PSYC 2314Lifespan Development

Chapter 5

The First Two Years:

Biosocial Development

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 32-36 inches or ½ of adult height.

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

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.

Brain Growth and Development

• Transient exuberance—the phenomenal increase in neural connections over the first 2 years.– Neurons: axon, dendrites, synapses, myelin

sheaths

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).

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.

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.

Motor Skills

• Developmental biodynamics: the study of the maturation of movement skills.

• Reflexes: the newborn’s first motor abilities– Breathing– Sucking– Rooting

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).

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.

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.

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.

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.

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.

Sensory and Perceptual Capacities

• Treatments for otitis media include antibiotics and the placement of a tube to drain fluid from the inner ear.

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.

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.

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.

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.

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.

Nutrition

• Preventing undernutrition:– Provide supplements, nearby and nourishing,

for all children– Improve maternal education so that every

mother will participate