Santrock Life-span development 16th edition slides.

1. LIFE-SPAN DEVELOPMENT
Sixteenth Edition
Chapter 4
Physical
Development
in Infancy
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prior written consent of McGraw-Hill Education.

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Chapter Outline
• Physical growth and development in infancy
• Motor development
• Sensory and perceptual development

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Physical Growth and Development
in Infancy
• Patterns of growth
• Height and weight
• The brain
• Sleep
• Nutrition

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Patterns of Growth
• Cephalocaudal pattern
– Developmental sequence in which the earliest
growth always occurs at the top, with physical
growth and differentiation of features
gradually working their way down from top to
bottom
• Proximodistal pattern: Sequence in which
growth starts at the center of the body and
moves toward the extremities

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Changes in Proportions of the Human
Body During Growth

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Height and Weight
• The average American newborn is 20 inches
long and weighs 7 pounds
• Most of the newborns are 18 to 22 inches
long and weigh between 5 and 10 pounds
• Grow about 1 inch per month during the first
year
• By 2 years of age
– Infants weigh approximately 26 to 32 pounds
– Average 32 to 35 inches in height

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The Brain (1 of 6)
• Contains approximately 100
billion neurons at birth
• Shaken baby syndrome
– Brain swelling and
hemorrhaging
• Electroencephalogram -
Measure of the brain’s
electrical activity
– Help learn about the brain’s
development in infancy

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The Brain (2 of 6)
• Brain’s development
– Mapping the brain
 Forebrain - Portion farthest from the spinal
cord, includes the cerebral cortex and
structures beneath it
 Brain has two hemispheres, each hemisphere
constitutes of four lobes
o Lateralization: Specialization of function in one
hemisphere of the cerebral cortex or the other

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The Brain (3 of 6)
• Neurons
– a nerve cell that handles
information processing
• Myelin sheath
– a layer fat cells that helps
electrical signals travel
faster down the axon
• Neurotransmitters
– Tiny gaps between
neuron’s fibers

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The Brain (4 of 6)
• Changes in neurons
– Myelination
– Connectivity among neurons increases
• Changes in regions of the brain
– Blooming and pruning vary by brain region
– Peak of synaptic overproduction in the visual
cortex followed by a gradual retraction
 Heredity and environment influence the timing
and course
– Pace of myelination varies

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The Brain (5 of 6)
• Early experience and the brain
– Children in deprived environment may have
depressed brain activity
 Ex: Romanian Orphanage
– Brain demonstrates both flexibility and
resilience
 Ex: Michael Rehbein

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The Brain (6 of 6)
• Neuroconstructivist view
– Biological processes and environmental
conditions influence the brain’s development
– Brain has plasticity and is context-dependent
– Development of the brain and the child’s
cognitive development are closely linked

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The Brain’s Four Lobes

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Synaptic Density in the Human
Brain from Infancy to Adulthood

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Early Deprivation and Brain Activity

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Sleep (1 of 4)
• Why Do We Sleep?
– Evolutionary perspective
 Sleep necessary for survival
– Replenishes and rebuilds the brain and body
 Restorative function
 Clearing out waste in neural tissue
– Critical for brain plasticity
 Increases synaptic connections between
neurons

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Sleep (2 of 4)
• Typical newborn sleeps approximately 18
hours a day
• Infant sleep-related problem - Nighttime
waking
• Cultural variations influence infant sleeping
patterns
• REM sleep - Eyes flutter beneath closed lids
– Approximately half of an infant’s sleep is REM
sleep

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Sleep (3 of 4)
• Shared sleeping
• Sudden infant death syndrome (SIDS):
Occurs when an infant stops breathing,
usually at night
– Suddenly dies without an apparent cause

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Sleep (4 of 4)
• Sleep and Cognitive Development
– Sleep may be linked to cognitive development
 Likely occurs because of sleep’s role in brain
maturation and memory consolidation
– Lower quality of sleep linked with behavioral
problems

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SIDS: Findings (1 of 2)
• SIDS is likely in infants:
– With abnormal brain stem functioning
involving the neurotransmitter serotonin
– With sleep apnea and low birth weight
– Who do not use a pacifier when they go to
sleep
– Whose siblings have died of SIDS
– Lower socioeconomic groups
– Who are passively exposed to cigarette smoke
– Share the same bed with parents or sleep on
soft bedding

