THE PHYSICAL SELF: DEVELOPMENT OF THE BRAIN, THE BODY, & MOTOR SKILLS

1. THE PHYSICAL SELF: DEVELOPMENT OF THE BRAIN, THE BODY, & MOTOR SKILLS

2. Physical Development • In the 1st few months, children grow nearly an ounce each day and an inch each month • First two years marked by rapid growth. • Doubling their birth weight by 4 to 6 months. • Tripling their birth weight by the end of their 1st yr. of life (21 pounds). • Growth is rapid but irratic. • Children may stagnate in growth for days or even weeks before experiencing a growth spurt (over centimeter in a day). • By age 2, toddlers already have half their eventual adult height and have quadrupled their birth weight to some 30 pounds • From age 2 until puberty, children gain about 2 to 3 inches in height and 6 to 7 pounds in weight each year

3. Changes in Body Proportions • A newborns head is 70% of its eventual adult size and represents ¼ of the infants length • Cephalocaudal Development • Trunk grows fastest during the 1st year • At 1yr, the head accounts for 20% of total body length • Proximodistal Development • During prenatal development, chest and internal organs form 1st followed by arms & legs and then hands & feet • Throughout infancy and childhood, arms & legs continue to grow faster than hands and feet

4. Skeletal Development • Skeletal structure starts as soft cartilage during prenatal and gradually hardens (Ossification). • Discuss Epiphysis (growth centers where new cartilage is formed. • This is why infants cannot initially set up or balance themselves • Neonates skull consists of several soft bones that can be compressed to allow for the passing thru cervix and birth canal • Skull bones are separated by 6 soft spots called fontanelles • By age 2, these soft spots solidify leaving smaller seams (sutures) which allow the skull to expand as the brain grows larger • Bones in ankle/feet and wrist/hand increases as child matures • Skeletal age is often determined thru x-ray of hands/feet to examine bone density and interconnections • Girls mature faster than boys (This may explain why girls tend to be healthier and more resistant to illnesses) • African-American children develop faster than Caucasian children --At birth, girls are 4 to 6 wks ahead of boys regarding skeletal maturity; by age 12, the maturity gap widens 2 full years • Bones in skeletal system grow and harden at different rates • Skull and hands mature first; leg bones reach mature development in late teens • In general, mature skeletal development occur by age 18

5. Skeletal Development Cont. • While children grow and develop at different rates, the best predictor of maturity is skeletal development.

6. Presence of Teeth • In general, infants get their first tooth around 6 months to a year. However, • There are differences as a function of gender and ethnicity. • Because girls mature faster than boys and African-Americans mature faster than Caucasian infants. Both groups tend to get their first tooth earlier • In some cases, children are born with their first tooth • By age 2, children generally have all 20 of their primary teeth

7. Muscular Development • Neonates are born with all the muscle fibers they will ever need • At birth, muscle tissue is 35% water (later replaced by nutrients and salts); accounting for 18 to 24% of the babies weight • Muscle development proceeds in Cephalocaudal and Proximodistal manner. Muscles in head and neck maturing faster than muscles in trunk and limbs • With growth spurts in muscles, boys make significant gains in strength and size • Variations in physical growth depends on genes and cultural practices • People from Asia, South America, & Africa tend to be smaller than North America, North Europe, and Australia

8. Development of the Brain • Brain grows from 25% of its adult weight at birth to 75% of adult weight by age 2. • The last 3 prenatal months and the first 2 years after birth are termed the period of the brain growth spurt (more than half of brains weight added at this time). • The brain function consists of a trillion specialized cells that transmit exectrical/chemical signals. • Synapses • Neurons—100 to 200 billion cells produced in neural tube during 2nd trimester • Glial—2nd type of nerve cell that provide nourishment and encasement to neurons

9. Cell Differentation and Synaptogenesis • Neurons assume specialized functions as they migrate to certain areas of the brain • Synaptogenesis • As neurons become more specialized, the interconnections forms to provide for reasoning and problem-solving • Through appropriate stimulation, children develop appropriate synapses. Neurons that fail to interconnect (about half) fail to survive—This is the pruning process • An infant’s brain exhibits high plasticity (capability of change and adaptation). As we get older, brain cells become more rigid and inflexible • Much research seems to suggest that early experiences (both in humans and animals) play a vital role toward brain formation. • Maximal development for certain talents are related to sensitive periods where environmental stimulation is necessary for brain formation

10. Cerebral Lateralization • The brain divides into left and right hemispheres. • Left side/brain controls right side/body and contains centers for speech, hearing, verbal memory, decision making, language, and expression of positive emotions • Right side/brain control left side of body and contains centers for processing visual-spatial information, nonlinguistic sounds such as music, touch sensations, and expression of negative emotions • 90% of adults are left hemisphere dominant • Brain lateralization was initially thought to occur by end of puberty. • Recent research identifies prenatal lateralization • Brain lateralization/plasticity remain quite high for the first 3 years of life. Gradually diminishes with age.

