Cognitive Development in Infancy

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New term definitions

Early Term: Between 37 weeks 0 days and 38 weeks 6 daysFull Term: Between 39 weeks 0 days and 40 weeks 6 daysLate Term: Between 41 weeks 0 days and 41 weeks 6 daysPostterm: Between 42 weeks 0 days and beyond

Dr. Jeffrey L. Ecker, chair of the American College of Obstetricians and Gynecologists’ (ACOG) Committee on Obstetric Practice. ACOG, and the Society for Maternal-Fetal Medicine (SMFM) wrote the joint opinion paper published in the journal Obstetrics & Gynecology.

Read more: New (And Hopefully Improved) Definition of Term Pregnancy | TIME.com http://healthland.time.com/2013/10/22/new-and-hopefully-improved-definition-of-term-pregnancy/#ixzz2lI5RyHJt

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Questions

Describe different “developmental job descriptions” of early infancy

– 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?– Video resources

• Rovee-collier, infant brains, visual cliff, habituation

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Developmental job descriptions

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)

– Rovee-Collier, 1996, “Shifting the focus from what to why” Infant Behavior and Development

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Body-Builder (O-9 weeks)

What I do and need– 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

– Great at sucking and looking to control environment– But kicking requires too much energy

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Inventory Control Officer (10-24 weeks) What I do and need

– 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– Can kick to show sophisticated memory for events and

objects

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Experimental example

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, – 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

Level I (25-40 weeks)– 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) – 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.• Rovee-Collier, 1996, Shifting the focus from what to why

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Visual cliff and social information processing 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

The Epigenesis of Wariness of Heights

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

Classical Conditioning– infant responds to a stimulus

Operant Conditioning– Infant action changes the likelihood that an

action will occur. Habituation and Dishabituation

• http://www.cogs.susx.ac.uk/users/alisonp/dev1/lecture2.html

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Classical Conditioning

With repeated pairings of neutral stimulus and unconditioned stimulus, the infant begins to respond to the neutral stimulus. – The neutral stimulus is referred to as a conditioned

stimulus, and the response as a conditioned response. Classical conditioning helps infants understand

which events “go together,” to anticipate what happens next. – Helps them learn to make sense of their environment.

Classical conditioning of reflexes

Classical conditioning at one month

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

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Operant conditioning

A behavior followed by a stimulus that changes the likelihood of the behavior occurring again. – A stimulus that makes a behavior more likely to occur

again is a reinforcer. Two kinds of reinforcers: presentation of a desired stimulus removal of an unpleasant stimulus.

– A stimulus that makes a behavior less likely to occur again is called punishment.

Two kinds of punishment: – removal of a desired stimulus – presentation of an unpleasant stimulus.

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Operant conditioning in research on infant perception 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.– To discover which stimuli infants are able to perceive,

and which stimuli infants prefer. 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

A pacifier with which infants controlled, by sucking or stopping sucking, whether they heard the mother’s voice or another woman’s voice.

– Allowed the researchers to determine that infants were capable of perceiving the difference between the voices.

Testing infant hearing – 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 When infants smile or vocalize, parents often

respond by smiling or vocalizing in return. – 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.– When a parent is effective in soothing a crying infant,

the infant stops crying. 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.

Operant conditioning in robotics?

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“A new approach to reinforcement learning for control problems which

combines value-function approximation with linear

architectures and approximate policy iteration.” Lagoudakis & Parr, 2003

 

More complex rewards… http://www.sciencedirect.com/science?_ob=ArticleURL&_

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“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

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?

Why does Infant Attention Predict Intelligence?

Three Theories– Speed or efficiency of information processing

Inhibition of responses to uninformative/familiar– Sigman et al., 1991

– Fixation taps processing Sigman, Cohen, Beckwith, 1997

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Long InfantFixation /

Low MaternalVocalization

Long InfantFixation /

High MaternalVocalization

Short InfantFixation /

Low MaternalVocalization

Short InfantFixation /

High MaternalVocalization

N=25 N=24 N=22 N=20

18 Year IQ Depends on Infant Attention and Caregiver Behavior

Inexact rendition of Sigman,Cohen, & Beckwith (1997)

What conditions predict intelligence?

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Maternal vocalization

More maternal vocalizing at 1 month Associated with vocalizations at 8 & 24 months

and with socioeconomic status Also predicts greater adolescent intelligence

R2 = .22 for gazing and maternal vocalizations Infants who gaze briefly and who were

vocalized to more show especially high intelligence. Interaction effect

Infant habituation child intelligence

‘Habituation and recognition memory in first year of life predict IQ between 1 and 8 years

– 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.

For nonrisk samples, predictions not consistently higher than predicting from parental education and socioeconomic status!

• 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? A measure of learning and memory:

– habituation implies that the infant has encoded some of its properties & retained them.

Habituation rate is linked to later achievement. – Individual differences in speed of habituation relates to

later IQ scores (Fagan & Singer, 1983).• www.cogs.susx.ac.uk/users/alisonp/dev1/lecture2.html

Bored faster Brighter??

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Bored faster Brighter??

• http://www.youtube.com/watch?v=dlilZh60qdA from 1:30

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Habituation and dishabituation

Habituation - gradual reduction in the strength of a response as the result of repetitive stimulation. – 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

Gene x SES & Mental Ability (MA)

1. SES-related disparities in MA– SES differences increase from 10mos to 2yrs

2. General contribution of genes & environment – Heritability higher at age 2

3. SES interacts with genes & environment– SES moderates genetic contribution to MA change – Increasing heritability of MA in infancy most evident for

high SES 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

Fernandez

Effect of genes on mental ability increases over infant development in high SES case (Tucker-Drob, et al.. (2011)

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Fagan Test of Infant Intelligence

Assesses cognitive development in infancy. Composed of habituation-dishabituation items.

– “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.”

http://infantest.com/ftii.pdf

Used for research studies—index of the relative level of functioning in group being studied

– 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 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 Research

– 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) Permits observation of concepts noted by Piaget:

– A not B search error– intentional, goal-directed behavior.

performance is compared with large group of infants on whom the test was normed.

• Applied developmental research• 1 through 3 ½ years • Extensively normed• Basis for early referral • Test-retest reliability

http://www.youtube.com/watch?v=76SRamqYn0A&feature=related 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

Mullen Scales are alternate assessment

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What’s on the test? A series of difficulty-graded items

One Year– Mental

Making speech sounds and words

Fitting a piece in puzzle Basic motor tasks

– Motor Standing, walking, &

throwing

Two & three year– Mental

Uses multiple words in phrases

Completing puzzle Counting & concepts

– Motor Runs, jumps, copies

shapes

Cognitive performance becomes more verbal.Children have to make verbal responses and understand more complex verbal instructions