The First Two Years: Biosocial Development Slides prepared by Kate Byerwalter, Ph.D., Grand Rapids...

transcript

The First Two Years: Biosocial Development

Slides prepared by Kate Byerwalter, Ph.D., Grand Rapids Community College

The Developing Person Through Childhood and Adolescence by Kathleen Stassen Berger

Chapter 5

Seventh Edition

Berger: The Developing Person Through Childhood and Adolescence, 7th Edition, Chapter 5

Body Changes

An average newborn is 7½ lbs, 20 inches.

Infants triple their birthweight by 1 year.

By age two, they are about ½ their adult height (!) and ¼ their adult weight.

Body Changes

ALL: INES YVETTE LARAYA ERESE

Body Changes (cont.)

Percentile ranks: allow comparisons of an individual infant to group norms

A sudden drop in percentile rank might indicate a developmental problem.

Head Sparing: in cases of inadequate nutrition, the brain keeps growing

The Wonderful World of SLEEP Newborns sleep 17+ hours a day.

DAVID YOUNG-WOLFF / PHOTOEDIT, INC.

Infant Sleep (cont.)

Infants gradually adjust to the family’s sleep schedule.

80% of 1 year olds sleep “through the night”

Sleep cycles are influenced by brain maturation, diet, child-rearing practices, and birth order

Make It Real: Co-Sleeping

Some families practice “co-sleeping,” in which the family shares a bed.

Why might a family do this? Do you think it could benefit or harm an infant?

Research on Co-Sleeping CULTURE influences the decision (it is

more common in Eastern culture)

It is not harmful to an infant, under normal circumstances (e.g., if adult is not drunk)

It may increase dependence on parents

Brain Development

Brain development during infancy is fascinating and rapid.

By the age of 2, the brain is 75% its adult weight

Neural connections in the brain also develop

Brain Development (cont.)

Regional specialization: neurons in certain areas of the brain correspond to different tasks

Examples: language, vision, smell, emotional processing, recognizing faces vs. objects, etc.

The Developing Cortex

Brain Development (cont.)

Transient exuberance: rapid proliferation of new neural connections in infancy

As many as 15,000 new connections per

neuron and 100 trillion synapses by age 2!

Pruning makes the brain more efficient by eliminating underused connections.

What influences early brain development?

Brain development is influenced by maturation and experiences.

Experience-expectant brain functions require basic common experiences.

Example: No matter where an infant lives, he or she hears sounds and language.

What influences early brain development? (cont.)

Experience-dependent brain functions depend on exposure to particular events.

Example: The particular sounds and language heard (and learned) varies across infants.

Example: The development of impulse control depends on both maturation and practice.

Why are neural connections so important?

A certain level of neural connections indicate healthy brain development.

Lack of connections may result from child abuse or neglect early in life, and can have lasting consequences.

Example: Infants in orphanages

Make it Real: Activities

Make a list of toys and activities that can stimulate healthy brain development in the first two years of life. PHOTODISC

Implications for Caregivers

Is it possible to overstimulate an infant? YES!

The key is to follow the infant’s lead

Self-righting: an infant’s inborn drive to use whatever experiences available to develop the brain (wow!)

Infant Senses

All five senses function at birthVision, hearing, taste, touch, smell

Perception (the brain’s processing of the sensation) develops over time.

Infant Senses (cont.)

Hearing: is well developed at birth Infants respond to sudden noises, human

voice, phonemes of language

Vision: is the least mature sense at birthBionocular vision develops around 14 weeks“Adult” vision (20/20) by one year

Infant Senses (cont.)

Taste, touch, smell function well at birth

All: CINDY CHARLES / PHOTOEDIT, INC.

Motor Skills

Motor skills develop according to two principles:

Cephalocaudal: growth proceeds from head-to-toe (e.g., head lift before sit, stand, walk)

Proximal-distal: growth proceeds from torso outward (e.g., sucking before kicking)

Motor Skills (cont.)

Reflexes account for the first motor skills.

Survival reflexes include sucking, breathing, body temperature.

Other reflexes include the Babinski, Moro, and stepping reflexes.

Infant Reflexes

JENNY WOODCOCK; REFLECTIONS PHOTOLIBRARY / CORBIS

PETIT FORMAT / PHOTO RESEARCHERS, INC.

ASTIER / BSIP / SCIENCE SOURCE / PHOTO RESEARCHERS, INC.

Make it Real: Motor Skills

At what age do you think most infants learn to walk?

What about you?PHOTODISC

Motor Skills (cont.) Gross motor skills involve large muscle

movements.

Examples: crawling, sitting, walking

Walking typically occurs around 12 months, with great variability across infants.

Walking requires muscle strength, brain maturation, and practice.

Motor Skills (cont.)

Fine motor skills involve small muscle movements.

Examples: learning to grasp, shake, pull an object, hold a spoon, write, draw, etc.

Motor skills are influenced by genes, culture, and patterns of infant care.

Public Health Measures

Infant survival rates have increased significantly in the past century, due to better nutrition, cleaner water, and immunization.

Although not without controversy, immunization has been hailed as a major achievement (e.g., significantly reducing polio, small pox, measles).

Sudden Infant Death Syndrome

SIDS is infant death of an unknown cause.

Protective factors (although not a guarantee) include: NO cigarette smoke in house, noise and touch during sleep, breast feeding, sleeping on back

The First Two Years: Biosocial Development Slides prepared by Kate Byerwalter, Ph.D., Grand Rapids...

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