Chapter 3 Physical and Cognitive Development in Infancy

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Chapter 3 Physical and Cognitive Development in Infancy Powered By Docstoc
					Physical and Cognitive Development
in Infancy
     CHAPTER 3
Physical Growth and Development in
   Head
     large relative to the rest of the body
     flops around uncontrollably
   Infant becomes capable of
     Rolling   over
     Sitting
     Crawling
     standing
     stooping
     climbing
     usually   walking
The First Year
 Average North American newborn -- 20 inches
  long; 7½ pounds
 Most newborns lose 5 to 7 percent of their
  body weight adjusting to feeding
 They double their birth weight by the age of 4
  months; nearly triple it by their first birthday
 Infants grow about 1 inch per month during the
  first year
From Age 1 to 2 Years
   At 2 years of age, children weigh
    approximately 26 to 32 pounds
     gaining a quarter to half a pound per month
     attain about one-fifth of their adult weight

   At 2 years, the average child is 32 to 35
    inches tall
     nearly   half of their eventual adult height
 The Brain
 Cerebral cortex covers the forebrain like a
  wrinkled cap
 Two halves, or hemispheres, based on ridges
  and valleys in the cortex
 Lateralization -- specialization of function in
  one hemisphere or the other
     Example:   Spatial ability
   Parts of the neuron
     Axon carries signals away from the cell body
     Dendrites carry signals toward it
     Myelin sheath -- a layer of fat cells -- provides
      insulation and helps electrical signals travel faster
      down the axon
     At the end of the axon are terminal buttons, which
      release chemicals called neurotransmitters into
     Synapses -- tiny gaps between neurons' fibers
     Transient exuberance
    Changes in Neurons
   The infant’s brain is literally waiting for experiences to
    determine how connections are made
   Experience enhances brain development
       Experience-expectant     brain growth
                Examples: Maturation, eating, sensory
       Experience-dependent      brain growth
                Examples: Language, siblings, parent interaction
Changes in Regions of the Brain

 Both heredity and environment influence
  synaptic overproduction and subsequent
 Pruning -- unused connections are replaced by
  other pathways or disappear
 Prefrontal cortex -- the area of the brain
  where higher-level thinking and self-regulation
   Considerable individual variation in how much
    infants sleep
     typicalnewborn sleeps 16 to 17 hours a day
     preferred times and patterns of sleep also vary

   Infants spend a greater amount of time in REM
    (rapid eye movement) sleep
     by3 months of age, the percentage of time in REM
     sleep decreases
 Sudden infant death syndrome (SIDS) --
  condition that occurs when infants stop
  breathing, usually during the night, and die
  suddenly without an apparent cause
 SIDS is the highest cause of infant death in the
  United States
     Risk   of SIDS is highest at 2 to 4 months of age
    Risk Factors for SIDS
 SIDS decreases when infants sleep on their backs
 More common in low birth weight infants

 Infants who are passively exposed to cigarette
  smoke are at higher risk
 More frequent in infants who sleep in
  soft bedding or use a pacifier when they go to
Benefits of Breast Feeding
   Appropriate weight gain and lowered risk of
    childhood obesity
   Fewer allergies
   Prevention or reduction of diarrhea, respiratory
    infections, bacterial and urinary tract infections, and
    otitis media
   Denser bones in childhood and adulthood
   Reduced childhood cancer and reduced incidence of
    breast cancer in mothers and their female offspring
   Lower incidence of SIDS

       When should a mother not breast feed ?
Nutritional Needs
 Nutritionists recommend that infants consume
  approximately 50 calories per day for each
  pound they weigh
 This is more than twice an adult’s requirement

  per pound
 Many U.S. parents are feeding their 4- to 24-
  month-old babies too few fruits and
  vegetables, and too much junk food
   Reflexes -- built-in reactions to stimuli – automatic,
   Allow infants to respond adaptively to their
       Examples: Rooting and sucking, Moro or startle reflex,
        coughing, sneezing, blinking, shivering, and yawning
Gross Motor Skills
   Skills that involve large-muscle activities
     Sitting with support -- 2 months
     Sitting upright without support -- 6 to 7 months of
     Pull themselves up and hold on to a chair -- 8
     Stand alone – 10 to 12 months
Gross Motor Development in the Second
 Toddlers become more mobile
 13–18 months
     can pull a toy attached to a string
     use their hands and legs to climb up a number of steps

