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Chapter 4:

Physical Development in Infancy

Did your mother breast-feed or not? Why? What were the views during that time about doing so? What are their memories of your sleep habits, eating habits, motor development, crying, stimulus response, and potty training? In what ways do they remember you changing the most? Enjoy this walk down memory lane with your parents and either read your text prior to your conversation or soon afterward to link your own story with the specific developmental issues covered.

Learning Goals

Learning Goal 1: Discuss physical growth and development in infancy.

A. Describe the patterns of growth.

B. Discuss height and weight in infancy.

C. Explain brain development during infancy.

D. Discuss infant sleep patterns.

E. Describe infant nutritional needs.

Learning Goal 2: Describe infants’ motor development.

A. Discuss the dynamic systems view of motor development.

B. Discuss infant reflexes.

C. Discuss how gross motor skills are developed.

D. Discuss how fine motor skills are developed.

Consider this: Latonya is a newborn baby in Ghana. During her first days of life, she has been kept apart from her mother and bottle fed. Manufacturers of infant formula provide the hospital where she was born with free or subsidized milk powder. Her mother has been persuaded to bottle feed rather than breast feed her. When her mother bottle feeds Latonya, she overdilutes the milk formula with unclean water. Latonya's feeding bottles have not been sterilized. Latonya becomes very sick. She dies before her first birthday.

Ramona was born in a Nigerian hospital with a “baby-friendly” program. In this program, babies are not separated from their mothers when they are born, and the mothers are encouraged to breast feed them. The mothers are told of the perils that bottle feeding can bring because of unsafe water and unsterilized bottles. They also are informed about the advantages of breast milk, which include its nutritious and hygienic qualities, its ability to immunize babies against common illnesses, and the role of breast feeding in reducing the mother's risk of breast and ovarian cancer. Ramona's mother is breast feeding her. At 1 year of age, Ramona is very healthy.

What roles might programs like this play in communities in the United States?

 Patterns of Growth:  Cephalocaudal Pattern: sequence in which the earliest growth always occurs from

the top downward  Also applies to gains in motor development

 Proximodistal Pattern: sequence in which growth starts in the center of the body and moves toward the extremities

 Height and Weight:  Average North American newborn is 20 inches long and 7.5 pounds  95% of full-term newborns are 18-22 inches long and weigh between 5 ½ and

10 lbs.  Newborns lose 5-7% of their body weight in the first few days of life

 They typically gain 5-6 ounces per week during the first month  Weight usually triples by their 1st birthday

 Newborns gain approximately 1 inch per month during the first year  Growth slows considerably during the 2nd year

 The Brain:  Brain continues developing past infancy  Shaken Baby Syndrome: brain swelling and hemorrhaging from child abuse trauma  Brain imaging technologies cannot typically be used with babies  EEGs show regular spurts in the brain’s electrical activity  Spurts may coincide with important changes in cognitive development

 At birth, the brain is 25% of its adult weight; at 2 years of age, it is 75% of its adult weight  The brain does not mature uniformly

Think About It:

 If your child were crying and you were becoming very frustrated, what are some things you might do so that you can calm down?

 Forebrain: portion of the brain farthest from the spinal cord; includes cerebral cortex  Cerebral Cortex: folded surface covering the forebrain

 Cerebral cortex is divided into 2 hemispheres, each with 4 lobes  Frontal lobe: voluntary movement, thinking, personality, and intentionality

 Occipital lobe: vision functions  Tempora; lobe: hearing, language processing, and memory  Parietal lobe: spatial location, attention, and motor control

 Lateralization: specialization of function in one hemisphere of the cerebral cortex or the other  Some functions are lateralized, some are not  Complex functions involve communication between both hemispheres

 Neurons brain nerve cells that communicate through electrical and chemical signals  Axons carry signals away from the cell body  Dendrites carry signals toward the cell body  Myelin sheath is a layer of fat cells that insulate axons  Helps electrical signals travel faster

 Terminal buttons release chemicals (neurotransmitters) into synapses  Neurotransmitters: A chemical that is contained at the end of the axon whose

purpose is to pass information on to another neuron  Synapses: tiny gaps between neurons

 Changes in Neurons:  Myelination: the process of encasing axons with fat cells  Begins prenatally and continues into adolescence

 Connectivity among neurons increases  New dendrites grow  Connections among dendrites increase  Synaptic connections increase

 More synaptic connections are created than will ever be used  Leads to a “pruning” of unused connections

 Changes in regions of the brain:  “Blooming and pruning” of synapses varies by brain region

 Depressed brain activity has been found in children who grow up in a deprived environment  Enriched environments promote faster brain development than deprived ones These orphans were found in an orphanage basically confined to their cribs. They did not receive any stimulation, socialization, proper bathroom training. Thankfully, they were able to rebound with therapy once they were found.

