Infant Capacities and the Process of Change

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Infant Capacities and the Process of Change

• The Development of Children (5th ed.)
• Cole, Cole Lightfoot
• Chapter 4

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What does this mean?

• Babies control and bring up their families as
  much as they are controlled by them in fact, we
  may say that the family brings up a baby by being
  brought up by him.

Erik Erikson in Childhood and Society
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Why is this the case?

• Compared with many animals that are able to
  negotiate their environments at birth almost as
  well as their parents, human beings are born in a
  state of marked immaturity. For many years,
  human offspring must depend on their parents and
  other adults for their survival.

Cole, Cole Lightfoot, p. 114
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Overview of the Journey

• Brain development
• Earliest capacities
• Coordination with the social world
• Mechanisms of development
• First postnatal BSB shift

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Brain Development

• Neurons and Neural Networks
• Experience and Development
• The CNS and the Brain

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At birth, the brain has all the cells it will
have, yet it is ¼ the size of an adult brain. Why?

1. Dendrite size and branching
2. Axon branching and myelination (speed)

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Neural Networks in Postnatal Life
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Experience and Development
Synapticpruning
Exuberant synapto-genesis
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Rats Raised in Enriched Environments

• Increased rates of learning in standard
  laboratory tasks, such as learning a maze
• Increased overall weight of the cerebral cortex
  (the part of the brain that integrates sensory
  information)
• Increased amounts of acetylcholinesterase, a
  brain enzyme that enhances learning
• Larger neuronal cell bodies and glial cells
  (which provide insulation, support and nutrients
  to neuronal cells)
• More synaptic connections

Rosenzweig, 1984
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Active Interaction with the Environment

• Rats were raised with an enriched environment but
  were housed singly in small cages so that could
  do no more than observe what was going on around
  them
• The learning capacity of these rats differed in
  no way from that of the animals that were housed
  in individual cages away from the enriched
  environment
• What might this imply for child-rearing? For
  teaching?

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Brain Elements and Functions
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Six Mammalian Species
Why the difference?
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Cortex Development

• Matures later than the lower-lying areas of the
  CNS, spinal cord, brain stem
• Primary motor area
• First area of the cortex to develop
• Responsible for voluntary (nonreflexive) movement
• Begins with raising head (1 month), control of
  arms and trunk (3 months) leg control is last to
  develop
• Primary sensory areas
• Begins with touch, then visual, then auditory
• By 3 months, all primary sensory areas are
  relatively mature
• Frontal cortex (e.g., planning, decision-making)
• Begins to function in infancy but continues to
  develop throughout childhood

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Earliest Capacities

• Sensory Processes
• Response Processes

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Sensory Processes

• Normal full-term newborns enter the world with
  all sensory systems functioning, but not all of
  these systems have developed to the same level
  due to different developmental rates (i.e.,
  heterochrony)
• Indications of sensation
• Turning of the head, variation in brain waves,
  changes in rate of sucking on a nipple
• Habituation Becomes bored and stops attending
• Dishabituation Interest is renewed after the
  infant perceives a change in the stimulus

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Hearing

• Infants only minutes old will startle with a loud
  noise and may even cry
• Will also turn their heads toward the source of
  a noise

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Hearing

• Infants can distinguish the sound of the human
  voice from other kinds of sounds, and seem to
  prefer it
• Are particularly interested in speech with the
  high pitch and slow, exaggerated pronun-ciation
  (i.e., baby talk)
• Evidence that by 2 days old, some babies would
  rather hear the language that has been spoken
  around them than a foreign language

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Hearing Capacity

• At 2 months of age
• Present phoneme (e.g., /pa/)
• Habituate (i.e., return to baseline sucking rate)
• New phoneme(e.b., /ba/)
• Dishabituate (i.e., sucking rate increases)

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New Consonant

• Both groups hear a consonant sound
• Habituate
• Experimental group hears a new consonant sound at
  time marked 0
• Infants are able to distinguish consonant sounds

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Auditory Discrimination and Culture

• Infants can distinguish among language sounds
  that do not occur in their native language, but
  this capacity diminishes during the first year of
  life.

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Infants Visual Capacity

• Based on studies of infant eye movement when a
  striped visual field passes in front of the eyes,
  it is evident that visual capacity increases
  dramatically over the first few months of life.