   18–24 months
     toddlers can walk quickly or run stiffly
     walk backwards without losing their balance
     stand and kick a ball without falling and stand and throw a
     jump in place
Fine Motor Skills
   Finely tuned movements
     anything   that requires finger dexterity
 At birth, infants have very little control over
  fine motor skills
 During the first two years of life, infants refine
  how they reach and grasp
     Perceptual-motor  coupling is necessary for the
      infant to coordinate grasping
     Experience plays a role in reaching and grasping
Sensory and Perceptual Development

   Sensation occurs when information interacts
    with sensory receptors -- the eyes, ears, tongue,
    nostrils, and skin
     Example:   Everything…
   Perception is the interpretation of what is
     Example:   Mommy, foods, HOT!
Studying the Infant’s Perception
   Visual Preference Method -- Infants look at different
    things for different lengths of time
   Orienting response -- to determine if an infant can
    see or hear a stimulus
   Habituation -- decreased responsiveness to a stimulus
    after repeated presentations of the stimulus
       Examples: Pacifier, holding hands, football game?
   Dishabituation -- is the recovery of a habituated
    response after a change in stimulation
       Example: sleeping in the car…
    Visual Acuity and Color
 Newborn’s vision is estimated to be 20/600 on
  the well-known Snellan eye examination chart
 By 6 months of age -- vision is 20/40 or better

 By about the first birthday, the infant’s vision
  approximates that of an adult
 By 8 weeks, possibly even by 4 weeks, infants
  can discriminate among some colors
   (Banks & Salapatek, 1983; Aslin & Lathrop, 2008)
 Perception of Pattern and Depth

   Infants prefer to look at a normal human face
    rather than one with scrambled features
     Can       babies detect attractiveness?
 They prefer to look at a bull’s-eye target or
  black-and-white stripes rather than a plain
 Depth perception -- visual cliff
     Infants  develop the ability to use binocular (two-
        eyed) cues to depth by about 3 to 4 months of age
(Gibson & Walk, 1960)
Hearing, Touch, and Pain

 Prenatally at 7 months, infants can hear sounds
  such as mother’s voice and music
 Immediately after birth, infants cannot hear soft
  sounds or pitch as well as adults do
 Newborns respond to touch and feel pain

 Infants also display amazing resiliency

     Within several minutes after the circumcision surgery
     (which is performed without anesthesia), they can
     nurse and interact in a normal manner with their
  Smell and Taste
   Newborns can differentiate among odors
     Example:             Mom vs. Dad
 Sensitivity to taste might be present even
  before birth
 At only 2 hours of age, babies made different
  facial expressions when they tasted sweet, sour,
  and bitter solutions
 At about 4 months of age, infants begin to
  prefer salty tastes, which as newborns they had
  found to be aversive
(Windle, 1940; Rosenstein & Oster, 1988; Harris, Thomas, & Booth, 1990)
Piaget’s Theory of Cognitive
   Piaget thought we build mental structures that help us
    to adapt to the world
   Adaptation involves adjusting to new environmental
  Processes of Development
    Developing brain creates schemes, which are actions or mental
     representations that organize knowledge
    Assimilation -- children use their existing schemes to deal with
     new information or experiences
       Examples: Banging, chewing, dropping, hot dirt, parties
    Accommodation -- children adjust their schemes to take new
     information and experiences into account
       Examples: no cats!, get splashed

         Examples: Juice, in the hoop, “Bye, Bye”

(Lamb, Bornstein, & Teti, 2002)
Equilibrium and Disequilibrium
   Cognitive conflict -- disequilibrium
       the child is constantly faced with inconsistencies and
        counterexamples to existing schemes
   An internal search for equilibrium creates motivation
    for change
       the child assimilates and accommodates, develops new
        schemes, and organizes and reorganizes old and new
Sensorimotor Stage
   Sensorimotor intelligence: From birth to 2 years:
    infants construct an understanding of the world by
    coordinating sensory experiences (such as seeing and
    hearing) with physical actions
Cognitive Development
   Sensorimotor stage
     Primary   circular reactions
       Stage   1: Stage of reflexes
                Examples: Sucking, arms up!
       Stage   2: First acquired adaptation
                Examples: Bottle vs. pacifier, crying
Sensorimotor Stage
   Secondary circular reactions
     Stage   3: Make interesting events last
                 Examples: Rattle on table, bouncing, Peek-a-boo, ripping
     Stage4: New adaptation and anticipation or “The
      means to the end”
                 Examples: The “drop game,” books, Exersaucer, feeding
                  Mommy, size
       Object    permanence
                 Examples: Mommy, keys, which hand?
Object Permanence
   One of the infant’s most important accomplishments
   Watch an infant’s reaction when an interesting object
    disappears. If the infant searches for the object, it is inferred
    that the baby knows it continues to exist
   A-not-B error is the term used to describe the tendency of
    infants to reach where an object was located earlier rather
    than where the object was last hidden
Sensorimotor Stage
   Tertiary circular reactions
       Stage 5: New means through active experimentation
                      Example: Cabinet, water
         Little   scientist
                      Examples: Beans, vacuum
       Stage 6: Mental representations
                      Example: Little cowboy…, bandaid
         Deferred       imitation
                      Examples: DVD, spanking
         Make-believe         play
                      Examples: Dolls, trucks, “Sip…” “Bite…”
Learning, Remembering, and
   Infants can learn through operant conditioning
       Examples: Reading a book, building a castle, using signs
   Attention is the focusing of mental resources on select
    information and improves cognitive processing on
    many tasks
   Joint attention involves individuals focusing on the
    same object or event and involves:
      The ability to track another’s behavior

