Transcript Health, Nutrition and Feeding

Cognitive Development in
Infancy
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New term definitions
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Early Term: Between 37 weeks 0 days and
38 weeks 6 days
Full Term: Between 39 weeks 0 days and
40 weeks 6 days
Late Term: Between 41 weeks 0 days and
41 weeks 6 days
Postterm: Between 42 weeks 0 days and
beyond
Dr. Jeffrey L. Ecker, chair of the American
College of Obstetricians and Gynecologists’ 4
Questions
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Describe different “developmental job
descriptions” of early infancy
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Describe different mechanisms of learning in infancy
Indicate two infant predictors of adolescent’s
intelligence
Does rapidity of habituation predict future
intelligence? Why do you think so?
What are the strengths and limitations of the
habituation paradigm?
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Video resources
• Rovee-collier, infant brains, visual cliff, habituation
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Developmental job descriptions
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Body-Builder (O-9 weeks).
Inventory Control Officer (10-24 weeks)
Map Maker, Level I (25-40 weeks)
Map Maker, Level II (41-52 weeks)
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Rovee-Collier, 1996, “Shifting the focus from
what to why” Infant Behavior and Development
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Body-Builder (O-9 weeks)
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What I do and need
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Part-time work days and nights acquiring energy and
minimizing energy expenditure. Variable hours.
Persistence required; strong suck and cry desirable.
Net energy income will be invested in fueling growth.
Around-the-clock protection and personal shopper
service available.
Practical implications
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Great at sucking and looking to control environment
But kicking requires too much energy
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Inventory Control Officer
(10-24 weeks)
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What I do and need
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Full-time days/occasional nights maintaining and
controlling inventory of people and objects, what goes
with what, and what happens when and in what order.
Must be adept at soliciting caregiving and social
interactions. Regular hours, benefits.
Practical implications
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Can kick to show sophisticated memory for events and
objects
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Experimental example
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An infant’s foot was attached to a mobile.
Initially, the infant would kick just by chance.
Each kick followed by the mobile’s movement.
This movement was interesting to the infant, and
reinforced the kicking behavior,
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increasing the likelihood that the infant would kick
again.
Video
Real life example: https://www.youtube.com/watch?v=lPJiB-oGMN0
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Map Maker positions
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Level I (25-40 weeks)
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Full-time days, weekends; no nights. Regular hours.
Acquisition of preliminary cognitive map; some
babbling, receptive language skills desired.
Beginning-level crawling a must.
Level II (41-52 weeks)
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Full-time days, weekends, no nights.
Regular hours. Self-starter. Navigational and receptive
language skills required.
Must know when who and what are where, and how to
get there.
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Rovee-Collier, 1996, Shifting the focus from what to why
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Visual cliff and social
information processing
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A parent’s smiling face will convince an
infant to cross over the visual cliff before
they have begun to crawl—social
referencing.
Visual Cliff
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The Epigenesis of Wariness of Heights
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Human infants with no crawling experience show
no wariness of heights, but wariness becomes
strong over the life span.
The crucial component of locomotor experience in
this emotional change is developments in visual
proprioception—the optically based perception of
self-movement.
Precrawling infants randomly assigned to drive a
powered mobility device showed significantly
greater visual proprioception, and significantly
greater wariness of heights, than did controls.
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Basic learning mechanisms
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Classical Conditioning
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Operant Conditioning
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infant responds to a stimulus
Infant action changes the likelihood that an
action will occur.
Habituation and Dishabituation
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http://www.cogs.susx.ac.uk/users/alisonp/dev1/lecture
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Classical Conditioning
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With repeated pairings of neutral stimulus and
unconditioned stimulus, the infant begins to
respond to the neutral stimulus.
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Classical conditioning helps infants understand
which events “go together,” to anticipate what
happens next.
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The neutral stimulus is referred to as a conditioned
stimulus, and the response as a conditioned response.
Helps them learn to make sense of their environment.
Classical conditioning of reflexes
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Classical conditioning at one month
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Sleeping infants presented with 'social'
(voice) or non-social stimulus (eg backward
voice) followed by an airpuff to the eyelid.
Infants increased learning across trials,
regardless of stimulus type.
