The First Two Years: Infant and Toddlers

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Part II
Chapter Five

• The First Two Years Infant and Toddlers

Body Changes Brain Development Senses and Motor
Skills Public Health Measures
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Adults dont change much in a year or two.
Their hair might grow longer, grayer, or
thinner they might be a little fatter or they
might learn something new. But if you saw
friends you hadnt seem for two years, youd
recognize them immediately.
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• By contrast, if you cared for newborn 24 hours a
  day for a month, went away for two years, and
  then came back,you might not recognized him or
  her, because the baby would have quadrupled in
  weight, grown taller by more than a foot, and
  sprouted a new head of hair.
• Behavior would have changed, too. Not much
  crying, but some laughter and fearincluding of
  you.

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• A year or two is not much compared with the 75
  or so years of the average life span. However,
  in two years newborns reach half their adult
  height, talk in sentences, and express almost
  every emotionnot just joy and fear but also
  love, jealousy, and shame.

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Biosocial Development
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Body Changes

• In infancy
• growth is fast
• neglect can be severe
• gain needs to be monitored
• health check-up need to include
• height, weight and head circumference

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Body Size

• rapid growth
• double their birth weight by the 4th month and
  triple by the 1st birthday
• physical growth slows in the 2nd year
• by 24 months weight is about 30 lbs, height about
  32-36
• these numbers are norms

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Body Size

• norms
• an average or standard for a particular
  population
• particular population
• a representative sample of North American infants
• percentiles
• a number that is midway between 0 and 100, with ½
  the children above it and ½ below it

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Body Size

• Weight increase in the early months is fat,
  providing insulation for warmth and nourishment
• Nourishment keeps the brain growing, if teething
  or illness interfere with eating
• When nutrition is temporarily inadequate, the
  body stops growing but not the brain
• this is known as a phenomenon called
  head-sparing

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Sleep

• Infants sleep about 17 hours or more a day
• Regular and ample sleep correlates with normal
  brain maturation, learning, emotional regulation,
  and psychological adjustment in school and within
  the family

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Sleep

• Over the first month the amount of time spent in
  each type or stage of sleep changes
• Newborns dream a lot, or at least they have a
  high proportion of REM sleep
• REM sleep
• rapid eye movement sleep is a stage of sleep
  characterized by flickering eyes behind closed
  lids, dreaming, and rapid brain waves

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Sleep

• Sleep Patterns can be
• affected by birth order
• first born typically receive more attention
• diet
• parents might respond to predawn cries with food,
  and/or play (babies learn to wake up night after
  night)
• child-rearing practices
• Where should infants sleep?
• co-sleeping or bed-sharing
• brain maturation

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Brain Development

• the newborns skull is disproportionately large
• large enough to hold the brain, which at birth is
  25 of the adult brain
• the neonates body is typically 5 of the adult
  weight
• by age 2 the brain is almost 75 of the adult
  brain weight
• the childs total body weight is only about 20
  of its adult weight

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Basic Brain Structures

• Neurons are one of the billions of nerve cells in
  the central nervous system, especially the brain.
• Located in the brain or in the brain stem
• the region that controls automatic responses,
  I.e., heartbeat, breathing, temperature, and
  arousal
• 70 of the neurons are in the cortex

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Basic Brain Structures

• The cortex is crucial for humans
• 80 of the human brain materials in the cortex
• in other mammals the cortex is proportionally
  smaller, and non-mammals have no cortex
• most thinking, feeling, and sensing take place in
  the cortex, although other parts of the brain
  join in.

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Basic Brain Structures

• Areas of the cortex specialize in particular
  functions
• visual
• auditory
• an area dedicated to the sense of touch for each
  body part
• regional specialization within the cortex occurs
  not only for motor skills and senses but also for
  aspects of cognition

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Basic Brain Structures

• Between brain areas, neurons are connected to
  other neurons by intricate networks of nerve
  fibers called axons and dendrites
• a neuron has a single axon and numerous
  dendrites, which spread out like the branches of
  a tree
• axons and neurons meet the dendrites of other
  neurons at intersections called synapses which
  are critical communication links within the brain

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Basic Brain Structures
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Basic Brain Structures

• Transient Exuberance and Pruning
• The fivefold increase in dendrites in the cortex
  occurs in the 24 months after birth, with about
  100 trillion synapses being present at age 2
• The expanded growth is followed by pruning in
  which unused neurons and misconnected dendrites
  atrophy and die
• Synapses, dendrites, and even neurons continue to
  form and die throughout life, though more rapidly
  in infancy than at any other time

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Basic Brain Structures

• Experience Shapes the Brain
• brain structure and growth depends on genes and
  experiences
• some dendrites wither away because they are
  underused no experiences have caused them to
  send a message to the axons of other neurons.

