Instructor: Sean Kang, Ph.D.
Email: [email protected]
Class Meets: Weekdays 1:30-4:00pm @ 9B114
What do infants remember about their recent past?
SKKU ISS3147
Myths and Mysteries of
Human Learning and Memory
Memory in Children
(How might one study this question?)
What do children remember about their recent
past?
How does memory develop with age?
What do adults remember about their infancy /
childhood?
13 Jul 2016
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Let’s start at the beginning:
What do infants remember about their past?
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Infants are curious about novel aspects of their
environment. 3 basic techniques for studying
memory in preverbal infants capitalise on this:
If we want to find out more about the memory of an 8month-old, what can we do? (One challenge: Infants are
either pre-verbal or have very limited language abilities…
i.e., do not understand instructions, can’t say/write
answers)
1. Visual/auditory preferences
•
•
Habituation
Paired-comparison
2. Conditioning
The solution: Capitalise on the things infants can do!
3. Deferred imitation
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Habituation
Paired-Comparison
• Stimulus is repeatedly presented until infant’s attention
to it (looking/fixation time) declines to some
absolute/relative level… habituation
• Then, different stimulus is presented to half the subjects,
while original stimulus presented to remaining subjects.
Retention is inferred from increased responding
(looking/fixation time) to the novel stimulus relative to the
original one. If dishabituation occurs, evidence that the
infant has memory for the earlier stimulus.
• Infant first familiarised with a
particular stimulus.
• Then at test, infant is
simultaneously presented with
the previously exposed
stimulus and a novel stimulus.
• Retention is inferred if the
infant looks at / fixates on the
novel stimulus > 50% of the
time (infants who never saw
the original stimulus should
fixate on both test stimuli
equally).
Retention interval
time
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Non-nutritive nipple
• Dependent variable (i.e., what’s
measured): sucking rate
• DeCasper and Spence (1986) asked
women to recite aloud a story (e.g., Dr
Seuss’s The Cat in the Hat) twice daily
during the last 6 weeks of pregnancy.
• ~56 hours after birth, infants could
successively listen to a recording of the
pre-exposed passage (i.e., the same
passage that was heard in utero) or a
novel one by sucking on a non-nutritive
nipple that controlled the tape recorder.
• Infants had a preference for the preexposed passage (control infants
displayed no preference).
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The novelty preference apparatus used in
the paired-comparison procedure. The
direction and duration of looking at the
familiar and novel targets are recorded via
a midline peephole. On the preceding trial,
the familiar pattern was displayed on both
panels.
Infants are curious about novel aspects of their
environment. 3 basic techniques for studying
memory in preverbal infants capitalise on this:
1. Visual preferences
•
•
Habituation
Paired-comparison
2. Conditioning
3. Deferred imitation
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(a) Training:
(b) Baseline and at test:
Mobile task
Carolyn Rovee-Collier recalls the moment as if it happened
yesterday. The year was 1965, a frantic time for a new mother
studying for her Brown doctoral exams. Trying to balance
books and baby, Rovee-Collier noticed that Benjamin, eight
weeks old, was calmest when she shook a small mobile over
his head. “My grandmother once told me that if you could
harness the energy of a two-year-old, you could turn all the
windmills in Holland,” she recalls. “So I thought, ‘Why don’t I
let him do it?’”
Taking a cloth tie from around her waist, the young researcher
bound one of Benjamin’s feet to the mobile, then returned to
cramming. Or tried to. “From where I was working, I could
hear his leg hitting the mattress: ‘boom, boom, boom,’” she
says. The sound drew her attention and eventually led to an
observation that would rock the world of infant psychology.
“Every expert in the field said that babies couldn’t learn at this
age,” she says, “and yet in a matter of minutes Benjamin had
figured out how to move this mobile.”
A 3-month-old during
training in the mobile task
and during a retention test.
During training (a), the
infant’s kicks move the
mobile by means of the
ankle ribbon that is
connected to the mobile
hook. During baseline and
all retention tests (b), the
ankle ribbon and the mobile
are connected to different
hooks so that kicks cannot
move the mobile.
Carolyn
Rovee-Collier
At test, if infants recognise the mobile, they will kick above their baseline
rate.
