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Chapter 5 PHYSICAL DEVELOPMENT IN INFANCY 2013 The McGraw-Hill Companies, Inc. All rights reserved.

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Cephalocaudal: The sequence in which the earliest growth always occurs at the topthe headwith physical growth and feature differentiation gradually working from top to bottom Proximodistal: Growth starts at center of body and moves toward extremities PATTERNS OF GROWTH

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.1 - CHANGES IN PROPORTIONS OF THE HUMAN BODY DURING GROWTH

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Average North American newborn is 20 inches and 7 pounds Weight doubles at about 5 months; triples by first birthday Height increase at least 50% in first year Average 2-year-old 26 to 32 pounds and 32 to 35 inches tall Growth rate considerably slower in second year Growth appears continuous but actually occurs in spurts HEIGHT AND WEIGHT

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2013 The McGraw-Hill Companies, Inc. All rights reserved. The brain is the command center of organism Extensive growth in utero and infancy Brain of neonate weighs less than one pound By first birthday, the brain triples in weight, reaching nearly 70% of adult weight EEG shows brain activity spurt from 1 to 2 years of age BRAIN DEVELOPMENT

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Forebrain: The region of the brain that is farthest from the spinal cord and includes the cerebral cortex and several structures beneath it Cerebral cortex: Tissue that covers the forebrain like a wrinkled cap and includes two halves, or hemispheres Lateralization: Specialization of function in one hemisphere of the cerebral cortex or the other MAPPING THE BRAIN

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.3 - THE HUMAN BRAINS HEMISPHERES

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2013 The McGraw-Hill Companies, Inc. All rights reserved. WHAT ARE NEURONS? Basic unit of nervous system Receive and transmit messages Neurons vary according to function and location, but all contain Cell Body Dendrites Axon Neurotransmitters

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.5 - THE NEURON

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2013 The McGraw-Hill Companies, Inc. All rights reserved. HOW DO NEURONS DEVELOP? As child matures Axons grow in length Dendrites and axon terminals proliferate Connection networks become more complex Myelin Makes messages more efficient Myelination occurs with maturation Inhibition of myelination results in disease Multiple sclerosis

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Blooming and pruning Synaptic overproduction peaks about 4 months after birth Prefrontal cortex overproduction peaks about 3 year of age Adult density achieved in adolescence Heredity and environment affect timing BRAIN DEVELOPMENT

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.6 - THE DEVELOPMENT OF DENDRITIC SPREADING

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.7 - SYNAPTIC DENSITY IN THE HUMAN BRAIN FROM INFANCY TO ADULTHOOD

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2013 The McGraw-Hill Companies, Inc. All rights reserved. The brain demonstrates both flexibility and resilience Neuroscientists believe that what wires the brain is repeated experience Neuroconstructivist view: Biological processes and environmental conditions influence the brains development The brain has plasticity and is context dependent Brain development is closely linked with cognitive development EARLY EXPERIENCE AND THE BRAIN

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Infants 0 to 2 years of age slept an average of 12.8 hours a day With a range of 9.7 to 15.9 hours The most common infant sleep-related problem reported by parents is nighttime waking Infant nighttime waking problems have consistently been linked to excessive parental involvement in sleep-related interactions with their infant SLEEP

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2013 The McGraw-Hill Companies, Inc. All rights reserved. The eyes flutter beneath closed lids In non-REM sleep, this type of eye movement does not occur and sleep is quieter REM (RAPID EYE MOVEMENT) SLEEP

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.10 - DEVELOPMENTAL CHANGES IN REM AND NON-REM SLEEP

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Culture and Sleeping Arrangements Sharing bed common in many cultures Crib/separate room common in U.S. American Academy of Pediatrics discourages co- sleeping because of stress and SIDS risk SHARED SLEEPING

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Infant stops breathing, usually during night, and dies without apparent cause Highest cause of infant death in U.S. Highest risk is 2 to 4 months of age Prone position reduces risk Less common in bedroom with fan and infant who sleeps with pacifier SUDDEN INFANT DEATH SYNDROME (SIDS)

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Healthy infants need Loving, supportive feeding environment 50 calories per day per pound of weight Breast milk (natures food) Gradual increase of chew-and-swallow More fruits and vegetables, less junk food Demand feeding becoming more popular Poor dietary patterns can cause overweight NUTRITION

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Breast milk Fewer gastrointestinal infections Lower respiratory tract infections Reduces effects of asthma in first 3 months Reduce risk of skin inflammation May lessen likelihood of obesity Lowers risk of childhood and adult diabetes Less risk of experiencing SIDS Claims of no link to allergy prevention Claims of no links to childrens cognitive development and cardiovascular system BREAST VERSUS BOTTLE FEEDING

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2013 The McGraw-Hill Companies, Inc. All rights reserved. There is lower incidence of breast cancer in women who breast feed their infants Reduction in ovarian cancer in women who breast feed their infants Small reduction in type 2 diabetes in women who breast feed their infants EVALUATION OF BENEFITS FOR THE MOTHER

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Early weaning can cause deficiencies Infants can develop: Marasmus: A wasting away of body tissues in the infants first year, caused by severe protein-calorie deficiency Kwashiorkor: A condition caused by a severe deficiency in protein in which the childs abdomen and feet become swollen with water Usually appears between 1 to 3 years of age MALNUTRITION IN INFANCY

