studies)

Development of infant LTM

Rovee-Collier, 1999:

1^st year and a half:

• Duration of memory increases

• Specificity of the cues required for recognition decrease after short test delays

• Latency of priming progressively decreases to adult level

Memory dissociations of very young infants on recognition and priming tasks are identical to adults

suggests both memory systems are present very early in development instead of emerging hierarchically over the 1^st year

Young infants can remember an event over the entire ‘infantile amnesia’ period if periodically exposed to nonverbal reminders

The same mechanisms appear to underlie memory processing in infants and adults

Werner & Siqueland, 1978: newborns could remember a previously seen visual event over 24-hours

altered their sucking patterns when colour/pattern changed

Newborns can remember speech sounds over 24 hours:

Mothers repeated 2 words ‘tinder’ and ‘beguile’ to their 14w/o babies 60 times a day for 13 days

At 14 and 28 hours after training infants remembered the words and recognised them better than their own names

Rovee-Collier, 1999:

Mobile task for 2-6m/o:

Infants learn that kicking makes the mobile move via a ribbon attached to their leg. Do they remember?

Experiment: test again with trained vs novel mobile

Used to measure properties of infant memory

Baseline = rate at which they kick before the ankle ribbon is connected to the mobile

• 3m/o remember after 2 week delay

• Max length of retention increases linearly with age

• But having more training sessions can extend the retention interval even at younger ages

Train task for 6-18m/o:

Learn to move a small train around a track by depressing a lever

Results:

Infants trained in either task

They show retention after short delays

Duration of retention increases with age

Performance is influenced by levels of training remember for much longer is given shorter but more frequent training sessions instead of longer but less training sessions

Deferred-imitation paradigm: to test nonverbal recall:

Infants watch an adult manipulate an object and are asked to imitate later

6m/o who watch for 30s imitate if tested immediately after but not 24hours later

6m/o who watch for 60s can imitate 24hours later

= form of explicit memory

Older age = longer recall

More repetitions = longer recall

Also: importance of ‘post-encoding’ processes (consolidation)

Developmental changes in priming latency

Even if infants cannot recognise a stimulus, they can still respond to it if they are exposed to a memory prime (prompt) before retention tests

Eg being shown the original mobile allows a perceptual identification process retrieval of the latent memory by increases its accessibility

Hildreth & Rovee-Collier, 1999:

Primed memories infants forgot and assessed how long it took for recovery of these memories

3-12m/o were trained in the mobile/train task and primed once they no longer recognised it

The time it took infants to forget the training even increased with age

Latency of priming decreased over the same period until at 12m/o they responded instantly to the prime

speed of processing increases over the 1^st year

even at 3m/o, infants respond instantly if a prime is shown if the memory was recently acquired

Development of LTM: episodic memory

‘Infantile amnesia’?

Most adults have few memories of events below age 3

From 3-7 years adults have fewer memories than would be...

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