physical development in infancy

• Cephalocaudal Pattern


  Sequence in which the earliest growth always occurs from the top downward: Head to tail, Lower part of body grows later than the head
• Proximodistal Pattern


  Sequence in which growth starts in the center of the body and moves toward the extremities: Center to far, Head, trunk → arms → hands and fingers
• Height & Weight


  • Height increases 50% by age 1, Weight doubles by 5 months, triples by 1 year, During the 1st year of life, the greatest height & weight increases occur, but children continue to grow through infancy & toddlerhood
• Changes in Body proportion

  • Newborn head is 25% of own body length, Head length is 40% of mature length at birth, Adult head is only ~15% of body length
• Sleep


  Typical newborns sleep 16-17 hours per day, Babies average much more REM sleep than do older children or adults, REM sleep may provide infants with added self-stimulation, REM sleep may also promote brain development
• Reflexes


  Built-in reactions to stimuli that generally carry survival mechanisms
• Types of Reflexes


  • Rooting reflex
  • Sucking reflex
  • Grasping reflex
  • Moro reflex
  • Babinski reflex
  • Walking reflex
  • Tonic neck reflex
• Rooting reflex


  When the infant's cheek is stroked, the infant will turn its head to the side that was touched. Disappears 3-4 months after birth
• Sucking reflex


  Automatically suck an object placed in its mouth. Becomes conscious effort around 3-4 months of age
• Grasping reflex


  Infant's hands close around anything that touches the palms. Disappears 3-4 months after birth
• Moro reflex


  Automatic arching of back and wrapping of arms to center of body. Disappears 4-6 months after birth
• Babinski reflex


  When sole of foot stroked, infants' toes fan out and foot turns in. Disappears 9-12 months after birth
• Walking reflex


  When the infant is held under the arms and with the feet in contact with a surface, the infant moves feet as if to walk. Disappears 3-4 months after birth
• Tonic neck reflex


  When the child's head is turned to the side, the arm on that side will straighten and the opposite arm will bend. Present at one month of age and disappears at around four months
• Gross Motor Skills


  • Skills that involve large-muscle activities like rolling over, sitting upright, walking
• Fine Motor Skills


  • Involve finely tuned movements like reaching and grasping
• Sensation


  Occurs when information interacts with sensory receptors (eyes, ears, tongue, nostrils, and skin)
• Perception


  The interpretation of what is sensed
• Visual Perception


  Newborn's vision is about 20/600 (an object 20 feet away as if it were 600 feet away). By 6 months, vision is 20/100 or better. By first birthday, vision approximates that of an adult
• Visual Preference


  Infants show an interest in human faces soon after birth
• Depth Perception


  Infants of different ages are tested on a table-top device that simulates a drop off (or cliff) of about 4 feet. 1 month: no change in heart rate, no perception of depth. 2 months: decrease in heart rate, sign of interest. 9 months: increase in heart rate, fear response to perception of depth and ability to fall
• Hearing


  Infants hear from the time they are born, and even before! They are more sensitive than adults to high and low frequencies but not to the middle ranges
• Smell


  Newborns can differentiate odors and show preference for mother's smell by 6 days
• Tasting


  Infants react to unpleasant tastes
• Touch and Pain


  Newborns respond to touch and can feel pain
• Schemes


  Actions or mental representations that organize knowledge. Behavioral schemes in babies, mental schemes in older children
• Schemes are organized through two processes: organization and adaptation (assimilation and accommodation)
• Organization

  Grouping isolated behaviors into a higher-order or arranging items into categories
• Assimilation


  Occurs when children use their existing schemes to deal with new information or experiences
• Accommodation


  Occurs when children adjust their schemes to take new information and experiences into account
• Equilibration


  A mechanism that Piaget proposed to explain how children shift from one stage of thought into the next. Involves resolving cognitive conflict (disequilibrium) to reach a new balance (equilibrium) of thought
• Piaget's Stages of Development

  • Sensorimotor
  • Preoperational
  • Concrete Operational
  • Formal Operational
• Sensorimotor Stage Sub-Stages


  • Simple reflexes (Birth - 1M)
  • First habits & primary circular reactions (1 - 4M)
  • Secondary circular reactions (4 to 8M)
  • Coordination of secondary circular reactions (8-12M)
  • Tertiary circular reactions, novelty & curiosity (12-18M)
  • Internalization of schemes (18-24M)
• Simple Reflexes


  First month after birth, including rooting, sucking, and grasping reflexes
• First Habits & Primary Circular Reactions

  1. 4 months of age. Habits are actions involving the infant's own body that are learned by trial and error. Primary circular reactions are repetitive actions to recreate an event that initially occurred by chance
• Secondary Circular Reactions


  1. 8 months of age, infant becomes more object-oriented but schemes are not intentional or goal-directed
• Coordination of Secondary Circular Reactions

  1. 12 months of age, actions are more outwardly directed and intentional, infants put two schemes together to solve problems
• Tertiary Circular Reactions, Novelty & Curiosity


  12-18 months of age, repetition with variation leads to new outcomes, infants intrigued by properties of objects
• Internalization of Schemes


  18-24 months of age, infant develops ability to use primitive symbols