Chapter 5 Infancy - Physical Development
Body Growth • Norms are quantitative measures that provide typical values and variations in height and weight of children
Newborns initially lose weight. • After the initial weight loss, newborns begin to gain weight rapidly. • Doubling their weight in5 months and tripling it in 12 months
The head and the central nervous system begin to gain weight rapidly and very early. • Infant heads are about 2 times larger in proportion to their bodies than adult heads are to adult bodies.
Which are you able to do first? • Hold a ball or walk? • Infants grow and gain motor control starting from the head down to feet • this pattern is called cephalocaudal • With a partner, think of an example of cephalocaudal development.
Which are you able to do first? • Grab a stuffed animal or hold a pencil? • The body also progresses in growth from the center of body out to limbs • this pattern is called proximodistal • Working in pairs, identify one specific example of how the body develops according to proximodistal principles.
Growth rates vary from the norm and this is to be expected. • Growth rates also vary due to social influences and ethnicity.
Brain and Nervous System • Procedure names: PETscan & fMRI • At birth the brain is 25% of its adult size.
Brain and Nervous System • Parts established at birth: brainstem and midbrain • Functions controlled by these areas: digestion, elimination, & respiration
A lot of the development of the cortex takes place after birth • This part is responsible for: sensation, motor response, thinking
Basic brain cells are called neurons • Insulated with myelin • Glial cells provide basic building material • Also facilitate the transfer of nutrients
Proliferation – production of new nerve cells • Migration – movement from neural tubes, where created, to new locations • Differentiation – enlarging, forming synapses with other neurons, begin to function
The first 2 processes take place before birth • The third takes place after birth • Neuron differentiation requires external Stimulation
Synapses : Avenues that connect individual nerve cells with other nerve cells • The importance of surplus synaptic connections: Allows for rich variety of experiences that affect development; if damage done to synapses early in life, then other synapses will take over
Plasticity: ability of certain areas of cerebal cortex to take over and function for other areas that may be damaged or destroyed • The brain is most plastic during infancy and toddlerhood
Do you think the brain of a musician is the same as the brain of an author? • Why or why not? • What do you think influences this?
Experience-expectant stimulation • Development that won’t occur unless a particular experience occurs during its critical period. • Similar for all people • ordinary opportunity to see, touch and hear things (read a book)
Experience-dependent stimulation • Experiences vary from one individual to another and are not predetermined • a violinist’s is different from a poet’s brain
Brain lateralization: one hemisphere of brain dominates the other hemisphere in terms of a certain function • Most babies lie with head to right and suck right thumb. This indicates right-handedness (dominance).
Healthy reflexes are an indication that Neurological development is good. • Most reflexes disappear in the first 6 months. • Sucking/rooting reflexes insure a baby gets nutrients. • 3 milestones that illustrate the cephalocaudal pattern • Rooting > stepping > body rotating
Postural control – maintain upright sitting position • Locomotion – crawling and creeping • Manual control – pincer grasp
Is genetics or experience more important to motor development? • Both contribute – development occurs in order and at predictable times; identical twins master skills at same time while fraternal twins do not; children in orphanages who aren’t stimulated don’t walk until late
Newborns average 16 hours of sleep per every 24 hours • By age 3 – 5 weeks a sleep pattern develops with longer periods of sleep at night. • Sleep patterns for newborns and adults differ: • newborns have 8 hours of REM for every 16 hours of sleep – adults have 2 hours REM for every 7 hours of sleep
Stimulation of the central nervous system takes place when awake, but newborns aren’t awake very much. Stimulation also takes place during REM and therefore it is important for newborns to spend more sleep hours in REM
SIDS – Sudden Infant Death Syndrome • A child is at highest risk for SIDS from 2 – 4 months • http://www.childrensnational.org/research/OurResearch/disorders/cccr/CribDeathSIDS-Facts.aspx
Let’s watch a video about preventing SIDS • http://www.youtube.com/watch?v=AFZCmia2kyg
Things that can lower the risk of SIDS are: • Eliminate cigarette smoke exposure • Firm bedding provided • Avoid overheating • Use pacifier when sleeping
After gaining as much information from a stimulus as possible, a child loses interest. This is known as • Habituation • When once again exposed to a new stimulus, a child’s interest is rekindled, it is known as • Recovery from habituation (dishabituation)
Classical Conditioning: • http://www.schooltube.com/video/4fa236b57fe14762a238/Classical-Conditioning • Most famous – Pavlov’s dogs • Injection needle > fear • Doctor + injection needle > fear • Doctor > fear • Create an example of your own.
Operant Conditioning • http://www.schooltube.com/video/caa02d0b960d4738b8c7/Operant-Conditioning-BF-Skinner • Most famous – B.F. Skinner • Smile at parent > parental interaction + picked up • Use potty > get potty treat • Create an example with partner
Negative Reinforcement, Positive Reinforcement, and Punishment • Positive Reinforcement v. Negative Reinforcement v. Punishment.doc
What is deferred imitation? Let’s look at the words and see if we can come up with the definition. • Imitate a behavior after some period of time (several hours, days or weeks later)
Young babies are capable of both imitation and deferred imitation. Why is this so important? • Young children able to selectively imitate behaviors in order to learn important social & cultural skills of a society
When studying infant attention, researchers have focused on • Preferential behaviors • Explain the experiment that used infants’ rate of sucking to learn about their ability to distinguish different sounds. • Hard sucking produced “PA” sound; when baby habituates to “PA” and they stop sucking, when hear “BA”, begins sucking hard again to hear “BA”
At what age is infant vision nearly adult level? • 3 months • At what age is an infant’s ability to track a moving object at adult level? • 6 – 8 months • At what age is an infant’s ability to see color at adult level? • 3 months becomes adult-like • When does the ability to hear human speech sounds develop • 23 weeks prenatal
Mothers read Cat in the Hat while prenatal – then read after birth while sucking pacifier that would start the reading of Cat in the Hat or another story – babies sucked to start Cat in the Hat but didn’t suck for another story.
To allow for early intervention • 3 -4 days • Develop before birth but newborns discriminate • Yes – if tastes unpleasant early in life (like milk or formula) then more tolerant of unpleasant tastes later in life
Skin • Yes • Accelerate weight gain • Facilitate social interaction between caregiver and baby
Too hot: Reddening of skin, less activity, more sleep, extend extremities • Too cool: restless, increase oxygen consumption
Know that brain centers for pain detection are well developed prenatally; painful experiences early in life leads to lasting changes in endocrine and immune systems + behavioral sensitivity to pain later