Download body proportions in infancy and early childhood

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Physical Development in
Infancy and Toddlerhood
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Dr. Kuther's Chalk Talks: Part II
Kuther, Lifespan Development. © 2017, SAGE Publications.
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VIDEO CASE
BODY PROPORTIONS IN INFANCY AND EARLY CHILDHOOD
Watch 13-month-old London, 3-year-old Ella, and 4-year-old Abigail as
they demonstrate changing body proportions from infancy to early
childhood.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Body Growth
– Cephalocaudal development
• Growth proceeds from the head downward.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Body Growth
– Proximodistal development
• Growth and development proceed from the
center of the body outward.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Growth Norms
• Expectations for typical gains and variations in
height and weight for children based on their
chronological age and ethnic background
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Breast-Feeding
– One of the best ways of meeting infants’ complex
nutritional needs
– Recommended by the U.S. Department of Health and
Human Services
– In the U.S., over three quarters of mother breast-fed
in 2010.
– 40% continue to breast-feed after 6 months; 27%
continue to breast-feed at 12 months.
– Breast-feeding practices vary by ethnicity, education,
socioeconomic status, and maternal age.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Factors that Influence Breast-Feeding
– Paid maternity leave for part or all of an infant’s
first year of life
• Denmark, Norway, Sweden, and Australia have breastfeeding rates of 94% and more.
– Income level and education
• In the U.S. and U.K., the lowest rates of breast-feeding
are among low-income mothers and mothers with low
levels of education.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Benefits of Breast-Feeding: Mothers
• Lower rates of:
– Diabetes
– Cardiovascular disease
– Depression
– Ovarian cancer (after menopause)
– Breast cancer (after menopause)
– Bone fractures (after menopause)
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Benefits of Breast-Feeding: Infants
• Easier to digest vs. formula
• Immunizing agents that protect the infant against
infections
• Cognitive advantage
• Reduced risk of:
–
–
–
–
–
Sudden infant death syndrome (SIDS)
Allergies
Gastrointestinal symptoms
Obesity (breast-feeding over 6 months)
Childhood cancer (breast-feeding over 6 months)
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sleep
• The typical newborn sleeps about 18 hours
each day, waking every 2 hours to eat.
– Nighttime feedings continue through five months
of age.
• By 8 weeks of age, infants begin to show signs
of day-night sleep rhythms.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Solid Food
• First solid foods are introduced between 4 and
6 months of age.
– Starting with iron-fortified baby cereal mixed with
breast milk or formula.
– As they get older, add pureed foods (vegetables
and fruits), add pureed meats later.
• Many foods must be introduced over a dozen
times before an infant will accept them.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Malnutrition
• Over one quarter of the world’s children under
age 5 are moderately or severely underweight.
• In 2012, 15% of American households
experienced food insecurity (lack of consistent
access to food).
• The most common nutrients missing from infants
and toddlers’ diets are iron, zinc, and calcium.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Malnutrition: Marasmus
– A wasting disease in which the body’s fat
and muscle are depleted
• Growth stops, the body wastes away, the skin
becomes wrinkly and aged looking, the
abdomen shrinks, and the body takes on a
hollow appearance .
– Results from a diet that is chronically
insufficient in protein and calories
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Malnutrition: Kwashiorkor
• Found in children who experience a sudden
deprivation of food and calories
• Characterized by:
– Lethargy
– Wrinkled skin
– Bloating and swelling of the stomach, face, legs
and arms
– Hair becomes thin, brittle, and colorless
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Consequences of Malnutrition
– Impaired learning, concentration, and
language skills throughout childhood and
adolescence
– Stunted growth
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Failure to Thrive
• A condition in which an infant’s weight is less
than 80% of the norm for their age without
any medical reason, such as illness
• Common causes:
– Inadequate nutrition
– Eating too few calories
– Psychosocial and contextual factors
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Processes of Neural Development
• Neurons
– Brain cells that are specialized to communicate with
one another to make it possible for people to sense
the world, think, move their body, and carry out their
lives
• Neurogenesis
– The creation of new neurons that begins in the
embryo’s neural tube
– We are born with more than 100 billion neurons
(more than we need and more than we will ever have
at any other time in our lives).
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Neural Development: Glial Cells
• A second type of brain cell that outnumbers
neurons 10 to 1
• Nourishes neurons and move throughout the
brain to provide a physical structure to the
brain; instructs neurons to form connections
with other neurons
• Neurons migrate along a network of glial cells.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 4.4: Glial Cell-Neuron Relationship
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Neural Development: Synaptogenesis
• A process in which neurons form synapses and
thereby increase connections with other
• Peaks in different brain regions at different ages
• Transient exuberance – the explosion in
connections in the early years of life
– The brain makes more connections than it needs in
preparation to receive any and all conceivable kinds of
stimulation.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Neural Development: Synaptic Pruning
• The loss of unused neural connections
– The connections that are used become stronger
and more efficient, while those unused eventually
shrink, atrophy, and disappear.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Neural Development: Myelination
• A process which begins during the first two
years of life
• Glial cells produce and coat the axons of
neurons with a fatty substance called myelin.
