1. PSYC 2314 Lifespan Development
Chapter 5
The First Two Years:
Biosocial Development

2. Physical Growth and Health
The average North American newborn measures about 20 inches and weighs about 7 lbs.
By age 1, body weight has tripled to an average 22 lbs; body length has increased to almost 30 inches.
Growth slows during the second year. By age 2, body weight averages 30 lbs, nearly 1/5 of adult weight; body length ranges from inches or ½ of adult height.
Newborn loses between 5 and 10 percent of his or her body weight during the first days of life.
Before 8 months, most of the weight gain is fat; afterward, weight gain derives more from bone, muscle, and organ growth.

3. SIDS
Caused by an unsteady breathing reflex, usually between 2-4 months.
Preventive measures:
Removing soft bedding
Eliminating second-hand smoke
Prolonging breast feeding
Laying babies down to sleep on their backs, not stomachs

4. Survival Rates
Survival in the early years of life has increased from a century ago, primarily because of immunization. Among the diseases that have either been completely eradicated, or nearly so, are smallpox, polio, whooping cough, diphtheria, and measles.

5. Brain Growth and Development
Transient exuberance—the phenomenal increase in neural connections over the first 2 years.
Neurons: axon, dendrites, synapses, myelin sheaths

6. Brain Growth and Development
As the nervous system matures, the axons become coated with myelin, allowing children to gain increasing control over their motor functions and sensory abilities, which facilitates their intellectual functioning.
The myelination process proceeds most rapidly from birth to age 4 (but continues through adolescence).

7. Brain Growth and Development
The frontal cortex, which assist in self-control and self-regulation, is immature in the newborn. As frontal neurons become myelinated and interconnected during the first year, babies become better able to regulate their reflexes and sleep-wake patterns. Cognitive abilities requiring deliberation and emotional self-control also emerge.

8. Brain Maturation
Caressing a newborn, talking to a preverbal infant, and showing affection toward a small person too immature to love in return may be essential first steps toward developing that person’s full human potential.
Loving and stimulating experiences should occur throughout life. The brain retains some plasticity—that is, some capacity for developing new pathways—as long as experience continues.

9. Motor Skills
Developmental biodynamics: the study of the maturation of movement skills.
Reflexes: the newborn’s first motor abilities
Breathing
Sucking
Rooting
Other reflexes include crying and shivering, tucking in the legs close to the body.

10. Motor Skills
Gross motor skills: physical skills involving large body movements such as waving the arms, walking, and jumping.
Fine motor skills: skills that involve small body movements (usually of the hands and fingers).
Fine motor skills are more difficult to master than gross motor skills bcs they require the precise coordination of complex muscle groups.

11. Motor Skills
Between 8-10 months, most infants are crawling on “all fours.”
Average child can walk with assistance at 9 months, stand alone momentarily at 10 months, and walk well unassisted at 12 months.
By 6 months, most babies can reach, grab, and hold onto objects.
Babies who can walk are referred to as toddlers.

12. Motor Skills
Norms reflect the average age at which certain skills are acquired. Norms vary from place to place and group to group.
Variation in norms can be attributed primarily to inherited factors, such as activity level, rate of physical maturation, and body type. Patterns of infant care may also be influential.
The age at which a particular baby first displays a particular skill depends on the interaction between inherited and environmental factors. Each infant has a genetic timetable for maturation, which can be faster or slower than that of other infants from other ethnic groups, from the same ethnic group, and even from the same family. Each infant also has a family and a culture that provide varying amounts of encouragement, nutrition, and opportunity to practice these skills.

13. Sensory and Perceptual Capacities
Sensation: detection of a stimulus
Perception: making sense of the stimulus
Vision: least developed of the senses
Hearing: Acute at birth. Can distinguish their mother’s voice from the voices of other women.
Newborns focus most readily on objects between 4-30 inches away. By 12 months visual acuity reaches 20/20.
Binocular vision develops about 14 weeks, which is required for depth and motion perception. (see the edges of the bed).
Color vision probably absent at birth. One-month-old infants can distinguish among red, green, and white, but their ability to detect other colors is limited. By 3 to 4 months, infants can distinguish many more colors and can also differentiate them.

14. Sensory and Perceptual Capacities
About 1 in every 1,000 infants is profoundly deaf.
A common cause of temporary hearing loss during infancy is middle ear infection, also known as otitis media.

15. Sensory and Perceptual Capacities
When this condition becomes chronic, the inner ear fills with fluid, and hearing may be impaired for weeks or months.
Chronic otitis media may slow learning ability, the ability to make friends, the ability to deflect aggression, and social problems solving.

16. Sensory and Perceptual Capacities
Treatments for otitis media include antibiotics and the placement of a tube to drain fluid from the inner ear.

17. Sensory and Perceptual Capacities
At birth, infants can discriminate all the basic tastes except salty.
Sense of smell is even more acute.
Sense of touch also develops rapidly.
Sense of motion is strong at birth.
By 6 months, infants can distinguish objects on the basis of their temperature, size, hardness, and texture.

18. Nutrition Breast milk is the ideal food for most babies.
Sterile and body temperature
Contains more essential vitamins and iron
More digestible
Provides the infant with immunity to any disease the mother has already had or been inoculated against
Decreases the frequency of almost every other common infant ailment
By 4-6 months, cereals and fruits should be added to the ideal diet.

19. Nutrition
Protein-calorie malnutrition: when a child does not consume sufficient nourishment
Marasmus: a condition in which growth stops, body tissues waste away, and the infant eventually dies.
Kwashiorkor: a condition caused by a deficiency of protein in which the child’s face, legs, and abdomen swell with water.
Protein-calorie malnutrition: most serious nourishment problem.
Marasmus occurs in infancy; kwashiorkor in toddlers.
Kwashiorkor: In children with this condition, the essential organs claim whatever nutrients are available, so other parts of the body become degraded. This includes the children’s hair, which usually becomes thin, brittle, and colorless. It is usually not fatal in itself, but it makes the child vulnerable to death from almost any other disease, including measles, diarrhea, and even the flu.

20. Nutrition
Primary cause of malnutrition in developing countries is early cessation of breastfeeding and the substitution of infant formulas that are often contaminated or improperly prepared.
Undernutrition is caused by a complex interaction of factors, with political and familial problems being prime underlying factors.
Socioeconomic policies in less developed nations do not reflect the importance of infant nutrition; political conflicts such as civil war make the problem worse; and parents may not even realize that their somewhat thin offspring are undernourished.

21. Nutrition
Long-lasting malnutrition in infancy can cause intellectual as well as physical deficits.
The consequences of undernutrition in infancy are more variable, depending on its duration and on the intellectual stimulation of the environment after infancy.

22. Nutrition Preventing undernutrition:
Provide supplements, nearby and nourishing, for all children
Improve maternal education so that every mother will participate