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(Rovee-Collier, 1999)
Train task (more age-appropriate for infants > 6 months)
Infants are curious about novel aspects of their
environment. 3 basic techniques for studying
memory in preverbal infants capitalise on this:
1. Visual preferences
•
•
Habituation
Paired-comparison
2. Conditioning
3. Deferred imitation
In the train task, infants learn to move a miniature train around a
circular track by pressing a lever (each press moves the train for 1 or 2 s).
During baseline and the retention test, the lever is deactivated (presses do
not move the train); infants who recognise the train respond above their
baseline rate.
(Rovee-Collier, 1999)
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Puppet task (deferred imitation)
(Meltzoff &
Moore, 1977)
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Infants (6 months and older) first watch an experimenter remove a mitten
from a puppet’s hand and ring a bell hidden inside. Then after some
delay, the puppet is presented to the infant again to see if s/he will imitate
the earlier actions of the experimenter.
(Barr, Dowden, & Hayne, 1996)
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With increasing age, infants exhibit retention after progressively
longer delays:
Maximum duration of retention (in weeks) of infants who were trained and tested
in the operant mobile and train tasks and the deferred imitation (puppet) task
using a standardised procedure with age-calibrated parameters.
Age-related changes in forgetting…
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(Rovee-Collier & Cuevas, 2009)
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How specific is the memory?
Memory development in the early years
What develops?
Focal cue at test
– 2- to 6-month-olds do not generalise to a novel mobile or train
(Hartshorn et al., 1998); 6- and 12-month-olds do not display
deferred imitation when puppet is changed (Hayne et al., 2000).
– With increasing age, infants generalise to novel test cues
(initially after short test delays, and later after progressively
longer ones).
• Brain (frontal lobes, hippocampus)
• Strategy use
• Task-relevant knowledge
• Metamemory (knowledge & beliefs about own memory)
Context
– The context at training and at test can affect retention. E.g., in
the mobile task, 3-month-olds tested in a different crib liner 5
days after acquisition did not show retention (Butler & RoveeCollier, 1989).
– With longer delays, a change in context tends to impair retention.
• Speed
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Development of Strategies
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Development of Strategies
• Younger children: exact (rote) rehearsal, often just 1 item
at a time
• Older children / adolescents: modify to fit material /
organise / elaborative rehearsal
– E.g., if asked to remember: apple, bicycle, house, bear, cheese,
lion, apartment, tiger, carrot, car, hotel, bus…
– Output order during recall will often show signs of clustering /
organisation by semantic category
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% of subjects who rehearsed
during the retention interval
• Probably linked to frontal lobe development
• (Spontaneous) rehearsal emerges ~ age 6 or 7 years.
(Flavell, Beach, & Chinsky, 1966)
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Development of Task-Relevant Knowledge
Development of Metamemory
Build-up of semantic networks
Learning schemas
Although 5-year-olds know that it is easier to remember a
short list of words than a long list or to remember
something that occurred recently than a long time ago,
they still have underdeveloped metamemory.
Can lead to distortions, though…
E.g., DRM paradigm: Higher false recall and recognition of
the critical lure for older than younger children
E.g., If 5- and 8-year-olds are given as much time as they
want to learn a list of words for an upcoming test, the 5year-olds will typically declare that they’ve learned them
all after a quick glance. The 8-year-olds, however, will
know that more time is needed to study the words.
(Brainerd &
Reyna, 2004)
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Speed: Consider the Word Length Effect
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What is your earliest childhood memory?
What age were you at the time of the event?
Word Span
Some common examples: Visit to amusement park, playing
at playground, birthday party, family gathering, family
vacation, interaction with sibling(s) or mom.
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Why can’t adults recall memories from
infancy/very early childhood?
Children as eyewitnesses
Children, esp. young children, are highly susceptible to
suggestion. In 1900, Alfred Binet published La Suggestibilité,
describing his research on the effects of suggestion in children.
i.e., Infantile amnesia.
And yet 4-yr-old children are able to recall events that
occurred when they were < 2.5 yrs of age (Fivush &
Hamond, 1990).
