Newborns and Infants

EXAM 2

Brain Development

• Brain grows VERY rapidly

  • Triples in weight 1-2 years

• What’s happening in the brain?

  • Creating dendrites

  • Synaptogenesis

  • Myelination

• Most growth happens in the cortex

  • Prefrontal cortex is relatively under-developed

  • Motor areas develop before sensory areas

• Neuroplasticity: the brain’s ability to change, both physically and chemically, to enhance its adaptability to environmental change and to compensate for injury

Brain Development

Experience and pruning

• Specifics of brain structure and growth depend on genes and maturation, but even more on experience

• Early dendrite growth is called transient exuberance

• Unused dendrites whither (through pruning) to allow space between neurons in the brain, allowing more synapses and thus more complex thinking (sculpting)

Sleep

• Newborns sleep about 16-17 hours per day

• Comes in spurts (polyphasic)

• Sleep stages are longer and more predictable over time

  • 16 weeks: 6 continuous hours

  • 1 year: sleep through the night

• About half of infant sleep in REM sleep

  • More than double the typical proportion for adults

Sensory Development: Hearing

• Newborns hear at adult levels

• Fetus can hear around month 4-6

• Prefer mother’s voices and other familiar voices or sounds

• Attend more to “parent-ese”

Sensory Development: Touch

• Newborns are sensitive to touch, temperature, and pain at birth

• Kangaroo care

• Male circumcision is painful for babies: strong release of stress hormones, elevated heart rate, deoxygenation of blood

  • Males circumcised without anesthetic experience more pain and fear in response to childhood vaccinations

Sensory Development: Taste and Smell

• Certain taste preferences are innate, but can sometimes be shaped by exposure during pregnancy

• Preference for sweet flavors

• Newborns prefer the smell of their mother over people

Sensory Development: Vision

• Vision is the least-developed sense at birth

• Newborns have not yet developed a fovea and cannot see more than about 8 inches from their face

• Can only see vivd colors

• Eye movements are jerky at first but become smoother across time

• Depth perception develop around 6 month

Motor Development

• Motor development depends on a variety of factors

• Dynamic systems theories consider motivation a primary element of motor development

• As with prenatal development, motor development is cephalocadual and proximodistal

• Babies start with random movements that gradually become more intentional

• Get in the “ballpark” before refining movement

Windows of timing for baby motor milestones

• Sitting without support: 4 - 9 months

• Standing with assistance: 5 - 11 ½ months

• Hands and knees crawling: 5 - 13 months

• Walking with assistance: 6 - 13 ½ months

• Standing Alone: 7 - 16 months

• Walking alone: 7 ½ - 18 months

Motor Skills

• Gross motor = large muscle activity

• Fine motor = small, fine-tuned movements

  • Palmer grasp begins as a reflex and develops into a pincer grasp by end of first year