PHYSICAL DEVELOPMENT in EARLY CHILDHOOD Chapter 8 PowerPoint presentation produced by: Dr. Karen Hoblit – Associate Professor of Psychology, Victoria College This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including any transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or in part, of any of the images; any rental, lease, or lending of the program Copyright © Allyn & Bacon 2002

I. BODY GROWTH Changes in Body Size and Proportions On the average, 2 to 3 inches in height and about 5 pounds in weight are added each year. The child gradually becomes thinner; girls retain somewhat more body fat; boys slightly more muscular. Posture and balance improve, resulting in gains in motor coordination. Individual differences in body size are even more apparent during early childhood than in infancy and toddlerhood. 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.

Skeletal Growth By the end of the preschool years, children start to lose their primary teeth. Childhood tooth decay remains high, especially among low-SES youngsters in the United States and Canada

Asynchronies in Physical Growth 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, 3. Rapid growth once more during adolescence. Exceptions: the development of the reproductive lymph systems. During the first few years, the brain grows faster than any other part of the body.

Asynchronies in Physical Growth cont. Insert fig. 8.3 Growth of 3 different organ systems….. Underneath the heading in the slide above.

II. BRAIN DEVELOPMENT Synaptic Growth and Pruning Myelinization – process in which neural fibers are coated – this improves the efficiency of message transfer Many cortical regions have overproduced synapses Synaptic Growth and Pruning Neurons – nerve cells that store and transmit information Synapse – gaps between neurons – across these gaps – chemical messages are sent

Brain Development continued Overabundance of synaptic connections – plasticity of brain – many areas of brain not committed to specific function Synaptic pruning – neurons infrequently stimulated lose connective fibers and number of synapses is reduced Plasticity is reduced by 8 to 10 years old

Regions of the Cerebral Cortex

Lateralization The two hemispheres of the cortex develop at different rates. The left hemisphere shows dramatic activity between 3 and 6 years and then levels off. Activity in the right hemisphere increases slowly throughout early and middle childhood, showing a slight spurt between ages 8 and 10. Development of the two hemispheres suggest that they are continuing to lateralize (specialize in functions).

Handedness Hand preference is evident in 10 percent of 1-year-olds. By age 5, 90 percent of children clearly prefer one hand over the other. The dominant cerebral hemisphere is the hemisphere responsible for skilled motor action. In right handed individuals the left hemisphere is dominant. In left-handed individuals, motor and language skills are often shared between the hemispheres. The brains of left-handers tend to be less strongly lateralized than those of right-handers. Many left-handers are ambidextrous.

Handedness cont. One genetic theory proposes that most children inherit a gene that biases them for right-handedness and left-hemisphere localization of language. Genetic right-hand bias theory acknowledges that experience can profoundly affect handedness.

Other Advances in Brain Development The cerebellum is located at the rear and base of the brain - - aids in balance and control of body movement. The fibers linking the cerebellum to the cerebral cortex do not complete myelinization until about age 4. The reticular formation maintains alertness and consciousness; it myelinates throughout early childhood and continues growth to adolescence. The corpus callosum is the large bundle of fibers that connects the left and right hemispheres.

Linking Structures of the Brain

III. FACTORS AFFECTING GROWTH AND HEALTH Heredity and Hormones Children’s physical size and rate of growth are related to that of their parents. The pituitary gland is a gland located near the base of the brain that releases hormones affecting physical growth. Growth hormone (GH) affects the development of almost all body tissues, Short children with GH deficiency can be treated with injections of GH. Thyroid stimulating hormone (TSH) stimulates the thyroid gland to release thyroxine, which is necessary for normal development of the nerve cells of the brain and body growth.

Emotional Well-Being Preschoolers with very stressful home lives suffer more respiratory and intestinal illnesses, as well as unintentional injuries. 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 immature skeletal age decreased GH secretion. serious adjustment problems

Sleep Habits and Problems Sleep contributes to body growth, since GH is released during sleeping hours. Nightmares are common from time to time. Persistent sleep problems may be a sign of illness. Family stress can also prompt childhood sleep disturbances.

Helping Young Children Sleep Regular bed time Early enough for 10-11 hours of sleep Special pajamas

Nutrition in Early Childhood Appetite becomes unpredictable Like familiar foods Need high-quality diet Social environment influences food choices Repeated exposure to foods Emotional climate, parental pressure Poverty

Nutrition cont. Insufficient amounts of iron, calcium, vitamin C, and vitamin A are the most common diet deficiencies of the preschool years. By age 7, low-SES children in the United States are, on the average, about 1 inch shorter than their middle-class counterparts.

Infectious Disease and Malnutrition In well-nourished children, ordinary childhood illnesses have NO effect on physical growth. In developing nations, many children do not receive a program of immunizations. Disease is a major cause of malnutrition (illness reduces appetite), and, through it, affects physical growth.

Infectious Disease cont. Immunization Overall 24 percent of American preschoolers lack essential immunizations, a rate that rises to 38 percent for poverty stricken children. In contrast, fewer than 7 to 10 percent of preschoolers lack immunizations in other countries (e.g., Canada, Denmark). In 1994, all medically uninsured American children were guaranteed free immunizations, a program that has led to steady improvement in early childhood immunization rates. Misconceptions about vaccinations also contribute to inadequate immunization rates.

Childhood Injuries Most common injuries during early childhood: auto accidents, drownings, and burns Motor vehicle collisions are the leading cause of death among children over 1 year of age.

Factors Related to Childhood Injuries Individual Differences Gender Temperament Poverty, low parental education More children in the home Societal conditions International differences

Childhood Deaths From Injury Around the World

Childhood Injuries cont. Preventing Childhood Injuries cont. Childhood injuries can be reduced through legislation, improvement of the physical environment, public education. Modeling and reinforcement - apply to programs to improve the safety habits of children and adults. Attention must also be paid to family conditions that can prevent childhood injury.

Motor Skill Development in Early Childhood Gross Motor Skills - Control over actions that help infants get around in the environment Walking, running smoother Catching, throwing, swinging, riding Fine Motor Skills – smaller movements Self-help: dressing, eating Drawing

Fine Motor Development continued Shoe tying, mastered around age 6, requires a longer (1) attention span, (2) memory for an intricate series of hand movements, and the (3) dexterity to perform them.

Fine Motor cont. Progression of Drawing Skills Scribbles: during 2nd year First Representational 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. More Realistic Drawings—More conventional figures, in which the body is differentiated from the arms and legs, appear by age 6.

Fine Motor Development cont. Early Printing 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. Often the first word printed is the child’s name. In addition to gains in fine motor control, advances in perception contribute to the ability to form letters and words.

Individual Differences in Motor Skills Body Build Taller, longer limbed better at running and jumping Sex Boys: better at power and force Girls: fine motor skills, balance, foot movement

Enhancing Early Childhood Motor Development Mastered through everyday play Formal lessons have little impact Daily routines support fine motor development Provide appropriate play space and equipment Promote fun and positive attitude