Possible causes:
– Immaturity of the brain
– Limited verbal abilities prevents rehearsal
– Contextual details of very early memories are lost, and so while
adults may be able to remember early-life events, they can’t
pinpoint their origins; or very early memories have been modified
many times, their origins are impossible to identify
– Encoding context for very early memories are very different (cf.
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the present), reducing the probability of successful retrieval
The McMartin Preschool Trial
(Bruck & Ceci, 1997)
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The McMartin Preschool Trial
Hundreds of the preschool students were then
interviewed by the Children’s Institute
International, an abuse therapy clinic in LA.
Interviewing techniques used were highly
suggestive, invited children to pretend or
speculate about events.
In 1983, Judy Johnson made a police report that
her son had been sodomised by his teacher at a
Manhattan Beach (CA) preschool run by the
McMartins.
Police sent a letter to 200 parents of students at
the school, stating that their children might have
been abused:
“…Please question your child to see if he or she has been a witness to any
crime or if he or she has been a victim. Our investigation indicates that possible
criminal acts include: oral sex, fondling of genitals, buttock or chest area, and
sodomy, possibly committed under the pretense of "taking the child's
temperature." Also photos may have been taken of children without their
clothing. Any information from your child regarding having ever observed Ray
Buckey to leave a classroom alone with a child during any nap period, or if they
have ever observed Ray Buckey tie up a child, is important….”
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360 children claimed to have been abused. 41
testified during the grand jury and pre-trial
hearings. Less than a dozen testified at the
actual trial.
In 1984, 7 preschool staff members were
eventually charged with 321 counts of child
abuse involving 48 children.
By 1990, the defendents were either acquitted or
had the charges dismissed. The trial lasted 7
years and cost over $15 million.
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The McMartin Preschool Trial
The McMartin Preschool Trial
Post-trial analysis of videotapes of the (child) interviews revealed:
• Suggestive questions
Post-trial analysis of videotapes of the (child) interviews revealed:
• Negative consequences (disapproval)
– “Can you remember the naked pictures?” (when no picture taking/nudity
had been mentioned by the child)
– When a child denied any wrongdoing by the McMartin teachers, the interviewer
responded: “Are you going to be stupid, or are you going to be smart and help us
here?”
• “Other people” strategy (i.e., telling the child that information had
already been obtained from other children regarding the topic of the
interview; exerts pressure towards conformity)
• Repeated questioning (ask-and-answered)
– “We know about the [Naked Movie Star] game cause we just have had…
twenty kids told us about that game… Do you think if I ask you a question,
you could put your thinking cap on and you might remember?”
• Positive consequences (praises, approval)
– After a series of suggestive questions, one child agreed that a teacher took
naked photos of children. The interviewer responded: “Can I pat you on the
head… look at what a good help you can be. You’re going to help all these
little children just because you’re so smart!”
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(Garven, Wood, Malpass, & Shaw, 1998)
I: Can you remember the naked pictures?
C: (Shakes head "no")
I: Can't remember that part?
C: (Shakes head "no")
I: Why don't you think about that for a while, okay? Your memory might come
back to you.
• Inviting speculation
Often used when other techniques had failed to elicit an allegation of wrongdoing
from the child. Children were urged to speculate: "Let‘s figure out what
happened," "What do you think happened?” or "Let's pretend and see what might
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have happened."
(Garven, Wood, Malpass, & Shaw, 1998)
Summary
To study memory in pre-verbal infants, we have to
capitalise on some of the things they naturally do
(e.g., suck, look, kick) and the fact that infants
generally prefer novel stimuli.
Abstract
The belief that props help children report abuse has fostered the widespread
use of anatomical dolls and body diagrams in forensic interviews. Yet studies
involving alleged abuse victims, children who have experienced medical
examinations, and children who have participated in staged events have failed
to find consistent evidence that props improve young children’s ability to report
key information related to bodily contact. Because props elevate the risk of
erroneous touch reports, interviewers need to reconsider the belief that props
are developmentally appropriate in forensic interviews, and researchers need
to explore new approaches for eliciting disclosures of inappropriate touching.
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Large memory-related developments occur within the
first few years of life, including anatomical
development, strategy use, speed of processing.
Infantile amnesia offset: ~3-4 yrs of age.
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