11. Motor Development • By the end of the first month, most babies can • Lift their chins while lying flat on stomach • Lift their chests • Reach for objects • Roll over and sit up with some support. • Motor develop has been used as a predictor for long-term developmental outcomes in the past • More recent research suggest that variations in motor gains do not significantly predict long-term developmental outcomes • (See Table 5.1 on page 152 for sequence of motor development).

12. Explanations for Sequencing and Early Timing of Early Motor Development • Maturational viewpoint: Biological/genetic blueprint determines the sequence of nervous and muscular system development (Downward/Outward). • Cross cultural studies have indicated consistent developmental patterns. • Twin study in which one child allowed to practice motor skills while the other not allowed to practice. Upon testing, no long-term significant adjustment outcomes. • Experiential viewpoint: Experience/practice becomes vital towards facilitating motor development. • Several studies have noted cultural differencies in motor development due to child rearing practices. • Iranian study (children spend 1st 2 yrs lying on backs in cribs/feeding, little play—motor development significantly impacted. Delayed in talking, sitting up, walking. 15% of the 3 to 4 year olds could walk. • Dynamical Systems Theory viewpoint: Motor development is an active reorganization of previously mastered capabilities that are adjusted due to environmental exploration and curiosity dev.

13. Goldfield Study (1989) • Infant’s emergence to crawling around 7 to 8 months. • Regularly turned and raised their heads to interesting sights and sounds • Developed distinct schemes for reaching and grasping • Developed distinct schemes (leg thrust movements) to allow for greater mobility • Infants development is goal directed • While highly dependent of maturation and influenced by experiences, the child is actively navigating and engaging the environment and developing more complex schemes/talents in the process of constructing his/her understanding of the world

14. Fine Motor Development • Birth – 3 months • Innate and primitive reflexes (palmer grasp) evolve into more voluntary motor movements/reaching (around 2 months). • 3 months • Refined fine motor skills and improved grasping • Refined hand-eye coordination • 4-5 months • Refined ability to sit up and move their hands across their bodies. • Develop hand to hand movements during transferring of objects and development of ulnar grasp (grasping of objects by pressing fingers to palm. • 6 months • Pincer grasp develops (ability to use thumbs to counter the strength of fingers). • Refined grasping techniques facilitates changes in play and exploration. • Wheeled toys (once banged) are likely to be scooted; soft objects are likely to be squeezed.

15. Fine Motor Development Cont. • As children get older, greater development of fine motor skills. • Parents and teachers facilitate development thru play/creativity with crayons, blocks, markers, etc. • Kids have yet to master speed with fine and gross motor skills….Therefore, 2 to 3 yr olds may still have difficulty catching and throwing a ball.

16. Exploring the New Environment • As children develop greater awareness of their competencies, they are truly experiencing a new environment. • Children Explore….Parents Childproof. • Children on the move……..Parents in Pursuit. • Motor develop facilitates development across other domains • Children with greater mobility are better able to explore relationships with other people. • Greater confidence due in part to their ability to retreat when they feel appropriate. • Children explore people as well as objects.

17. Role of Nutrition in Infancy • Deficiencies in nutrition during infancy can permanently stunt development, particularly in brain functioning and development • Breast feeding remains the healthiest option for ensuring infants obtain proper nutrients. Advantages are as follows • Correct balance of fat and protein. Human milk have higher fat content/lower protein. Essential for brain development/ mylenization/ nervous system. • Nutritional Completeness. Human milk has all that a child needs (1st 6 months). If bottle feeding, you need iron supplementation • Protection against diseases. Breast feed babies develop greater resistance against disease. Receive antibodies from mom • Protection against malocclusions & tooth decay. • Digestibility. Different bacteria growth in body; less constipation and diarrhea • Smoother transition to solid foods. Breast fed babies make a smoother transition to solid foods. Due in part to a greater variety of experience in taste thru mother’s milk.

18. Nutrition/Breast feeding Cont. • Breast feeding declined in the United States from 1940’s to 1970’s. • The natural childbirth movement in the late 70’s brought a return to breast feeding in US. • Today, 2/3 of mothers breastfeed. • Generally practiced among the well-educated and middle social class mothers. • Babies, from poverty-strickened areas, who are breastfed are more likely to be healthy and survive their first year. • Babies breast fed exclusively for the first 6 months would save the lives of 1 million babies annually (Grant, 1995).