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Basic Brain Structures

• Stress and the Brain
• the role of experience in brain development
  begins when the brain produces cortisol and other
  hormones in response to stress, which happen
  throughout life

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Basic Brain Structures

• Experience-expectant refers to brain functions
  that require certain basic common experiences,
  which an infant can be expected to have in order
  to develop normally
• Experience-dependent refers to brain functions
  that depend on particular, variable experience
  and that therefore may or may not develop in a
  particular infant

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Basic Brain Structures

• Basic, common experiences must happen for normal
  brain maturation to occur
• in contrast, dependent experiences might happen.
  Because of them, one brain differs from another
• experience varies language babies hear or how
  their mothers reacts to frustration
• all people are similar, but each person is
  unique, because of early experiences

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Basic Brain Structures

• The last part of the brain to mature is the
  prefrontal cortex
• The area for anticipation, planning, and impulse
  control
• Virtually inactive in early infancy
• Gradually becomes more efficient over the years
  of childhood and adolescence

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Basic Brain Structures

• Implications for Caregivers
• Early brain growth is rapid and reflects
  experience
• caressing a newborn,
• talking to a preverbal infant
• showing affection
• are essential to develop that persons full
  potential

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Basic Brain Structures

• The human brain is designed to grow and adapt
• some plasticity is retained throughout life
• the brain protects itself from overstimulation
• babies adjust to understimulation

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Basic Brain Structures

• THINK LIKE A SCIENTIST
• Plasticity and Orphans

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Senses and Motor Skills

• Sensorimotor stage
• cognition develops from the senses and motor
  skills
• depends on sensory experiences and early movement
• within hours of birth vital organs are
  functioning, assessing basic senses and motor
  responses

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Sensation and Perception

• All the senses function at birth
• open eyes, sensitive ears, and responsive noses,
  tongues, and skin
• Very young babies attend to everything
• Infants dont focus on anything in particular
• To about age one taste is the primary way humans
  learn about objects

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Sensation and Perception

• Sensation is the response of a sensory system
• eyes, ears, skin, tongue, nose
• when it detects a stimulus

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Sensation and Perception

• Perception is the mental processing of sensory
  information
• the brain notices and processes a sensation
• when the brain interprets a sensation
• Infants brains are attuned to experiences that
  are repeated, striving to make sense of them

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Senses and Motor Skills

• Hearing
• Hearing is acute at birth
• Certain sounds trigger reflexes
• Sudden noises startle newborns
• Rhythmic sounds soothe them and put them to sleep

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Senses and Motor Skills

• Seeing
• At birth vision is the least mature
• The infant eyes are sensitive to bright light
  even though the eyes open in mid-pregnancy
• Newborns are legally blind they can only see
  objects 4 30 away

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Senses and Motor Skills

• Seeing
• At two months infants look more intensely at
  faces and often smile
• At three months infants look more closely at the
  eyes and mouth
• The ability to focus the two eyes in a
  coordinated manner in order to see one image is
  known as binocular vision

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Senses and Motor Skills

• Tasting, Smelling and Touching

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Senses and Motor Skills

• Tasting, Smelling and Touching
• At birth the senses of taste, smell and touch
  function and rapidly adapt to the social world
• As infants learn their caregivers smell and
  touch (handling) they relax and cuddle
• Over time infants become responsive to whose
  touch it is and what it communicates

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Senses and Motor Skills

• Early sensation seems to have two goals
• Social interaction
• To respond to familiar caregivers
• Comfort
• To be soothed amid the disturbances of infant
  life

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Senses and Motor Skills

• Motor Skill is the learned ability to move some
  part of the body, from a large leap to a flicker
  of the eyelid.
• (

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Senses and Motor Skills

• Newborns have many reflexes, some of which
  disappear with maturation (a reflex is an
  involuntary response to a particular stimulus

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Senses and Motor Skills

• Reflexes
• three sets are critical for survival
• that maintain oxygen supply
• that maintain constant body temperature
• that manage feeding

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Senses and Motor Skills

• Gross Motor Skills are physical abilities
  involving large body movements (gross meaning
  big)
• walking
• jumping
• Walking progress
• from reflexive,
• to hesitant
• to adult-supported stepping
• to a smooth coordinated gait

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Senses and Motor Skills

• Gross Motor Skills
• Three factors combine to allow toddlers to walk
• muscle strength
• brain maturation within the motor cortex
• practices

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Senses and Motor Skills

• Fine Motor Skills are physical abilities
  involving small body movements, especially of the
  hands and fingers (fine in this text means
  small)
• drawing
• picking up a coin

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Senses and Motor Skills

• Ethnic Variation
• healthy infants develop skills in the same
  sequence
• they vary in the age at which they acquire them

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Senses and Motor Skills
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Senses and Motor Skills

• Genes are only a small part of most ethnic
  differences
• Cultural patterns of child rearing can affect
  sensation, perception, and motor skills

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Public Health Measures

• 8 billion children were born between 1950 2005
• 2 billion died before age 5
• Deaths could be twice this if not for
• Child care
• Preventive care immunization
• Clean water
• Adequate nutrition
• Medial treatment, etc.

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Public Health Measures

• Immunization is a process that stimulates the
  bodys immune system to defend against attack by
  a particular contagious disease (immunization
  acquired either naturally, by having the disease
  or though vaccination)

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Public Health Measures

• Sudden Infant Death Syndrome (SIDS)
• die unexpectedly in their sleep
• No apparent cause of death
• 1990 in the U.S., 5000 babies died of SIDS, 1 in
  800

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ISSUES AND APPLICATONS

• Back to Sleep

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Nutrition

• Breast is Best
• Good nutrition starts with mothers milk
• Colostrum, a thick, high-calorie fluid secreted
  by the womans breast at the birth of a child.
• About 3 days later the breast begins to produce
  milk
• Breast fed babies are less likely to get sick

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Nutrition

• Malnutrition
• protein-calorie malnutrition is a condition in
  which a person does not consume sufficient food
  of any kind
• the deprivation can result in several illnesses,
  severe weight loss, and sometimes death
• to measure a childs nutritional status, compare
  weight and height with the "norms"