Chapter 3

• Dramatic increase in weight and height over first 2 years of life:

  • height: 75% increase
  • weight: quadrupled
• Cephalocaudal trend: the direction of development from head to toe
• Proximodistal trend: center outward growth (arms grow ahead of hands and feet)
• Synaptic pruning: brain removes neurons and synapses that it does not need
• Myelination: The process of insulating the axon with myelin sheaths. Speeds up the transmission of nerve impulses.
• Lateralization: The tendency for the left and right hemispheres of the brain to specialize in different functions.
• Neuroconstructivism: theory of the relation between brain development and psychological (mostly cognitive) development.

  • emphasizes bidirectional influence between biological processes and environmental experiences
• Brain development after birth:

  • cortex continues to develop
  • neurons increase in size and become more complex
  • synaptogenesis influenced by experience
  • myelination increases until adolescence
  • increase in connections between brain regions
• Various parts of the brain develop on different schedules:

  • brainstem is fully functional at birth
  • cerebral cortex is not fully functional at birth
  • prefrontal cortex develops last
• Benefits of breastfeeding:

  • weight gain
  • reduced risk of obesity
  • reduced risk of sudden infant death syndrome
  • fewer gastrointestinal infections
  • fewer lower respiratory tract infections
• When should mothers not breastfeed?

  1. Infected with AIDS or any other infectious disease that can be transferred through milk
  2. Has active tuberculosis
  3. Is taking any drug that may not be safe for the infant
• Reflex: built-in, automatic reactions to stimuli. Allow infants to respond adaptively to their environment before they have had the opportunity to learn

  • most disappear at a certain age
  • assessment of reflexes one to determine if there is a neurological deficit
• Motor skills as a dynamic system:

  • action is motivated by perception
  • increasingly complex systems of action with each skill
  • development of motor skills does not follow a fixed sequence and is not the unfolding of a genetic blueprint
• 4 factors in each new skill:

  1. CNS development
  2. Body's physical properties and movement capacity
  3. Child's motivation and goals
  4. Environmental supports
• Development of walking:

  1. Roll over
  2. Sit without support
  3. Crawling
  4. Standing
  5. Walking
• Principles of gross motor development:

  • infants do not transfer learning from one motor skill (crawling) to another (walking)
  • Acquisition of motor skills has consequences for cognitive and emotional development
• Reaching development:

  1. Pre-reaching
  2. Reaching (with two hands, then one)
  3. Ulnar grasp (adjust grip to object)
  4. Pincer grasp
• Sticky mittens experiment:

  • experience is important in the development of fine motor skills
  • sticky mittens training led to earlier grasp and manipulation of objects
• Methods of studying perceptual development:

  1. Visual preference method
  2. at which of two visual displays do infants look longer?
  3. Habituation/Dishabituation method
  4. Eye tracking
  5. measure eye movements
• 1. Habituation
  2. decrease in attention that occurs when a stimulus is presented repeatedly
  3. Dishabituation
  4. increase of attention to a new stimulus after decreased interest to an old stimulus
• Visual acuity: degree to which one can see fineness of detail

  • At birth: 20/600 acuity (can see clearly from 20 feet what an adult with normal vision sees clearly at 300 feet)
  • 2 weeks: 20/300
  • 6 months: 20/40
• Depth perception development:

  • birth to 1 month
  • sensitivity to motion cues
  • 2-4 months
  • sensitivity to binocular cues
  • 5-12 months
  • sensitivity to pictorial cues, wariness of heights, visual cliff
• Intermodal perception: the ability to perceive the spatial relationships between objects in different modes of perception
• Cataracts and perceptual development:

  • after inserting lenses, infants' visual acuity was that of a newborn, regardless of whether surgery took place at 1 week or 9 months
• Face perception development:

  • birth to 1 month
  • preference for simple, face-like features
  • 2-4 months
  • preference for a complex facial pattern over other, equally complex patterns
  • preference for mother's facial features over those of unfamiliar women
  • 5-12 months
  • more fine-grained discrimination of faces including the ability to perceive emotional expressions as organized wholes
• Perceptual narrowing: tuning of perceptual abilities based on experience

  • other race faces, monkey faces
• Key concepts of Piaget's theory:

  1. Scheme
  2. general, psychological structure
  3. Accommodation
  4. adjustment, change, modification of existing scheme
  5. Assimilation
  6. incorporation of new information into schemes
• Sensorimotor stage:

  • here and now, presymbolic
  • practical intelligence
  • coordinating sensory experiences with physical, motor actions
  • practical concepts
  • 6 substages
• Object permanence: the idea that objects continue to exist even when they are not visible.
• Object permanence substages:

  1. Passive expectations
  2. Recovery of partially hidden objects and anticipation of trajectories
  3. Retrieval of hidden objects and A-not-B error
  4. Failure to understand invisible displacements
  5. Success at invisible displacements
• Criticisms of Piaget's theory:

  • underestimating competence of object concept
  • Drawbridge study by Baillargeon
  • babies stare longer at the impossible event, understanding objects are substantial and permanent
  • violation of expectation
• Core knowledge approach: infants are born with domain-specific innate knowledge systems that are activated by specific stimuli
• Characteristics of human language:

  • arbitrariness
  • productivity
  • semanticity
  • displacement
  • rule-governed
• Phoneme: any of the perceptually distinct units of sound in a specified language that distinguish one word from another
• Kuhl's phoneme study: from birth to 6 months, infants can tell when sounds change most over time, no matter what language the syllables come from.