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SIDS: Findings (2 of 2)
• SIDS is less common in infants who:
– Are breast fed
– Sleep in a bedroom with a fan
• African American and Eskimo infants are four
to six times as likely as all others to die of
SIDS

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Developmental Changes in REM
and Non-REM Sleep

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Nutrition (1 of 5)
• Nutritional needs and eating behavior
– Infants should consume approximately 50
calories per day for each pound they weigh
– As motor skills improve, infants change:
 From using suck-and-swallow movements
 To chew-and-swallow movements with
semisolid and then complex foods
– Need to have a diet that includes:
 Fruits and vegetables

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Nutrition (2 of 5)
• Breast versus bottle feeding
– Breast feeding is better
• Benefits of breast feeding: outcomes for the
child
– Lower gastrointestinal infections
– Lower respiratory tract infections
– No evidence reduction in the risk of allergies
– Protects against wheezing in babies, but
whether it prevents asthma in older children is
unclear

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Nutrition (3 of 5)
– Less likelihood to:
 Develop middle ear infection
 Become overweight or obese in childhood,
adolescence, and adulthood
 Develop Type 1 diabetes in childhood
 Experience SIDS
• Benefits of breast feeding: outcomes for the
mother
– Lower incidence of breast cancer and ovarian
cancer
– Small reduction in type 2 diabetes

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Nutrition (4 of 5)
• Mother should not breast feed:
– When infected with HIV or some other
infectious disease
– If she has active tuberculosis
– If she is taking any drug

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Nutrition (5 of 5)
• Malnutrition in infancy
– Marasmus: Wasting away of body tissues in
the infant’s first year
 Caused by severe protein-calorie deficiency
– Kwashiorkor: Caused by severe protein
deficiency
 Child’s abdomen and feet become swollen with
water
 Appears between 1 and 3 years of age

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Motor Development
• The dynamic systems view
• Reflexes
• Gross motor skills
• Fine motor skills

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Dynamic Systems View
• Dynamic systems theory: Infants assemble
motor skills for perceiving and acting
• Motor skills are developed by:
– Development of the nervous system
– Body’s physical properties and its possibilities
for movement
– Child’s motivation to reach a goal
– Environmental support for the skill

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Reflexes (1 of 3)
• Built-in reactions to stimuli that govern the
newborn’s movements
• Are automatic and beyond the newborn’s
control
• Rooting reflex: Occurs when the infant’s
cheek is stroked or the side of the mouth is
touched
– Turns his or her head in an effort to find
something to suck

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Reflexes (2 of 3)
• Sucking reflex: Occurs when newborns
automatically suck an object placed in their
mouth
– Enables newborns to get nourishment before
they have associated a nipple with food
– Serves as a self-soothing mechanism

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Reflexes (3 of 3)
• Moro reflex: A neonatal startle response that
occurs in reaction to a sudden, intense noise
or movement
– It is believed to be a way of grabbing for
support while falling
• Grasping reflex: Occurs when something
touches the infant’s palms
– Responds by grasping tightly

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Gross Motor Skills (1 of 2)
• Involve large-muscle activities, such as
walking
• Development of posture
– Posture - Dynamic process linked with sensory
information in the skin, joints, and muscles,
which tell us where we are in space
• Learning to walk
• The first year
– Motor development milestones and variations

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Gross Motor Skills (2 of 2)
• Development in the second year
– Toddlers become more skilled and mobile
– By 13-18 months
 Toddlers can pull a toy or climb stairs
– By 18-24 months
 Toddlers can walk quickly
 Balance on their feet
 Walk backward and stand and kick a ball

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Milestones in Gross Motor
Development

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Fine Motor Skills
• Involve more finely tuned movements, such
as finger dexterity
• Types of grasps
– Palmer grasp
– Pincer grip

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Sensory and Perceptual Development
• What are sensation and perception?
• The ecological view
• Visual perception
• Other senses
• Intermodal perception
• Nature, nurture, and perceptual development
• Perceptual-motor coupling

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What are Sensation and Perception?
• Sensation: Occurs when information interacts
with sensory receptors
– Eyes, ears, tongue, nostrils, and skin
• Perception: Interpretation of what is sensed

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The Ecological View
• Perception functions to bring organisms in
contact with the environment and to increase
adaptation
– Affordances: Opportunities for interaction
offered by objects that fit within our
capabilities to perform functional activities