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Chapter 2: Infancy
Module 2.1
Physical Development
in Infancy
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
GROWTH AND STABILITY
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Physical Growth
• Rapid growth during first two years
87
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
An Interesting Head Count
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Nervous System and Brain
• Nervous system
comprises the brain
and the nerves that
extend throughout the
body
• Neurons are the
basic cells of the
nervous system
87
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Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Quick Check
•
•
•
•
•
Neurons
Dendrites
Axons
Neurotransmitters
Synapses
87
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
Brain Physiology
• Structure and function
– Forebrain
– Cerebral cortex has four lobes
• Two hemispheres usually work together
and each lobe has a primary function
• Frontal, occipital, temporal, parietal lobes
– Amygdala
– Hippocampus
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
The
Brain’s
Four
Lobes
Discovering the Lifespan - Robert S. Feldman
Fig. 3.7
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
Functions of Lobes of the Cortex
Frontal lobes
Involved in voluntary movement,
thinking, personality, and
intentionality or purpose
Occipital lobes Function in vision
Temporal lobes
Parietal lobes
Active role in hearing, language
processing, and memory
Roles in registering spatial location,
attention, and motor control
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Development of the Brain
• By age 6, almost adult size.
• Brain growth spurts: coincide with changes
in cognitive behavior
• Cerebellum, largest part of brain, divides into
halves
• Lateralization, specialties of each
hemisphere; left: language and logical
thinking; right: visual and spatial functions
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
Brain Physiology
• Neurons — nerve cells handling information
processing at the cellular level
–
–
–
–
Axon, dendrites, synapses
Neurotransmitters: dopamine
Myelin sheath and myelination
Neural circuits
• Lateralization — specialization of functions
in one hemisphere of cerebral cortex
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
The Neuron
Discovering the Lifespan - Robert S. Feldman
Fig. 3.8
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
The Brain In Infancy
• Shaken Baby Syndrome
• Extensive brain development in utero
– Born with about 100 billion neurons
– Enriched early experiences can enhance brain
growth and functioning
– Brain flexibility and resilience demonstrated in
deprived environments
• Experience determines brain connections
– Enriched and deprived environments
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
The Brain In Infancy
• Changing neurons
– Myelination; visual and auditory
– Rapid growth of myelin sheath, dendrite and
synapse connections
– Blooming and pruning of connections in brain
– Peak synaptic overproduction influenced by
heredity and environment
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Brain
The Brain In Infancy
• At birth, greater activity in left
hemisphere specializes as infants
listen to speech
• Motor control begins about 2 months
• Brain areas do not mature uniformly;
skills affected by myelination and
interconnections
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Major Systems of the Brain
• Brain stem
• Limbic system
• Cerebral cortex
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
How great brains grow!
• Birth:
– 100-200 billion
neurons
– Relatively few
neurons-neuron
connections
• During first two years:
– Billions of new
connections
established and
become more complex
88
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Use it or lose it!
Synaptic pruning
• Unused neurons are eliminated
• Allows established neurons to build more
elaborate communication networks with
other neurons
• Development of nervous system proceeds
most effectively through loss of cells
• Myelin
88
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Form and Function: Brain
Growth
• Neurons reposition themselves with
growth, becoming arranged by function
– Cerebral cortex
– Subcortical levels
89
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Don’t shake the baby!
• Shaken Baby Syndrome
– Brain sensitive to form forms of injury
– Shaking can lead to brain rotation within
skull
• Blood vessels tearsevere medical
problems, long-term disabilities, and
sometimes death
89
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Environmental Influences on Brain
Development
• Plasticity
• Sensitive period
89
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Critical Period: specific time when a
given event (or absence) has
specific impact on development.
Not absolutely fixed.
Plasticity: ability to modify
Sensitive Periods: especially
responsive to specific type of
experience
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Without feedback from the
environment (that is, without
experience) how can further
development occur?
A child raised in a deprived
environment with inadequate
stimulation and feedback might
fail to learn. The damage to a
child is significant when love and
attention are absent.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Critical & Sensitive Periods
Critical and sensitive periods are
both times when the organism is
biologically primed to most benefit
from a particular experience.
