1. Life-Span Development
Twelfth Edition
Chapter 4:
Physical Development in Infancy
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2.  Patterns of Growth:
 $$ Cephalocaudal Pattern: sequence in which
the earliest growth always occurs from the top
downward
▪ Also applies to gains in motor development
 Proximodistal Pattern: sequence in which growth
starts in the center of the body and moves toward
the extremities
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3.  Height and Weight:
 Average North American newborn is 20 inches
long and 7 ½ pounds
▪ 95% of full-term newborns are 18-22 inches long and
weigh between 5 ½ and 10 lbs.
▪ Newborns lose 5-7% of their body weight in the first few
days of life
▪ They typically gain 5-6 ounces per week during the first month
 Weight usually triples by their 1st birthday
▪ Newborns gain approximately 1 inch per month during
the first year
 Growth slows considerably during the 2nd year
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5.  The Brain:
 Brain continues developing past infancy
 Shaken Baby Syndrome: brain swelling and
hemorrhaging from child abuse trauma
 Brain imaging technologies cannot typically be used
with babies
▪ EEGs show regular spurts in the brain’s electrical activity
▪ Spurts may coincide with important changes in cognitive
development
 At birth, the brain is 25% of its adult weight; at 2
years of age, it is 75% of its adult weight
▪ The brain does not mature uniformly
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6.  Forebrain: portion of the brain farthest from the
spinal cord; includes cerebral cortex
 Lateralization: specialization of function in one
hemisphere of the cerebral cortex or the other
 Some functions are lateralized, some are not
▪ Complex functions involve communication between both
hemispheres
$$ Electroencephalogram (EEG) is
commonly used to study the brain in
infancy.
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7.  Neurons: brain nerve cells that communicate
through electrical and chemical signals
 Axons carry signals away from the cell body
 Dendrites carry signals toward the cell body
 Myelin sheath is a layer of fat cells that insulate axons
▪ Helps electrical signals travel faster
 Terminal buttons release chemicals
(neurotransmitters) into synapses
▪ Synapses: tiny gaps between neurons
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8.  Depressed brain activity has been found in children who grow up in a
deprived environment
 Enriched environments promote faster brain development than deprived ones
 After birth: sights, sounds, smells, touches, language, and eye contact
help shape the brain’s neural connections
 Repeated experience wires (and rewires) the brain
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9.  Typical newborns sleep 16-17 hours per day
 Infants vary in their preferred times for sleeping
 Most have moved closer to adult-like sleep patterns
by 4 months of age
 Factors involved in night waking:
 Daytime crying and fussing
 Distress when separated from mother
 Breast feeding
 Co-sleeping
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10.  The practice of shared sleeping, in which a newborn shares a bed with mother,
varies among cultures
 Potential benefits:
 Promotes breast feeding and a quicker response to crying
 Allows mother to detect potentially dangerous breathing pauses in baby
 American Academy of Pediatrics discourages shared sleeping
 Increases risk of injury (rolling over baby) and SIDS
 $$ SIDS (Sudden Infant Death Syndrome): infants stop breathing
and die without apparent cause
 Highest cause of infant death in U.S. annually
 Highest risk is 2-4 months of age
 Risk decreases when infant sleeps on its back and when a
pacifier is used
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11.  Experts recommend that infants consume 50
calories per day for each pound they weigh
 U.S. parents typically do not feed infants
enough fruits and vegetables
 By 15 months, French fries are the most common
vegetable eaten
 Increasing rates of overweight and obese
infants
 Other factors:
▪ Mother’s weight gain during pregnancy and pre-pregnancy
weight
▪ Breast feeding vs. bottle feeding
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12.  American Academy of Pediatrics strongly endorses breast feeding
throughout the first year
 Benefits for baby can include:
 Fewer gastrointestinal and lower respiratory tract infections
 Potentially decreased risk of asthma
 Less likely to become overweight or obese
 Less incidence of diabetes
 Less likely to experience SIDS
 Benefits for mother can include:
 Lower incidence of breast and ovarian cancer
 Lower incidence of Type 2 diabetes
 Breast feeding does not:
 Help mother return to pre-pregnancy weight
 Guard against osteoporosis
 Decrease likelihood of experiencing post-partum depression
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13.  Women less likely to breast feed:
 Mothers who work full-time outside of the home
 Mothers under age 25
 Mothers without a high school education
 African-American mothers
 Mothers in low-income circumstances
 Malnutrition in Infancy:
 Early weaning and inadequate sources of nutrients can cause malnutrition
 Marasmus: a severe protein-calorie deficiency
▪Results in a wasting away of body tissues
 Kwashiorkor: a severe protein deficiency that causes the abdomen and feet to
swell with water
▪Causes the vital organs to collect nutrients, depriving other parts of the body