– Myelination contributes to advances in neural
communication because axons coated with myelin
transmit neural impulses more quickly than
unmyelinated axons.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Experience and Brain Development
• Infants who are understimulated show cognitive and
perceptual deficits.
• Experience influences the physical structure of our
brains throughout life.
• Experience-expectant brain development
– The brain depends on experiencing certain basic events
and stimuli at key points in time to develop normally.
• Experience-dependent brain development
– Growth that occurs in response to learning experiences
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Habituation
• Occurs when
repeated exposure
to a stimulus
results in the
gradual decline in
the intensity,
frequency, or
duration of a
response
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Classical Conditioning
– Learning through association
• An association is made between a neural
stimulus and an unconditioned stimulus that
triggers an innate reaction.
• Eventually, the neutral stimulus (now
conditioned stimulus) produces the same
response as the unconditioned stimulus.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Operant Conditioning
– Infants learn to engage in behaviors based
on their consequences, whether they are
followed by reinforcement or punishment.
• Behaviors increase when they are followed by
reinforcement.
• Behaviors decrease when they are followed by
punishment.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Imitation
• Imitation is an important way in which
children and adults learn.
• Classic study:
– Two-day-old infants mimicked adult facial
expressions including sticking out the tongue,
opening and closing the mouth, and sticking out
the lower lip.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Figure 4.6: Newborn Imitating Facial Expressions
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Imitation: Innate Programming
• The ability to copy others’ actions is inborn
and may have fostered the evolutionary
development of social communication.
• Newborns do not understand imitation, rather
their facial expressions naturally mimic others;
imitation becomes voluntary over time.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Deferred Imitation
• The ability to imitate an absent model
• Six- and 9-month-old infants show deferred
imitation after 24 hours.
• Twelve-month-old infants display deferred
imitation four weeks after observing a
model manipulate toys like cups, beads, and
blocks.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sensation and Perception
• Sensation
– Occurs when our senses detect a stimulus
• Perception
– The sense our brain makes of a stimulus and our
awareness of it
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sensation and Perception: Hearing
• The capacity to hear develops in the womb
and is the most well-developed sense at birth.
– Newborns are able to hear about as well as adults.
• Shortly after birth, neonates can discriminate
among sounds.
• By 3 days of age, infants can turn their head
and eyes in the general direction of a sound.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sensation and Perception: Vision
• Vision is the least developed sense at birth,
but it improves rapidly.
– Visual acuity – the sharpness of vision or the
ability to see
• Studied through preferential looking
– Tasks designed to determine whether infants prefer to look at
one stimulus or another
• Newborn visual acuity is approximately 20/400.
• Infants reach adult levels of visual acuity between 6
months and 1 year of age.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Depth Perception
• The ability to perceive
distance
• Classic study – The visual
cliff (crawling influences
how infants perceive
depth)
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sensation and Perception: Touch
• Less is known about the sense of touch in infants.
• Touch can reduce stress responses in preterm and
full-term neonates.
• Touch is associated with weight gain in newborns.
• Skin-to-skin contact with a caregiver has an
analgesic effect (reducing infants’ pain response
to the heel stick).
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sensation and Perception: Smell and Taste
• Well developed at birth
• Newborns can discriminate between smells.
• Infants show innate preferences for some
tastes:
– Preference for human milk
– Preference for sugar to other substances
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Sensation and Perception: Intermodal Perception
• The process of combining information from
more than one sensory system
• Research on intermodal perception supports
the finding that infants expect vision,
auditory, and tactile information to occur
together.
• Intermodal relations among sense are not
bidirectional at birth.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Motor Development: Reflexes
• The earliest ways in which infants adapt are
through the use of their reflexes (involuntary
and automatic responses to stimuli such as
touch, light, and sound).
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Table 4.1: Newborn Reflexes
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Motor Milestones
• Motor skills evolve
in a predictable
sequence.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Gross Motor Development
• The ability to control the large movements of
the body
– The first milestone in gross motor development is
the ability to roll over voluntarily (3 months of
age).
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Fine Motor Development
• The ability to control small movements of the
fingers such as reaching and grasping
• Voluntary reaching plays an important role in
cognitive development because it provides
new opportunities for interacting with the
world (appears at about 3 months of age).
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Determinants of Motor Development
• Maturation
– For instance, preterm infants reach milestones later
than do full-term infants.
– Cross-cultural support – infants display roughly the
same sequence of motor milestones.
• Practice
– For instance, when infants from 1 to 7 weeks of age
practice stepping reflexes each day, they retain the
movement and walk earlier than infants who receive
no practice.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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VIDEO CASE
Motor Development in Infancy
Observe 5-month-old Marlee, 10-month-old Damian, and 13-month-old
London as they demonstrate milestones of motor development, moving
from pushing up from their chest, to sitting, rolling over, crawling, and
standing.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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Motor Development as a Dynamic System
• Separate abilities are blended together to
provide more complex and effective ways of
exploring and controlling the environment.
• Motor development reflects goal-oriented
behavior.
Kuther, Lifespan Development. © 2017, SAGE Publications.
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