Infants conditioned to the 'social' stimulus
showed increased learning compared to
infants conditioned the non-social stimuli.
Reeb‐Sutherland, B. C., Fifer, W. P., Byrd, D. L., Hammock, E. A. D., Levitt, P., & Fox, N. A. (2011).
One‐month‐old human infants learn about the social world while they sleep.
Developmental Science, 14(5), 1134-1141. doi: 10.1111/j.1467-7687.2011.01062.x
Operant conditioning
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A behavior followed by a stimulus that changes
the likelihood of the behavior occurring again.
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A stimulus that makes a behavior more likely to occur
again is a reinforcer. Two kinds of reinforcers:
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presentation of a desired stimulus
removal of an unpleasant stimulus.
A stimulus that makes a behavior less likely to occur
again is called punishment.
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Two kinds of punishment:
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removal of a desired stimulus
presentation of an unpleasant stimulus.
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Operant conditioning in research
on infant perception
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Using operant conditioning, researchers can
“teach” infants to respond to a stimulus.
By varying the stimulus slightly, researchers can
see whether infants perceive the variation.
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To discover which stimuli infants are able to perceive,
and which stimuli infants prefer.
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Infants have a limited repertoire of responses--studies usually
use sucking or head turn as the behavior which is reinforced.
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Examples: operant conditioning
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A pacifier with which infants controlled, by
sucking or stopping sucking, whether they heard
the mother’s voice or another woman’s voice.
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Allowed the researchers to determine that infants were
capable of perceiving the difference between the voices.
Testing infant hearing
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Infants trained to turn their heads in response to a sound
Head turning is reinforced by the sight of toys which
light up and become active when the infant turns.
The sound is then produced more and more quietly, to
determine what sounds the infant is able to perceive.
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Operant conditioning in
development
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When infants smile or vocalize, parents often
respond by smiling or vocalizing in return.
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The parent’s response may reinforce the infant,
increasing the likelihood that the behavior will recur.
Parents can be operant conditioned by their infants
as well.
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When a parent is effective in soothing a crying infant,
the infant stops crying.
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This removal of an unpleasant stimulus (crying) reinforces the
parent’s soothing technique, and the parent is more likely to
use the same technique the next time the infant cries.
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Operant conditioning in robotics?
“A new approach to reinforcement
learning for control problems which
combines value-function
approximation with linear
architectures and approximate policy
iteration.” Lagoudakis & Parr, 2003
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More complex rewards…
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http://www.sciencedirect.com/science?_ob=ArticleURL&_
“use the reduction of uncertainty (information
gain) as a reward signal. The result is an
interesting form of learning in which the
learner rewards itself for conducting actions
that help reduce its own sense of uncertainty”
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Stimulus
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This pattern
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Was presented to 93 premature infants for 60 sec.
Infants who gazed at the pattern for more time had
lower intelligence at 18 years if age.
Infants who gazed at the pattern for less time had
higher intelligence
Fixation duration in infancy and score on the
intelligence test, r(91) = -.36, p < .0002.
Why?
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Why does Infant Attention Predict
Intelligence?
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Three Theories
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Speed or efficiency of information processing
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Inhibition of responses to uninformative/familiar
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Sigman et al., 1991
Fixation taps processing
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Sigman, Cohen, Beckwith, 1997
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18 Year IQ Depends on Infant Attention
and Caregiver Behavior
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What conditions predict
intelligence?
Inexact
rendition
of Sigman,
Cohen, &
Beckwith
(1997)
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90
N=25
N=24
N=22
N=20
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Long Infant Long Infant Short Infant Short Infant
Fixation /
Fixation /
Fixation /
Fixation /
Low Maternal High Maternal Low Maternal High Maternal
Vocalization Vocalization Vocalization Vocalization
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Maternal vocalization
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More maternal vocalizing at 1 month
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Also predicts greater adolescent intelligence
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Associated with vocalizations at 8 & 24 months
and with socioeconomic status
R2 = .22 for gazing and maternal vocalizations
Infants who gaze briefly and who were
vocalized to more show especially high
intelligence.