 Brain is both flexible and resilient

 After birth: sights, sounds, smells, touches, language, and eye contact help shape the brain’s neural connections  Repeated experience wires (and rewires) the brain.

What implications does this case have for kids who have been neglected? How do we properly stimulate children?

Sleep:

 Typical newborns sleep 16-17 hours per day  Infants vary in their preferred times for sleeping

 Most have moved closer to adult-like sleep patterns by 4 months of age The most common infant sleep-related problem reported by parents is nighttime waking (Hospital for Sick Children & others, 2010). Surveys indicate that 20 to 30 percent of infants have difficulty going to sleep at night and staying asleep until morning (Sadeh, 2008). A recent study found that nighttime wakings at 1 year of age predicted lower sleep efficiency at 4 years of age (Tikotzky & Shaashua, 2012). Also, a study revealed that the mother's emotional availability at bedtime was linked to fewer infant sleep problems, supporting the premise that parents' emotional availability to infants in sleep contexts

increases feelings of safety and security, and consequently better-regulated infant sleep (Teti & others, 2010). Another study found that a higher involvement of fathers in overall infant care was related to fewer infant sleep problems (Tikotzky, Sadeh, & Glickman- Gavrieli, 2010). However, infant nighttime waking problems have consistently been linked to excessive parental involvement in sleep-related interactions with their infant (Sadeh, 2008). Further research found that maternal depression during pregnancy, early introduction of solid foods, infant TV viewing, and child care attendance were related to shorter duration of infant sleep (Nevarez & others, 2010).

 Factors involved in night waking:  Daytime crying and fussing  Distress when separated from mother  Breast feeding  Co-sleeping

 Cultural variations influence infant sleeping patterns

 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  We do not know whether infants dream or not

 The practice of shared sleeping, in which a newborn shares a bed with mother, varies among cultures

 Potential benefits:  Promotes breast feeding and a quicker response to crying  Allows mother to detect potentially dangerous breathing pauses in baby

 American Academy of Pediatrics discourages shared sleeping  Increases risk of injury (rolling over baby) and SIDS

Question:

 What does your culture say about shared sleeping?

 SIDS (Sudden Infant Death Syndrome) infants stop breathing and die without apparent cause  Highest cause of infant death in U.S. annually  Highest risk is 2-4 months of age (my friend had a child at 18 and her baby died of

SIDS at 4 months)  Risk decreases when infant sleeps on its back and when a pacifier is used

 Other risk factors associated with SIDS:  Siblings who died from SIDS  Sleep apnea or low birth weight  Infants passively exposed to cigarette smoke  Being from lower SES or being African American or Eskimo  Infants placed in soft bedding  Infants with abnormal brain stem functioning involving serotonin

What can parents and other caregivers do to lower the risk of SIDS?

• Place babies to sleep on their backs unless advised otherwise by a physician. • Place the baby on a firm mattress, such as in a safety-approved crib or other firm surface. • Remove all fluffy and loose bedding, such as fluffy blankets or other coverings, pillows,

quilts, and stuffed toys, from the baby’s sleep area. • Get good prenatal care, including proper nutrition, avoid maternal smoking or drug/alcohol

use, and go for frequent medical checkups beginning early in pregnancy. • Take babies for regular checkups and routine immunizations. • See this link to read some stories about people who have lost an infant to SIDS:

http://sids-network.org/stories.htm

Nutrition:

 Experts recommend that infants consume 50 calories per day for each pound they weigh

 U.S. parents typically do not feed infants enough fruits and vegetables  By 15 months, French fries are the most common vegetable eaten. French fries,

people!

