Physical Development in Infancy

Development inside the womb and out Cepahalocaudal development – Proximodistal development –

Physical development Principle of hierarchical integration – i.e., learning how to hold pencil precedes writing Principle of independent systems – i.e., height and weight can be independent of each other

Height and Weight Infants double their birthweight by four months of age, tripled it by their first birthday, & grow: By 2 years of age, infants weigh approximately 26 to 32 pounds & have reached:

The Brain Child is born with: Neuron - nerve cell that processes information at cellular level. Dendrites receive information from other neurons, muscle or glands Axon transmits information Myelin sheath speeds information transmission Axon ends are the terminal buttons of the neuron

The Brain’s Development Between 10 and 26 weeks, the neuron connections are generated at 250,000 per minute Following this cells move to appropriate locations in brain in process called migration Finally, they are ready for collecting & processing information, known as cell elaboration

Early Experience and the Brain Scientific research on animals & humans who have suffered brain damage, tells us that brain produces trillions of cells in early development which cannot possibly be used Animals reared in richly-stimulated environments have more neuronal connections than those reared in restricted environments Implication is children who are given a rich environment very early on, will develop greater neuronal connections for later use There is some skepticism of this belief

Marion Diamond’s research Maturation-genetic map – cannot alter this However, this does not mean that environment cannot affect anything

Marion Diamond Demonstrated that an enriched environment: An impoverished environment decreases cell weight, may lead to a loss of cells and the number of dendrites will be reduced (synaptic pruning)

Neural plasticity and critical periods If the neural growth is inhibited: Does not affect the person with sensitive periods, but critical periods it does

Infant States States of consciousness or levels of awareness that characterize individuals. Some states are: REM (rapid eye movement) sleep active sleep without REM indeterminate sleep drowsy inactive alert active awake crying

Nutrition Growing research supports nutrition programs for infants which will supply needed nutrients for proper physical, cognitive & emotional development Breast/Bottle Feeding - While most experts believe that breast-feeding is nutritional better for infant presents problems for working mom Malnutrition - Infants who are malnourished in their first year may suffer from marasmus wasting away of body tissues caused by severe protein-calorie deficiency leads to severe underdevelopment of child’s cognitive, physical & emotional growth

Motor Development Gross and Fine Motor Skills Skills infant learns through muscle control Gross skills utilize large muscles for larger motor activities such as moving arms or legs Fine skills involve more finely turned movements such as finger dexterity.

Reflexes of children Rooting reflex –

Eyeblink Reflex

Sucking Reflex

Moro Reflex When the baby hears a loud noise or their head falls back, they may instinctively extend arms out, arch its back and bring arms toward each other as though they are trying to grab someone.

Palmar and Plantar Grasp Reflex Palmar- Plantar-

Tonic Neck Reflex The tonic neck reflex, or fencer response, is present at birth This reflex usually disappears by 4-9 months.

Babinski Reflex Babinski's reflex occurs when the great toe flexes toward the top of the foot and the other toes fan out after the sole of the foot has been firmly stroked abnormal after the age of 2.

Sensory Development Discerning faces - 1 month old babies appear to be able to distinguish mother’s face: At 3 months, baby appears to distinguish mother:

Sight Babies are born legally blind with a vision of 20/600 – you need to be no more than 8 inches from their face By 6 months they are at 20/100 – you need to be at least a few feet away By 9 months they are at 20/60 – they can see you across the room

By age two, vision will be about 20/20 For the first couple of months, babies will be able to distinguish patterns, but tend to respond to blacks and reds By 5 or 6 months, babies begin to discern colors A word about pastels

Hearing By 1 month: By 6 months, they have developed the ability to understand and:

Touch Newborns have a well-developed sense of touch and will, over time, come to use this sense a lot Babies will begin to explore their world using tactile sensations, which is why many of the toys for infants have different textures

Smell 1-day-old infants can: 1 ½-month-old infants can distinguish between the smell of their mother and that of a stranger (which is why people tell you to leave the baby with something that has your smell on it)

Taste Newborns appear to prefer the taste of sweet and salty and dislike bitter-tasting things It has been observed that during pregnancy infants will lick the placenta wall which may help to develop a sense of taste

Depth Perception Visual cliff experiment -

Visual Cliff Experiment 3-month-old babies would have their: 6-month-old babies would have their heartbeat increase when approaching the “ledge” – would not crawl across, although some did when mother prompted them to

Depth Perception Three-dimensional vision does not develop until: Brain needs experience to develop: Crawling builds 3-D vision.