 Severe and lengthy malnutrition is detrimental to physical, cognitive, and social
development
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14.  Dynamic Systems View:
 Infants assemble motor skills for perceiving and
acting
▪ Motor skills represent solutions to goals
▪ $$ Arnold Gesell believed that motor skills come about
through maturation
 Development is an active process in which nature
and nurture work together
▪ Development of nervous system
▪ Body’s physical properties and possibilities for movement
▪ Goal the child is motivated to reach
▪ Environmental support for the skill
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15.  Reflexes: built-in reactions to stimuli; generally
carry survival mechanisms
 Rooting Reflex: when the infant’s cheek is stroked, the infant will
turn its head to the side that was touched
 Moro Reflex: automatic arching of back and wrapping of arms to
center of body
when startled
 Grasping Reflex: infant’s hands close around anything that touches
the palms
 Some reflexes continue throughout life; others
disappear several months after birth
 Gross Motor Skills: skills that involve large-muscle
activities
 Walking, grabbing for objects
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16.  Development in the 2nd Year:
 Toddlers become more skilled and mobile
 Motor activity is vital to the child’s development of
competence and independence
 By 18-24 months, toddlers can:
▪ Walk quickly or run stiffly
▪ Balance on their feet in a squat position
▪ Walk backward
▪ Stand and kick a ball without falling
▪ Jump in place
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17.  Fine Motor Skills: involve finely tuned movements
 Reaching and grasping is a significant milestone for infants
 Palmer grasp: grasping with the whole hand
 Pincer grip: grasping with the thumb and forefinger
 Perceptual-motor coupling is necessary for infants to
coordinate grasping
 Experienced infants look at objects longer, reach for them
more, and are more likely to mouth the objects
 Cultural Variations: mothers in developing countries tend to
stimulate their infants’ motor skills more than mothers in
more modern countries
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18.  Sensation: occurs when information interacts
with sensory receptors (eyes, ears, tongue,
nostrils, and skin)
 Perception: the interpretation of what is sensed
 Ecological View: we directly perceive
information that exists in the world around us
 The perceptual system selects from the rich
information provided by the environment
 Perception enables interaction with, and adaptation
to, one’s environment
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19.  $$ Affordances: When we sense information
from the environment, we are given the
opportunity to interact with the environment
 Eleanor and James Gibson
 What affordances can infants or children detect
and use?
▪ Children become more efficient at discovering and
using affordances through perceptual development
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20.  $$ Visual Preference Method: the studying of
whether an infant can distinguish between two
objects is done by measuring the length of time the
infant looks at an object.
 Habituation: decreased responsiveness to a
stimulus after repeated presentations
 Dishabituation: recovery of a habituated response
after a change in stimulation
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21.  Newborn’s vision is about 20/600 (an object 20
feet away appears as if it were 600 feet away)
 Bythe age of 6 months, vision is 20/100 or
better
 Vision approximates that of an adult by the infant’s
first birthday
 Infants show an interest in human faces soon
after birth
 The way they gather information about the visual
world changes rapidly with age
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22.  Perceptual
Constancy: sensory stimulation is
changing but perception of the physical world
remains constant
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23.  $$ Two types of Perceptual Constancy
 Size Constancy: recognition that an object remains
the same even though the retinal image of the object
changes
▪ Babies as young as 3 months show size constancy
▪ Continues to develop until 10 or 11 years old
 Shape Constancy: recognition that an object remains
the same shape even though its orientation to us
changes
▪ 3-month-olds show shape constancy, but not for irregularly
shaped objects
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24.  Eleanor Gibson and Richard Walk studied
development of depth perception using a
“visual cliff”
 Infants 6-12 months old can distinguish depth
 Infants 2-4 months old show heart rate difference when
placed on deep side of cliff
 Infants develop binocular depth cues by about 3-4
months of age
 $$Stereoacuity: Fine-detail depth
perception
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25.  Fetuses can hear and learn sounds during
the last two months of pregnancy and can
recognize their mother’s voice at birth
 Newborns:
 Cannot hear soft sounds as well as adults
 Are less sensitive to pitch
 Are fairly good at determining the location of a
sound
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26.  Touchand Pain: newborns respond to touch
and can feel pain
 Smell: newborns can differentiate odors
▪ Preference for mother’s smell by 6 days
 Taste:
sensitivity to taste may be present
before birth
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