PHYSICAL DEVELOPMENT in EARLY CHILDHOOD I. BODY ...

PHYSICAL DEVELOPMENT in EARLY CHILDHOOD
I. BODY GROWRTH
A. Changes in Body Size and Proportions
1. On the average, 2 to 3 inches in height and about 5 pounds in weight are added each year.
2. The child gradually becomes thinner; girls retain somewhat more body fat, whereas boys
are slightly more muscular.
3. Posture and balance improve, resulting in gains in motor coordination.
4. Individual differences in body size are even more apparent during early childhood than in
infancy.
5. To determine if a child's atypical stature is a sign of a growth or health problem, the
child's ethnic heritage must be considered.
B. Skeletal Growth s in which cartilage
1. Between ages 2 and 6, approximately 45 epiphyses, or new growth center hardens into
bone, emerge in various parts of the skeleton.
2. X-rays permit doctors to estimate children's skeletal age, the best available measure of
progress toward physical maturity.
3. By the end of the preschool years, children start to lose their primary teeth.
4. Childhood tooth decay remains high, especially among low-SES youngsters in the United
States.
C. Asynchronies in Physical Growth
1. Physical growth is an asynchronous process: different body systems have their own
unique, carefully timed patterns of maturation.
2. The general growth curve is a curve that represents overall changes in body size-rapid
growth during infancy, slower gains in early and middle childhood, and rapid growth once more
during adolescence.
3. Exceptions to this trend are found in the development of the reproductive and lymph
systems.
II. BRAIN DEVELOPMENT
A. Synaptic Growth and Pruning
1.Brain metabolism reaches a peak around 4 years of age. By this time, many cortical
regions have overproduced synapses, which results in a high energy need.
2. The overabundance of synaptic connections is believed to play a role in the plasticity of
the young brain.
3. Synaptic pruning occurs as neurons that are infrequently stimulated lose their connective
fibers and the number of synapses is reduced. This process is adaptive.
4. A surprising feature of brain development is that rapid bursts of synaptic growth are
accompanied by high rates of cell death in order to make room for the connective structures of
active neurons.
5. Plasticity is reduced by ages 8 to 10, and energy consumption of most cortical regions
declines to near-adult levels.
B. Lateralization
1.The two hemispheres of the cortex develop at different rates.
2. The left hemisphere shows dramatic activity between 3 and 6 years and then levels off.

3. Activity in the right hemisphere increases slowly throughout early and middle childhood,
showing a slight spurt between ages 8 and 10.
4. Differences in rate of development of the two hemispheres suggest that they are
continuing to lateralize .
C. Handedness
1.By age 2, hand preference is fairly stable, and it strengthens during early and middle
childhood.
2. The dominant cerebral hemisphere is the hemisphere responsible for skated motor action.
The left hemisphere is dominant in right-handed individuals. In left-handed individuals, motor and
language skills are often shared between the hemispheres.
3. The brains of left-handers tend to be less strongly lateralized than those of right-handers.
Many left-handers are ambidextrous.
4. New evidence indicates that the way most fetuses lie in the uterus-turned toward the leftmay
promote greater postural control by the right side of the body.
5. Left and mixed-handed children are more likely than their right-handed age mates to
develop outstanding verbal and mathematical talents.
D. Other Advances in Brain Development
1. The cerebellum is located at the rear and base of the brain and aids in balance and control
of body movement.
2. The fibers linking the cerebellum to the cerebral cortex do not complete myelinization
until about age 4.
3. The reticular formation maintains alertness and consciousness; it myelinates throughout
early childhood and continues growth into adolescence.
4. The corpus callosum is the large bundle of fibers that connects the left and right
hemispheres. Myelinization does not begin until the end of the first year of life, but is fairly
advanced by age 4 to 5.
III. FACTORS AFFECTING GROWTH AND HEALTH
A. Heredity and Hormones
1. Children's physical size and rate of growth are related to that of their parents.
2. The pituitary gland is a gland located near the base of the brain that releases hormones
affecting physical growth. a. Growth hormone affects the development of almost all body tissues,
except the central nervous system and the genitals. Short children with GH deficiency can be
treated with injections of genetically engineered GH. b. Thyroid stimulating hormone stimulates
the thyroid gland to release thyroxine, which is necessary for normal brain development and body
growth.
B. Emotional Well-Being
1. Preschoolers with very stressful home lives suffer more respiratory and intestinal
illnesses, as well as unintentional injuries.
2. Deprivation dwarfism is a growth disorder observed between 2 and 15 years of age that is
caused by emotional deprivation. It is characterized by very short stature, weight that is usually
appropriate for height, immature skeletal age, and decreased GH secretion.
C. Sleep Habits and Problems
1. Sleep contributes to body growth, since GH is released during sleeping hours.
2. Total sleep declines from 12 to 13 hours at ages 2 and 3 to 10 to 11 hours at ages 4 to 6.