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Interaction effect
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Infant habituation child intelligence
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‘Habituation and recognition memory in first year
of life predict IQ between 1 and 8 years
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Weighted (for N) mean correlation of .36
Raw median correlation of .45.
Similar for habituation & recognition memory.
Predictions consistently higher than for standardized
infant tests of general development for nonrisk but not
for risk samples.
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For nonrisk samples, predictions not consistently higher than
predicting from parental education and socioeconomic status!
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A Meta-Analysis of Infant Habituation and Recognition Memory Performance as
Predictors of Later IQ Robert B. McCall, Michael S. Carriger Child Development, Vol.
64, No. 1 (Feb., 1993), pp. 57-79
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Habituation as a measure of
cognitive function?
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A measure of learning and memory:
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habituation implies that the infant has encoded some of
its properties & retained them.
Habituation rate is linked to later achievement.
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Individual differences in speed of habituation relates to
later IQ scores (Fagan & Singer, 1983).
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www.cogs.susx.ac.uk/users/alisonp/dev1/lecture2.html
Bored faster  Brighter??
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Bored faster  Brighter??
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http://www.youtube.com/watch?v=dlilZh60qdA from 1:30
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Habituation and dishabituation
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Habituation - gradual reduction in the strength of a
response as the result of repetitive stimulation.
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When infants look at one stimulus for long period, they
habituate, and look away more rapidly.
Dishabituation occurs when a new stimulus is
presented, infants look at new stimulus longer
Enables infants to pay attention to new stimuli
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Gene x SES & Mental Ability (MA)
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SES-related disparities in MA
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General contribution of genes & environment
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SES differences increase from 10mos to 2yrs
Heritability higher at age 2
SES interacts with genes & environment
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SES moderates genetic contribution to MA change
Increasing heritability of MA in infancy most
evident for high SES
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Tucker-Drob, E. M., Rhemtulla, M., Harden, K. P., Turkheimer, E., & Fask, D. (2011). Emergence of a Gene
× Socioeconomic Status Interaction on Infant Mental Ability Between 10 Months and 2 Years. Psychological
Science, 22(1), 125-133.
Fernandez
Effect of genes on mental
ability increases over infant
development in high SES
case (Tucker-Drob, et al.. (2011)
Fernandez
Fagan Test of Infant Intelligence
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Assesses cognitive development in infancy.
Composed of habituation-dishabituation items.
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“a “novelty score” -- amount of fixation during the test
phase devoted to the novel picture divided by the total
fixation time to both the novel and familiar picture.”
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http://infantest.com/ftii.pdf
Used for research studies—index of the relative
level of functioning in group being studied
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Does not determine an individual child’s performance
relative to that of the children in the norming sample –
like in the Bayley
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Difficulties in assessing cognitive
development in infancy
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Infants may become distracted, tired, or
bored.
It’s hard to motivate infants to perform at
their best.
Interpretation of measurable dependent
variables (e.g., looking time) is key
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Normed assessments of cognitive
development in infancy
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Research
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Exposure differences, prematurity differences
Identification of infants at risk for
developmental delay in order to provide
early intervention services.
Scaled scores used at every age
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Bayley Scales of Infant
Development II (1993)
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Permits observation of concepts noted by Piaget:
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A not B search error
intentional, goal-directed behavior.
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performance is compared with large group of infants on whom
the test was normed.
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Applied developmental research
1 through 3 ½ years
Extensively normed
Basis for early referral
Test-retest reliability
blue puzzle
http://www.youtube.com/watch?v=kpx4AgO-Oxw&feature=relmfu yellow pegs
http://www.youtube.com/watch?v=y1-ANMq1Cwo&feature=relmfu doll
http://www.youtube.com/watch?v=76SRamqYn0A&feature=related
Mullen Scales are
alternate assessment
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What’s on the test?
A series of difficulty-graded items
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One Year
– Mental
n Making speech sounds and
words
n Fitting a piece in puzzle
n Basic motor tasks
– Motor
n Standing, walking, &
throwing
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Two & three year
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Mental
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Uses multiple words in
phrases
Completing puzzle
Counting & concepts
Motor
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Runs, jumps, copies
shapes
Cognitive performance becomes more verbal.
Children have to make verbal responses and
understand more complex verbal instructions
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