Infants, Children, and Adolescents Eighth Edition Chapter 8 Physical Development in Early Childhood

Learning Objectives (1 of 2) 8.1 Describe changes in body size, proportions, and skeletal maturity during early childhood. 8.2 Describe brain development in early childhood. 8.3 Explain how heredity influences physical growth. 8.4 Describe the effects of emotional well-being, restful sleep, nutrition, and infectious disease on physical growth and health in early childhood. 8.5 What factors increase the risk of unintentional injuries, and how can childhood injuries be prevented?

Learning Objectives (2 of 2) 8.6 Cite major milestones of gross- and fine-motor development in early childhood. 8.7 Describe individual differences in preschoolers’ motor skills and ways to enhance motor development in early childhood.

Physical Development in Early Childhood Body growth slows: Child’s shape becomes more streamlined. Individual differences in size become more apparent. Skeletal growth continues: New epiphyses emerge. Primary teeth are replaced by permanent teeth.

Body Growth During Early Childhood Figure 8.1: Body growth during early childhood Figure 8.1 Photos of Wilson: Diahanne Lucas; Photos of Mariel: © Jim West Photography

Brain Development Between ages 2 and 6, the brain increases to 90% of its adult weight. undergoes reshaping and refining. Preschoolers improve in physical coordination. perception, attention, and memory. language. logical thinking. imagination.

Brain Development (continued) Brain plasticity ensures that child will acquire certain abilities even if some brain areas are damaged. declines as synaptic pruning occurs. Cognitive functions increasingly localize in distinct neural systems. Rapid growth occurs in prefrontal-cortical areas devoted to executive function.

Handedness Reflects greater capacity of dominant cerebral hemisphere to carry out skilled motor action. Begins as early as tenth prenatal week. Affected by prenatal events, practice, and culture. Early damage to left hemisphere may cause shift in handedness, but most left-handers have no developmental problems. Unusual lateralization may have certain advantages.

Cross-Section of the Human Brain Cerebellum: structure that aids in balance and control of body movement Reticular formation: structure in brain stem that maintains alertness and consciousness Hippocampus: inner-brain structure that plays a vital role in memory and spatial understanding Amygdala: inner-brain structure that processes novelty and emotional information Corpus callosum: large bundle of fibers connecting the two cerebral hemispheres

Cross-Section of the Human Brain Figure 8.2: Cross-section of the human brain, showing the location of the cerebellum, the reticular formation, the hippocampus, the amygdala, and the corpus callosum Figure 8.2

Influences on Physical Growth and Health Heredity and hormones Emotional well-being Sleep habits and problems Nutrition Infectious disease Childhood injuries

Low-Level Lead Exposure and Children’s Development Longitudinal studies show negative relationship between lead exposure and IQ. Since 1980, laws limiting lead content of paint and mandating lead-free gasoline have led to a sharp decline in children’s lead levels. Low-SES children are more likely to live in lead-contaminated areas and to experience risks that magnify lead-induced damage.

Relationship of Lead Exposure to 11- to 13-Year-Olds’ IQ by SES Figure 8.3: Relationship of lifetime average lead exposure to 11- to-13-year-olds’ IQ by SES Figure 8.3 (Based on Tong, McMichael, & Baghurst, 2000.)

Heredity and Hormones Children’s physical size and growth rate are related to their parents’. Genes influence growth by controlling hormone production. Pituitary gland releases two growth-inducing hormones: Growth hormone (GH) is necessary for development of almost all body tissues. Thyroid-stimulating hormone (TSH) prompts release of thyroxine, needed for brain development and for full impact of GH.

Emotional Well-Being Children’s emotional well-being profoundly affects their growth and health. High stress suppresses release of GH. Extreme emotional deprivation can lead to psychosocial dwarfism, characterized by decreased secretion of GH and melatonin. very short stature and immature skeletal age. serious adjustment problems.

Sleep Habits and Problems Sleep contributes to body growth and cognitive performance. Sleep difficulties are associated with impaired cognitive performance. Children’s poor sleep affects parents’ sleep, generating family stress. Variations by ethnicity are seen in napping, bedtime routines, and cosleeping.

Sleeping Arrangements of U.S. 3-Year-Olds by Ethnicity Figure 8.4: Sleeping arrangements of U.S. 3-year-olds by ethnicity Figure 8.4 (Based on Milan, Snow, & Belay, 2007.)

Nutrition Appetite becomes unpredictable. Most preschoolers prefer familiar foods. Social environment influences food choices: Children imitate food choices of people they admire. Repeated, unpressured exposure to new foods increases acceptance. Emotional climate at mealtimes has powerful impact. Restricting foods increases child’s desire for those foods. Children living in poverty may lack access to sufficient high-quality food.

Dietary Deficiencies in Early Childhood Most common dietary deficiencies of preschool years: Protein Essential vitamins and minerals: iron, calcium, zinc, vitamin A, vitamin C Effects of nutritionally deficient diet: Small size Attention and memory difficulties Poorer intelligence and achievement test scores Hyperactivity and aggression

Encouraging Good Nutrition Offer a varied, healthy diet. Offer predictable meals and several snacks daily. Serve small portions, and allow the child to have seconds. Offer healthy new foods repeatedly and patiently. Keep mealtimes pleasant and noncoercive. Avoid using food as a reward or restricting access to certain foods.

Infectious Disease and Malnutrition Poor diet depresses the immune system, making children susceptible to disease. Disease contributes to malnutrition, hindering physical growth and cognitive development. Widespread diarrhea in developing countries leads to 1 million childhood deaths annually: Impairment and death can be prevented with oral rehydration therapy (ORT). Zinc supplements also reduce incidence of diarrhea.