3. Bedtime rituals, such as using the toilet, listening to a story, and kissing before turning
off the light, help Western preschoolers adjust to being left by themselves in a darkened room.
4. Almost all children begin to have a few nightmares between ages 3 to 6.
5. About 15% of preschoolers experience difficulty falling and staying asleep. Family stress
can also prompt childhood sleep disturbances.
D. Nutrition
1. Preschoolers' appetites decrease because growth has slowed.
2. in addition, they become picky eaters. This is adaptive as young children are still learning
which items are safe to eat and which are not.
3. Because caloric intake is reduced, preschoolers need a high-quality diet.
4. The social environment and emotional climate at mealtimes have a powerful impact on
children's eating habits.
5. Insufficient amounts of iron, calcium, vitamin C, and vitamin A are the most common
diet deficiencies of the preschool years.
6. By age 71 low-SES children in the United States are, on the average, about 1 inch shorter
than their middle-class counterparts.
E. Infectious Disease
1. Infectious Disease and Malnutrition: a. In well-nourished children, ordinary childhood
illnesses have no effect on physical growth. b. In developing nations, many children do not receive
a program of immunizations. c. Disease is a major cause of malnutrition, and, through it, affects
physical growth. d. Most growth retardation and deaths due to diarrhea in developing countries can
be prevented with oral rehydration therapy , in which sick children are given a glucose, salt, and
water solution that replaces lost body fluids.
2. Immunization: a. Although the majority of preschoolers in the United States are
immunized, some do not receive full protection until 5 or 6 years of age, when it is required for
school entry. b. Immunization rates in the U.S. have improved, but are still behind those of other
Western nations.
3. Day Care and Infectious Disease: a. Research in Europe and the U.S. indicates that
childhood illness rises with day care attendance. b. By age 3, over 70% of children in day care have
at least one bout of otitis media, or middle ear infection. c. Research indicates that frequent otitis
media predicts delayed language progress, social isolation in early childhood, and poorer academic
performance after school entry.
F. Childhood Injuries
1. Auto accidents, drownings, and burns are the most common injuries during early
childhood.
2. Motor vehicle collisions are the leading cause of death among children over I year of age.
3. Factors Related to Childhood Injuries: a. As with other aspects of development, injuries
take place within a complex ecological 5ystem. b. Because of their higher activity level and greater
willingness to take risks during play, boys are more likely to be injury victims than girls. c.
Irritability, inattentiveness, and negative mood are also related to childhood injuries. d. Poverty and
low parental education are strongly associated with injury deaths. e. Among Western industrialized
nations, the U.S. ranks among the highest in childhood injury mortality.
4. Preventing Childhood Injuries: a. Childhood injuries can be reduced through legislation,
improvement of the physical environment, and public education. b. The principles of applied
behavior analysis can be applied to many programs to improve the safety habits of children and
adults.

IV. MOTOR DEVELOPMENT
A. Gross Motor Development
1. As children's bodies become more streamlined and less top-heavy, their center of gravity
shifts downward toward the trunk and, as a result, their balance improves.
2. By age 2, the preschooler's gait becomes smooth and rhythmic, leading to running,
jumping, hopping, galloping, and skipping.
3. As children become steadier on their feet, their arms and torsos are freed to experiment
with new skills-throwing and catching balls, steering tricycles, and swinging on horizontal bars and
rings.
4. Five-year-olds run about twice as quickly as they did at age 2. Around age 4, gallops and
one-step skips appear, and around age 6, children can skip in a well-coordinated manner.
5. The first jumps appear around age 2. During the middle of the third year, the first twofoot
takeoffs and landings can be seen. Between ages 2 and 3, children can hop a few times in
succession, and 5- and 6-year-olds can hop skillfully.
6. At ages 2 and 3, catching and throwing are awkward and stiff. Gradually, children use
their shoulders, torso, trunk, and legs to support throwing and catching; consequently, the ball
travels faster and further.
B. Fine Motor Development
1. Self-Help Skills: a. During early childhood, children gradually become self-sufficient at
dressing and feeding. b. Shoe tying, mastered around age 6, requires a longer attention span,
memory for an intricate series of hand movements, and the dexterity to perform them.
2. Drawing and Writing: a. As the young child's ability to mentally represent the world
expands, marks on the page take on definite meaning. b. From Scribbles to Pictures: 1) Scribbles-
Western children begin to draw during the 2nd year. At first, action, rather than the scribble itself,
contains the intended message. 2) First Representational Shapes and Forms-By age 3, scribbles
start to become pictures. Use of lines to represent object boundaries permits children to draw their
first pictures of a person by age 3 or 4. 3) More Realistic Drawing5-More conventional figures, in
which the body is differentiated from the arms and legs, appear by age 6. However, drawings at this
age still contain perceptual distortions, such as a missing third dimension. c. Cultural Variations in
Development of Drawing 1) Children's drawings reflect the interest in art demonstrated by other
members of their culture. Children in cultures with little interest in art produce simpler forms. 2)
Schooling provides opportunities to draw and write, see pictures, and grasp the notion that artistic
forms have meanings shared by others. d. Early Printing: 1) As young children experiment with
lines and shapes, notice print in picture books, and observe people writing, they try to print letters
and, later on, words. 2) Often the first word printed is the child's name.
C. Individual Differences in Motor Skills
1. Body build influences gross motor abilities.
2. African-American children tend to have longer limbs, so they have better leverage in
running and jumping than do Caucasian children.
3. Boys are slightly ahead of girls in skills that emphasize force and power.
4. Girls have a slight edge in fine motor skills and in certain gross motor skills that require a
combination of good balance and foot movement, such as hopping and skipping.
5. Social pressure for boys to be active and physically skilled and for girls to play quietly at
fine motor activities may exaggerate small, genetically based differences.
D. Enhancing Early Childhood Motor Development

1 Except for throwing, there is no evidence that preschoolers exposed to formal lessons are
ahead in motor development.
2. Preschools, day care centers, and playgrounds need to accommodate a wide range of
physical abilities by offering a variety of pieces of equipment that differ in size or that can be
adjusted to fit the needs of individual children.
3. Criticism of a child's motor performance, pushing specific motor skills, and promoting a
competitive attitude may undermine young children's motor progress.
V. PERCEPTUAL DEVELOPMENT
A. Brain maturation contributes to better integration between the visual and motor systems.
B. Differentiation theory helps to explain how preschoolers learn to discriminate different letters of
the alphabet.
C. Research reveals that the ability to tune into mirror images, as well as to scan a printed line
carefully from left to right, depends in part on experience with reading materials.