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Fantz Looking Chamber (1960s)

• Demonstrated that babies less than 2 days old can
  distinguish among visual forms
• Tend, however, to focus on areas of high
  contrast, such as lines and angles

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Development of Visual Scanning
Due to brain maturation
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Perception of Faces

• Infants show a preference for patterned stimuli
  over plain stimuli
• Babies as young as 9 minutes old will look longer
  at a schematic moving face than a scrambled one

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Visual Preferences of Infants
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Expressions of Various Tastes

1. Neutral stimulus (water)
2. Sweet stimulus
3. Sour stimulus
4. Bitter stimulus

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Early Sensory Capacities
Sense Capacity
Hearing Ability to distinguish phonemes Preference for native language
Vision Slightly blurred at birth Color vision by 2 months Distinguish patterned stimuli from plain Preference for facelike stimuli
Smell Ability to differentiate odors well at birth
Taste Ability to differentiate tastes well at birth
Touch Response to touch at birth
Temperature Sensitivity to temperature changes at birth
Position Sensitivity to changes in position at birth
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Response Processes

• Reflexes
• Automatic (involuntary) responses to specific
  types of stimulation
• Emotions
• Two basic emotions, contentment () distress
  (-), split into primary emotions (e.g., joy,
  anger, fear) at 3-6 months
• Temperament
• Individual modes of responding to the environment
  that appear to be consistent across situations
  and stable over time

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Reflexes Present at Birth
Reflex Description
Babinski When the bottom of the babys foot is stroked, the toes fan out and then curl
Crawling When the baby is placed on his stomach and pressure is applied to the soles of his feet, his arms and legs move rhythmically
Moro If the baby is allowed to drop unexpectedly while being held or if there is a loud noise, she will throw her arms outward while arching her back and then bring her arms together as if grasping something
Rooting The baby turns his head and opens his mouth when he is touched on the cheek
Sucking The baby sucks when something is put in her mouth
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Grasping Reflex

• When a finger or some other object is pressed
  against the babys palm, the babys fingers close
  around it
• Disappears in 3-4 months replaced by voluntary
  grasping

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Stepping Reflex

• When the baby is held upright over a flat
  surface, he makes rhythmic leg movements
• Disappears in first 2 months, but can be
  reinstated in special contexts (e.g., when
  partially submerged in water)

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Infant Expression of Emotions
Joy
Anger
Sadness
Disgust
Distress
Interest
Fear
Surprise
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Infant Expression of Emotions
Joy
Anger
Sadness
Disgust
Joy
Anger
Sadness
Disgust
Distress
Interest
Fear
Surprise
Distress
Interest
Fear
Surprise
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Temperaments

• Three broad categories
• Easy babies Playful, regular in their
  biological functions, adapt readily to new
  circumstances
• Difficult babies Irritable, irregular in their
  biological functions, often respond intensely and
  negatively to new situations or try to withdraw
  from them
• Slow-to-warm-up babies Low in activity level,
  responses are typically mild, tend to withdraw
  from new situations, require more time than easy
  babies to adapt to change
• Moderate temperamental stability over first 8
  years of childhood
• Impact of both genetic and environmental
  components

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Coordination with the Social World

• Sleeping
• Feeding
• Crying

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Sleep Patterns in Infants
NREM Sleep
REM Sleep
During first 2-3 months of life, infants begin
their sleep with active (REM) sleep and then fall
into quiet (NREM) sleep. Subsequently, the
sequence reverses and shifts toward the adult
pattern.
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Pattern of Sleep/Wake Cycles
Newborns sleep 16½ hours /day, but the longest
period of sleep is only 3-4 hours.
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Feeding

• When fed on demand, majority of newborns
  preferred a 3-hour schedule
• Interval gradually increased to 4-hour schedule
  by 2 ½ months
• By 7 or 8 months, 4x/day

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Nursing Behavior
Early feeding attempts are rather uncoordinated
Infants nostrils are blocked while he/she is
attempting to feed
This elicits a head-withdrawal reflex that
interferes with feeding
Later attempts become much more coordinated
resulting in nursing an evidence of learning.
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Crying

• Increases from birth to about 6 weeks and then
  starts to decrease
• At a few months of age, infants begin to cry
  voluntarily (crying on purpose) as the
  cerebral cortex becomes involved
• Crying helped by nursing, holding baby to
  shoulder, rocking, patting, cuddling, swaddling
  (reduces over-stimulation from uncontrolled limb
  movements)

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Mechanisms of Developmental Change

• Biological-Maturation Perspective
• Environmental-Learning Perspective
• Constructivist Perspective
• Cultural-Context Perspective

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Mechanisms of Developmental Change