Sensitive Periods: adverse effects
caused by missing a sensitive
period may be overcome at a later
time, although with great difficulty.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Critical Periods: adverse effects caused
by missing a critical period are
permanent.
The only clearly demonstrated critical
period in human beings involves early
stimulation of certain neural and body
cells. Without such stimulation, these
cells atrophy and die (e.g., visual
neurons must have light during their
early development or they will die.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The first 5 to 6 years of childhood may
be a critical period for the
development of the brain.
Even when a part of the brain is
damaged, if damage occurs before
age 5/6, the brain may compensate
and take over the functions. After
age six, highly unlikely.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Other ways a child may suffer permanent
disability by early childhood:
1. occurrence of irreparable physical
damage upon which later development
will depend
2. a critical period that passes without the
child’s obtaining the necessary
experience or stimulation
3. a situation where the child is kept by
their culture or environment from ever
obtaining the learning necessary for
proper development.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Do Baby Einstein programs
really work?
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
What do babies do all day?
Life Cycles of Infancy
• Wake
• Sleep
• Eat
• Defecate
89
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Rhythms and States
• State
– One of major body rhythms
– Degree of awareness infant displays to both
internal and external stimulation
– Change in state alters amount of stimulation
required to get infant’s attention
90
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Sleep: Perchance to Dream
• Major state
– 16-17 hours daily (average); wide variations
• Different than adult sleep
– 2 hour spurts; periods of wakefulness
– Cyclic pattern
• By 16 weeks sleep about 6 continuous
hours; by 1 year sleep through night
(See table 2-2)
90-91
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
REM Sleep
• Period of active sleep
• Closed eyes begin to
move in a back-and-forth
pattern
• Takes up around one-half
of infant sleep
• May provide means for
brain to stimulate itself
through autostimulation
91
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
SIDS
•
•
•
•
Sudden infant death syndrome
Leading cause of death in children under 1 year of age
Back-to-sleep guidelines (AAP)
Differential risk
–
–
–
–
–
–
–
Boys
African American infants
Low birthweight
Low APGAR scores
Mother’s smoking
Some brain defects
Child abuse
92
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
SIDS is found in children of every race
and socioeconomic group and in
children who have had no apparent
health problems
Back-to-sleep is important!
92
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Review and Apply
93
REVIEW
• The major principles of growth are the
cephalocaudal principle, the proximodistal
principle, the principle of hierarchical integration,
and the principle of the independence of
systems.
• The development of the nervous system first
entails the development of billions of neurons
and interconnections among them. Later, the
numbers of both neurons and connections
decrease as a result of the infant’s experiences.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Review and Apply
REVIEW
• Babies integrate their individual behaviors
by developing rhythms—repetitive, cyclical
patterns of behavior.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
93
Review and Apply
APPLY
• What evolutionary advantage could there
be for infants to be born with more nerve
cells than they actually need or use? How
might our understanding of synaptic
“pruning” affect the way we treat infants?
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
93
MOTOR DEVELOPMENT
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Reflexes: Inborn Physical Skills
• Reflexes: learned, organized involuntary
responses that occur automatically in
presence of certain stimuli
93
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
What did you see?
• Take two minutes to list the reflexes you
saw in the clip.
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Why do reflexes come and go?
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Ethnic and Cultural Differences and
Similarities in Reflexes
• Reflexes
– Genetically determined
– Universal
• Cultural variations in
ways displayed
– Moro reflex
• Serves
– Diagnostic tool
– Social function
– Survival function
94
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Motor Development in Infancy
Milestones of Normal Motor Development
96
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Motor Development in Infancy
Fine Motor Skills
96
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Developmental Norms
Comparing Individual to Group Norms:
– Represent the average performance of a
large sample of children of a given age.
– Permit comparisons between a particular
child’s performance on a particular behavior
and the average performance of the children
in the norm sample.
– Must be interpreted with caution.