Immunization Widespread immunization has led to dramatic decline in childhood diseases in industrialized nations. About 20% of U.S. infants and toddlers and 17% of preschoolers are not fully immunized: Many low-income families lack health insurance coverage or a primary-care physician. Some parents believe discredited media reports of a link between vaccination and autism. Public education on immunization is badly needed.

Otitis Media and Development Otitis media (middle ear infection) is most common between 6 months and 3 years. Rates nearly double in children who attend child-care centers. Frequent cases can disrupt language and academic progress. Prevention: Frequent screening Prompt medical attention Infection control in child-care settings Verbally stimulating adult–child interaction Vaccines

Factors Related to Childhood Injuries Injuries occur within a complex ecological system of influences. Individual differences: Gender Temperament Family, community, and societal factors: Poverty, single parenthood, low parental education Child-care shortages, teenage parenthood Societal conditions in developing nations

International Death Rates due to Childhood Injury Figure 8.6: International death rates due to unintentional injury among 1- to 14-year-olds Figure 8.6 (Based on World Health Organization, 2008.)

Preventing Childhood Injuries Laws prevent many injuries (car safety seats, child-resistant caps, flameproof clothing). Many parents and children behave in ways that compromise safety: Safety seats: 27% of U.S. parents don’t use them; of those who do, 40% to 84% use them incorrectly. Parents overestimate children’s knowledge of safety rules, rather than monitoring and controlling access to hazards.

Reducing Unintentional Injuries Provide age-appropriate supervision and safety instruction. Know the child’s temperament. Eliminate the most serious dangers from the home. Always restrain children properly in back seat of car. Select safe playground equipment and sites. Be extra cautious around water. Practice safety around animals.

Motor Skill Development in Early Childhood Gross-motor skills: Walking, running, jumping, hopping Catching, throwing, swinging, riding Fine-motor skills: Self-help: dressing, eating Drawing: line and circle, tadpole image

Changes in Throwing During Early Childhood Figure 8.7: Changes in throwing during early childhood Figure 8.7 (Adapted figures drawn from film tracings taken in the Motor Development and Child Study Laboratory, University of Wisconsin–Madison and now available from the Motor Development Film Collection, Kinesiology Division, Bowling Green State University. © Mary Ann Roberton. Reprinted by permission of Mary Ann Roberton.)

Changes in Gross- and Fine-Motor Skills During Early Childhood Age Gross-Motor Skills Fine-Motor Skills 2–3 years Jumps, hops, throws, and catches with rigid upper body Pushes riding toy with feet; little steering Puts on and removes simple items of clothing Uses large zippers Uses spoon effectively 3–4 years Jumps and hops, flexing upper body Throws and catches with slight upper-body involvement Pedals and steers tricycle Fastens and unfastens large buttons Serves self food without help Uses scissors Draws first picture of person 4–5 years Runs more smoothly Gallops and skips Throws with increased body rotation Uses fork effectively Cuts with scissors following line Copies shapes and some letters 5–6 years Increases running speed Mature throwing, catching Rides bicycle with training wheels Uses knife Ties shoes Draws more detailed person Copies numbers and simple words

Progression of Drawing Skills Scribbles: during second year First representational forms: Around age 3: Labels already-made drawings. Age 3–4: Draws boundaries and tadpole-shaped people. More realistic drawings: preschool to school age Early printing: ages 4–6

Progression of Drawing Skills Figure 8.8: Examples of young children’s drawings Figure 8.8 (Left: From H. Gardner, 1980, Artful Scribbles: The Significance of Children’s Drawing, New York: Basic Books, p. 64. Copyright © 1980 by Howard Gardner. Reprinted by permission of Basic Books, a member of the Perseus Books, conveyed through Copyright Clearance Center. Right: From E. Winner, “Where Pelicans Kiss Seals,” Psychology Today, 20[8], August 1986, p. 35. Reprinted by permission from the collection of Ellen Winner.)

Development of Children’s Drawings of Geometric Objects Figure 8.9: Development of children’s drawings of geometric objects—a cube and a cylinder Figure 8.9 (Based on Toomela, 1999.)

Chinese Children’s Advanced Drawing Skills Several cultural factors promote advanced drawing skills in Chinese children: 4,000-year-old artistic tradition Belief that creativity must build on a foundation of artistic knowledge and techniques Instruction in painting using prescribed brush strokes Writing instruction that emphasizes details of characters In contrast, U.S. art education is more diverse and emphasizes independence and self-expression.

Development of Printing Up to age 3 Scribbles Varied pencil grips Ages 4–6 Gradual realization that writing stands for language Identification of individual letters Adult pencil grip by age 5

Variations in 3-Year-Olds’ Pencil Grip Figure 8.11: Variations in 3-year-olds’ pencil grip Figure 8.11 (Based on Greer & Lockman, 1998.)

Individual Differences in Motor Skills Body build: Taller, more muscular bodies move more quickly, acquire skills earlier. Sex: Boys are ahead in skills requiring power and force. Girls are advantaged in fine-motor skills and in skills requiring good balance and foot movement. Social pressures channel children into activities.

Enhancing Early Childhood Motor Development Motor skills are best mastered through everyday play: Formal lessons have little added impact. Preschoolers should have at least 60 minutes a day of adult-structured play, plus several hours of child-directed play. Children need appropriate play spaces and equipment. Daily routines support fine-motor development.

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