• Biological-MaturationPerspective

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Reflex Coordination

• Early, simple reflexes arise from the brain stem
• More complex, coordinated reflexes result from
  the maturation of the cerebral cortex

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Early Attention to Human Speech

• In 1-month-old baby born without a cerebral
  cortex
• On first exposure to sound of human speech, there
  is a marked decrease in heart rate, indicating
  attention
• After 5 additional presentations of the sound,
  the infant has habituated

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Mechanisms of Developmental Change

• Environmental-LearningPerspective

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Classical Conditioning

1. Sight of a light (CS) elicits no particular
   response
2. Loud sound of gong (UCS) causes baby to blink
   (UCR)
3. Sight of light (CS) is paired with sound of gong
   (UCS), which evokes an eyeblink (UCR)
4. Sight of light (CD) is sufficient to cause the
   baby to blink (CR), evidence that learning has
   occurred

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Operant Conditioning

• An organism will tend to repeat behaviors that
  lead to rewards and will tend to give up
  behaviors that fail to produce rewards or lead to
  punishment
• Requirement Behavior must occur before it can be
  reinforced

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Operant Conditioning

• After only 25 occasions on which the head turning
  was reinforced with the pacifier, most of the
  babies had tripled the rate at which they turned
  their heads.
• Conversely, those infants who were rewarded with
  a pacifier for holding their heads still, learned
  to move their heads less during the course of the
  experiment.

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Mechanisms of Developmental Change

• ConstructivistPerspective(Piaget)

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Piagets Theory of Developmental Change via
Schemas
Assimilation(Incorporated into anexisting
schema)
Accommodation(Modification of aprior schema)
Equilibration
Leads to developmental stages
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Piagets Stages of Cognitive Development
Age (Yrs) Stage Description
Birth 2 Sensori-motor Achievements consist largely of coordinating sensory perceptions and simple motor behaviors. Come to recognize the existence of a world outside themselves and begin to interact with it in deliberate ways.
2 6 Preopera-tional Can use symbols, including mental images, words, and gestures. Often fail to distinguish their point of view from that of others, become easily captured by surface appearances, and are often confused about causal relationships.
6 12 Concrete Operational Become capable of mental operations that allow them to combine, separate, order, and transform objects and actions. There are still carried out, however, in the presence of the objects and events being thought about.
12 19 Formal Operational Acquire the ability to think systematically about all logical relations within a problem. Display keen interest in abstract ideas and in the process of thinking itself.
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Sensorimotor Substages
Sub Age (M) Description
1 0 1 ½ Reflex schemas exercised Involuntary rooting, sucking, grasping, looking
2 1 ½ 4 Primary circular reactions Repetition of actions that are pleasurable in themselves
3 4 8 Secondary circular reactions Dawning awareness of the effects of ones own actions on the environment, and that extended actions can produce interesting change in the environment
4 8 12 Coordination of secondary circular reactions Combining schemas to achieve a desired effect (earliest form of problem solving)
5 12 18 Tertiary circular reactions Deliberate variation of problem-solving means, with experimentation to see what the consequences will be
6 18 24 Beginning of symbolic representation Images and words come to stand for familiar objects, accompanied by the invention of new means of problem solving through symbolic combinations
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Mechanisms of Developmental Change

• Cultural-ContextPerspective

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Reciprocal Relationships

• Presence of milk stimulates infant sucking, which
  in turn triggers the release of hormones that
  increase milk production and release

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Developmental Change Incorporates Cultural
Variations

• Additional sources of developmental change
• Active contribution of other people in the
  childs community
• Cultural designs for living accumulated over
  the history of the larger social group

Case in PointBottle-feeding vs. Breast-feeding
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First PostnatalBio-Social-Behavioral Shift

• Occurs at 2½ MonthsSocial Smiling!

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BSB Shifts Subsequent Periods
Shift Point Developmental Period
Conception Prenatal period
Birth Early infancy
2 ½ months Middle infancy
7-9 months Late infancy
24-30 months Early childhood
5-7 years Middle childhood
11-12 years Adolescence
19-21 years Adulthood
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Characteristics of the Shift
Biological Myelination of cortical and subcortical neural pathways Increased cortical control of subcortical activity Increased diversity of brain cells Increase in amount of wakefulness Decrease in proportion of active (REM) sleep Quiet (NREM) sleep begins to come first
Social New quality of coordination and emotional contact between infants and caretakers Beginning of crying on purpose
Behavioral Better retention of learning Increased visual acuity and better visual scanning Onset of social smiling Decreased fussiness and crying Visually initiated reaching ? visually guided reaching