 Increasing rates of overweight and obese infants  Other factors:  Mother’s weight gain during pregnancy and pre-pregnancy weight  Breast feeding vs. bottle feeding

 American Academy of Pediatrics strongly endorses breast feeding throughout the first year

 Benefits for baby can include:  Fewer gastrointestinal and lower respiratory tract infections  Potentially decreased risk of asthma  Less likely to become overweight or obese  Less incidence of diabetes  Less likely to experience SIDS

 Benefits for mother can include:  Lower incidence of breast and ovarian cancer  Lower incidence of Type 2 diabetes

 Breast feeding does not:  Help mother return to pre-pregnancy weight  Guard against osteoporosis  Decrease likelihood of experiencing post-partum depression

 Women less likely to breast feed:  Mothers who work full-time outside of the home  Mothers under age 25  Mothers without a high school education  African-American mothers

 Mothers in low-income circumstances

 Mother should not breast feed if:  She has AIDS or other infectious diseases that can be transmitted through milk  She has active tuberculosis  She is taking a drug that may not be safe for the infant

 No psychological differences have been found between breast-fed and bottle-fed infants

 Most breast- vs. bottle-feeding studies are correlational and do not imply causation

Question

 What are some factors that might impact the foods parents feed their babies?

 Malnutrition in Infancy:  Early weaning and inadequate sources of nutrients can cause malnutrition  Marasmus: a severe protein-calorie deficiency  Results in a wasting away of body tissues

 Kwashiorkor: a severe protein deficiency that causes the abdomen and feet to swell with water  Causes the vital organs to collect nutrients, depriving other parts of the body

 Severe and lengthy malnutrition is detrimental to physical, cognitive, and social development

Motor Development:

 Reflexes: built-in reactions to stimuli; generally carry survival mechanisms  Rooting Reflex: when the infant’s cheek is stroked, the infant will turn its head to the

side that was touched  Moro Reflex: automatic arching of back and wrapping of arms to center of body

when startled  Grasping Reflex: infant’s hands close around anything that touches the palms

 Some reflexes continue throughout life; others disappear several months after birth  Gross Motor Skills: skills that involve large-muscle activities

 Walking, grabbing for objects  Gross motor skills require postural control

 Posture is a dynamic process linked with sensory information in the skin, joints, and muscles

 Infants can produce stepping movements needed for walking from a very early age

 They lack the ability to stabilize balance on one leg at a time  Infants learn what kinds of places and surfaces are safe for locomotion

 Development in the 2nd Year:  Toddlers become more skilled and mobile  Motor activity is vital to the child’s development of competence and independence  By 18-24 months, toddlers can:  Walk quickly or run stiffly  Balance on their feet in a squat position  Walk backward  Stand and kick a ball without falling  Jump in place

 Cultural Variations: mothers in developing countries tend to stimulate their infants’ motor skills more than mothers in more modern countries ( I once had a student who’s baby’s father was from Jamaica and would always stretch the babies limbs and massage them, under the belief that it would stimulate the babies motor development)  Infants can reach motor milestones slightly earlier if provided with physical guidance

or given opportunities for exercise  Even when activity is restricted, many infants still reach milestones at a normal age

 Fine Motor Skills: involve finely tuned movements

 Reaching and grasping is a significant milestone for infants  Palmer grasp: grasping with the whole hand  Pincer grip: grasping with the thumb and forefinger

Sight:  Experienced infants look at objects longer, reach for them more, and are more likely to

mouth the objects

 Habituation: decreased responsiveness to a stimulus after repeated presentations

 Dishabituation: recovery of a habituated response after a change in stimulation

Video clip of habituation http://www.youtube.com/watch?v=UiB2ZX1phmc

 Newborn’s vision is about 20/600 (an object 20 feet away appears as if it were 600 feet away)

 By the age of 6 months, vision is 20/100 or better  Vision approximates that of an adult by the infant’s first birthday

 Infants show an interest in human faces soon after birth  The way they gather information about the visual world changes rapidly with age

Here are some good web-resources for you to check out for more information:

American SIDS Institute

http://www.sids.org/

Circumcision Information and Resource Pages (CIRP)

http://www.cirp.org/

Infant Senses

http://life.familyeducation.com/baby/sensory-integration/50444.html

La Leche League International (Breastfeeding)

http://www.lalecheleague.org/

Malnutrition

http://emedicine.medscape.com/article/985140-overview

National Center on Shaken Baby Syndrome

http://www.dontshake.org/

National SIDS/Infant Death Resource Center

http://www.sidscenter.org/

Zero to Three: National Center for Infants, Toddlers, and Families

http://www.zerotothree.org/

Archive for the Developmental Psychology Category

http://www.psychotube.net/category/developmental-psychology/