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Immunization begins in infancy Accident prevention Increased monitoring needed in infancy Most common accidents in infancy Aspiration of foreign objects Suffocation Falls Poisoning Burns Motor vehicle accidents HEALTH

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Dynamic systems theory: The perspective on motor development that seeks to explain how motor skills are assembled for perceiving and acting When infants are motivated to do something, they might create a new motor behavior Mastering a motor skill requires the infants active efforts to coordinate several components of the skill DYNAMIC SYSTEMS THEORY

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Built-in reactions to stimuli that govern the newborns movements, which are automatic and beyond the newborns control Rooting Sucking Moro Babinski Grasping REFLEXES

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Milestones for large muscle activities Development of posture Learning to walk First year milestones - walks easily Development in second year Skilled and mobile: pull toys, climb stairs Natural exercise: walk quickly, run stiffly GROSS MOTOR SKILLS

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2013 The McGraw-Hill Companies, Inc. All rights reserved. FIGURE 5.16 - MILESTONES IN GROSS MOTOR DEVELOPMENT

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Motor skills that involve finely tuned movements Finely tuned (coordinated) movements Perceptual-motor coupling necessary Finger dexterity (thumb and forefinger) Two types of grasps: Palmar and Pincer Wrists and hands turn and rotate more Experience and exercise have impact FINE MOTOR SKILLS

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2013 The McGraw-Hill Companies, Inc. All rights reserved. SENSATION AND PERCEPTION Sensation: Stimulation of the sense organs. Perception: Interpretation of that stimulation. Process of integrating disjointed sensations into meaningful patterns through perception Measuring Sensation/Perception Habituation/Dishabituation Head movement indicates some vision Visual preference method: Measuring the length of time they attend to different stimuli Tracking - Applied to vision and hearing Technology

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2013 The McGraw-Hill Companies, Inc. All rights reserved. VISION Visual acuity at Birth Estimate of 20/600 Best see objects 7 to 9 inches from eyes Greatest gains in visual acuity between birth and 6 months By about 3 to 5 years of age, approximate adult levels Neonates have poor peripheral vision 30 degree angle; By 7 weeks increases to 45 degrees; By 6 months of age, equal to adult (90 degrees) Able to track movement within one day of birth Preference for moving objects

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2013 The McGraw-Hill Companies, Inc. All rights reserved. VISION Visual accommodation Self-adjustments made by eye lens to bring objects into focus Neonates show little or no visual accommodation Focus on objects 7 to 9 inches away Convergence Does not occur until 7 or 8 weeks Color perception At birth, cones are less well developed than rods Fully mature around 3 months (Distinguish between blue/green) By 4 months can distinguish between similar colors/hues

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Figure 4.5 CONVERGENCE OF THE EYES

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2013 The McGraw-Hill Companies, Inc. All rights reserved. THE LOOKING CHAMBER

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2013 The McGraw-Hill Companies, Inc. All rights reserved. VISUAL PREFERENCES Preferences Moderately complex Movement Contour Infants prefer faces Discriminate maternal and stranger faces Prefer attractive faces Pay most attention to edges

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2013 The McGraw-Hill Companies, Inc. All rights reserved. Preferences for Visual Stimuli in 2-Month-Olds

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2013 The McGraw-Hill Companies, Inc. All rights reserved. MOVEMENTS OF 1- AND 2-MONTH-OLDS

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2013 The McGraw-Hill Companies, Inc. All rights reserved. DEPTH PERCEPTION Depth Perception Develops around 6 months (onset of crawling) Research using the Visual Cliff Gibson and Walk (1960) Heart-rate response to determine fear Relationship between crawling and fear of heights Avoidance of the cliff and infants posture

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2013 The McGraw-Hill Companies, Inc. All rights reserved. HEARING Fetuses respond to sound Can localize sound Startled by loud noises Neonates respond to amplitude and pitch Show preference for mothers voices Responsive to sounds and rhythms of speech Capable of perceiving phonemes of other languages Show no preference for specific languages

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2013 The McGraw-Hill Companies, Inc. All rights reserved. HEARING DeCasper & Spence (1986) Newborns can remember and prefer a story read by mom during the last 6 weeks of pregnancy. Exposed to 3 hours of story.

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2013 The McGraw-Hill Companies, Inc. All rights reserved. DEVELOPMENT OF HEARING By 1 month, infants perceive differences between similar speech sounds By 3 months discriminate caregivers voices Infants perceive most speech sounds present in world languages By 10 to 12 months, lose capacity to discriminate sounds not found in native language By 6 months, they can detect high frequency sounds nearly as well as preschoolers. By 6 months, they can appreciate distance.

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2013 The McGraw-Hill Companies, Inc. All rights reserved. SMELL AND TASTE Smell Well-developed at birth Demonstrate aversion for noxious and preference for pleasant odors Vanilla and Strawberry Recognize familiar odors Recognize mom by 6 days Taste Sensitive to different tastes Demonstrate facial expressions in response to tastes Prefer sweet tastes

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FACIAL EXPRESSIONS ELICITED BY SWEET, SOUR, AND BITTER SOLUTIONS

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2013 The McGraw-Hill Companies, Inc. All rights reserved. TOUCH AND PAIN Touch Sensitive to touch Touch elicits many reflex behaviors Pain Past belief that neonates are not sensitive to pain Neonates not cognitively equipped to ruminate about pain Conditionable distress when confronted with situation that previously presented itself as painful