      One person directing another’s attention

      Reciprocal interaction
Learning, Remembering, and
   Meltzoff (2007) concludes that infants don’t blindly
    imitate everything they see and often make creative
   He argues that beginning at birth there is an interplay
    between learning by observing and learning by doing
   Critics say the newborns simply engage in automatic
    responses to a stimulus
Learning, Remembering, and
   Memory involves the retention of information over time
   Some infants as young as 2 to 6 months can remember
    some experiences through 1½ to 2 years of age
   Implicit memory refers to memory without conscious
   Explicit memory refers to conscious memory of facts
    and experiences
   Infantile or childhood amnesia -- few memories before
    age 3
Language Development
 Language -- a form of
  communication—whether spoken, written, or
  signed—that is based on a system of symbols
 All human languages have some common
     Rules  describe the way the language works
     Infinite generativity -- the ability to produce an
      endless number of meaningful sentences using a
      finite set of words and rules
(Berko Gleason, 2009)
Key Milestones in Language Development

   Babies' sounds and gestures go through this sequence
    during the first year
     Crying: can signal distress, but there are different types of
      cries that signal different things
     Cooing: about 1 to 2 months, gurgling sounds that are
      made in the back of the throat and usually express pleasure
      during interaction with the caregiver
     Babbling: In the middle of the first year, babies babble --
      strings of consonant-vowel combinations, such as “ba, ba,
      ba, ba”
     Gestures: Infants start using gestures, such as showing and
      pointing, at about 8 to 12 months of age
          Example: simple signs (operant conditioning)
Recognizing Language Sounds
 First words occur between 10 to 15 months
  (average is 13 months)
 Overextension -- the tendency to apply a word

  to objects that are inappropriate for the word’s
 Underextension -- the tendency to apply a
  word too narrowly

   Examples: Duck, Shoes, Train
Two-Word Utterances
   Occurs by the time children are 18 to 24
    months of age
     “Big

     “Where cat?”

   Telegraphic speech is the use of short, precise
    words without grammatical markers such as
    articles, auxiliary verbs, and other connectives
     “Mommy  hold you”
     “No mo’ monkey jump bed…”
Biological Influences
   The ability to use language requires vocal apparatus
    as well as nervous system capabilities
   Brain regions predisposed for language
     Broca’s area -- an area in the left frontal lobe of
      the brain involved in producing words
     Wernicke’s area -- a region of the brain’s left
      hemisphere involved in language comprehension
   Aphasia -- a loss or impairment of language
    processing as a result of damage to brain
Biological Influences
   Language Acquisition Device (LAD) -- Humans
    are biologically prewired to learn language at
    a certain time and in a certain way and to
    detect the various features and rules of
Environmental Influences
   Behaviorists opposed Chomsky's LAD hypothesis
       Stated that language was nothing more than chains of
        responses acquired through reinforcement
   The behavioral view is no longer considered a viable
    explanation of how children acquire language
       Example: Not all imitation: “I runded…”
   Language is not learned in a social vacuum
       Most children learn at a very early age
Environmental Influences
   Vocabulary development is linked to the family’s socioeconomic
    status and the type of talk that parents direct to the child
   Compared to professional parents, parents on welfare:
       Talked much less to young children
       Talked less about past events
       Provided less elaboration
   Child-directed speech is language spoken in a higher pitch
    than normal, using simple words and sentences
   Other strategies include recasting, expanding, labeling

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