• Brazelton Neonatal Behavior Assessment Scale (NBAS)
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
96
Nutrition in Infancy
Fueling Motor Development
• Without proper nutrition, infants cannot
reach physical potential and may suffer
cognitive and social consequences
• Infants differ in growth rates, body
composition, metabolism, and activity
levels
98
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
So what is a healthy caloric
allotment for infants?
• About 50 calories per day for each pound
of weight
• Most infants regulate their caloric intake
quite effectively on their own
• If are allowed consume as much they
seem to want, and not pressured to eat
more, they will be healthy
98
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Malnutrition
• Children living in many developing
countries
• Slower growth rate
• Chronically malnourished during infancy =
later lower IQ score
98
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Are problems of
malnourishment restricted to
developing countries?
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
When Malnutrition Is Severe
• Maramus
• Kwashiorkor
98
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Nonorganic Failure to Thrive
• Sufficient nutrition
• Symptoms
• Reversal
99
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
“A fat baby
is a
healthy baby”?
99
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Is Breast Best?
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Introducing Solid Foods: When
and What?
• Solids can be started at 6 months but are
not needed until 9 to 12 months (AAFP)
– Introduced gradually, one at a time
– Cerealstrained fruits
100
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Review and Apply
REVIEW
• Reflexes are universal, genetically acquired
physical behaviors.
• During infancy children reach a series of
milestones in their physical development on a
fairly consistent schedule, with some individual
and cultural variations.
101
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Review and Apply
REVIEW
• Nutrition strongly affects physical development.
• The advantages of breast-feeding are
numerous.
101
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Review and Apply
APPLY
• What advice might you give a friend who is
concerned that her infant is still not walking at 14
months, when every other baby she knows started
walking by the first birthday?
101
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Learning the World
• Sensation
• Perception
101
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Visual Perception: Seeing the
World
• Newborn’s distance vision ranges from
20/200 to 20/600
• By 6 months, average infant’s vision is
already 20/20
• Other visual abilities grow rapidly
– Binocular vision
– Depth perception
102
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Infant Visual Preference
• Preferences that are
present from birth
– Genetically
preprogrammed to
prefer particular kinds
of stimuli
– Prefer to look at
patterned over simpler
stimuli
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
102
Auditory Perception: The World
of Sound
• Infants
– Hear before birth and have good auditory
perception after they are born
– Are more sensitive to certain frequencies
– Reach adult accuracy in sound localization by
age 1
– Can discriminate groups of different sounds
– React to changes in musical key and rhythm
– Can discriminate many language related
sounds
103
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Smell and Taste in a Small
World
• Smell
– Well developed at birth
– Helps in recognition of mother early in life
• Taste
– Have innate sweet tooth
– Show facial disgust at bitter taste
– Develop preferences based on what mother
ate during pregnancy
103
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
The Power of Touch
• Touch is one of most highly developed
sensory systems in a newborn
• Even youngest infants respond to gentle
touches
• Several of the basic reflexes present at
birth require touch sensitivity to operate
104
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Becoming an Informed
Consumer of Development
Exercising Your Infant’s Body and Senses
• Attempts to accelerate physical and sensoryperceptual development yield little success
»Yet
• Infants need sufficient physical and sensory
stimulation
105
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
How can this be accomplished?
•
•
•
•
Carry a baby in different ways
Let infants explore their environment
Engage in “rough-and-tumble” play
Let babies touch their food and even play
with it
• Provide toys that stimulate the senses,
particularly toys that can stimulate more
than one sense at a time
105
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
Review and Apply
REVIEW
• Infants’ sensory abilities are surprisingly well developed
at or shortly after birth. Their perceptions help them
explore and begin to make sense of the world.
• Very early, infants can see depth and motion, distinguish
colors and patterns, localize and discriminate sounds,
and recognize the sound and smell of their mothers.
• Infants are sensitive to pain and touch, and most medical
authorities now subscribe to procedures, including
anesthesia, that minimize infants’ pain.
106
Discovering the Lifespan - Robert S. Feldman
Copyright © 2009 Pearson Education, Inc., Upper Saddle River, NJ 07458. All rights reserved.
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