1. Chapter 4: Physical Development in Infancy ©2009 The McGraw-Hill Companies, Inc. All rights reserved. Life-Span Development Twelfth Edition

2.  Patterns of Growth:  Cephalocaudal Pattern: sequence in which the earliest growth always occurs from the top downward ▪Also applies to gains in motor development  Proximodistal Pattern: sequence in which growth starts in the center of the body and moves toward the extremities ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

3.  Height and Weight:  Average North American newborn is 20 inches long and 7 ½ pounds ▪95% of full-term newborns are 18-22 inches long and weigh between 5 ½ and 10 lbs. ▪Newborns lose 5-7% of their body weight in the first few days of life ▪They typically gain 5-6 ounces per week during the first month  Weight usually triples by their 1 st birthday ▪Newborns gain approximately 1 inch per month during the first year  Growth slows considerably during the 2 nd year ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

5.  The Brain:  Brain continues developing past infancy  Shaken Baby Syndrome: brain swelling and hemorrhaging from child abuse trauma  Brain imaging technologies cannot typically be used with babies ▪EEGs show regular spurts in the brain’s electrical activity ▪Spurts may coincide with important changes in cognitive development  At birth, the brain is 25% of its adult weight; at 2 years of age, it is 75% of its adult weight ▪The brain does not mature uniformly ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

6.  Forebrain: portion of the brain farthest from the spinal cord; includes cerebral cortex  Cerebral Cortex: folded surface covering the forebrain  Cerebral cortex is divided into 2 hemispheres, each with 4 lobes ▪Frontal lobe: voluntary movement, thinking, personality, and intentionality ▪Occipital lobe: vision functions ▪Temporal lobe: hearing, language processing, and memory ▪Parietal lobe: spatial location, attention, and motor control ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

7.  Lateralization: specialization of function in one hemisphere of the cerebral cortex or the other  Some functions are lateralized, some are not ▪Complex functions involve communication between both hemispheres ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

9.  Neurons: brain nerve cells that communicate through electrical and chemical signals  Axons carry signals away from the cell body  Dendrites carry signals toward the cell body  Myelin sheath is a layer of fat cells that insulate axons ▪Helps electrical signals travel faster  Terminal buttons release chemicals (neurotransmitters) into synapses ▪Synapses: tiny gaps between neurons ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

11.  Changes in Neurons:  Myelination: the process of encasing axons with fat cells ▪Begins prenatally and continues into adolescence  Connectivity among neurons increases ▪New dendrites grow ▪Connections among dendrites increase ▪Synaptic connections increase  More synaptic connections are created than will ever be used ▪Leads to a “pruning” of unused connections ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

13.  Changes in regions of the brain:  “Blooming and pruning” of synapses varies by brain region  Pace of myelination varies as well ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

14.  Depressed brain activity has been found in children who grow up in a deprived environment  Enriched environments promote faster brain development than deprived ones  After birth: sights, sounds, smells, touches, language, and eye contact help shape the brain’s neural connections  Repeated experience wires (and rewires) the brain  Brain is both flexible and resilient ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

16.  Typical newborns sleep 16-17 hours per day  Infants vary in their preferred times for sleeping  Most have moved closer to adult-like sleep patterns by 4 months of age  Factors involved in night waking:  Daytime crying and fussing  Distress when separated from mother  Breast feeding  Co-sleeping ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

17.  Cultural variations influence infant sleeping patterns  Babies average much more REM sleep than do older children or adults  REM sleep may provide infants with added self- stimulation  REM sleep may also promote brain development  We do not know whether infants dream or not ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

19.  The practice of shared sleeping, in which a newborn shares a bed with mother, varies among cultures  Potential benefits:  Promotes breast feeding and a quicker response to crying  Allows mother to detect potentially dangerous breathing pauses in baby  American Academy of Pediatrics discourages shared sleeping  Increases risk of injury (rolling over baby) and SIDS ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

20.  SIDS (Sudden Infant Death Syndrome): infants stop breathing and die without apparent cause  Highest cause of infant death in U.S. annually  Highest risk is 2-4 months of age  Risk decreases when infant sleeps on its back and when a pacifier is used ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

21.  Other risk factors associated with SIDS:  Siblings who died from SIDS  Sleep apnea or low birth weight  Infants passively exposed to cigarette smoke  Being from lower SES or being African American or Eskimo  Infants placed in soft bedding  Infants with abnormal brain stem functioning involving serotonin ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

22.  Experts recommend that infants consume 50 calories per day for each pound they weigh  U.S. parents typically do not feed infants enough fruits and vegetables  By 15 months, French fries are the most common vegetable eaten  Increasing rates of overweight and obese infants  Other factors: ▪Mother’s weight gain during pregnancy and pre-pregnancy weight ▪Breast feeding vs. bottle feeding ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

24.  American Academy of Pediatrics strongly endorses breast feeding throughout the first year  Benefits for baby can include:  Fewer gastrointestinal and lower respiratory tract infections  Potentially decreased risk of asthma  Less likely to become overweight or obese  Less incidence of diabetes  Less likely to experience SIDS ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

25.  Benefits for mother can include:  Lower incidence of breast and ovarian cancer  Lower incidence of Type 2 diabetes  Breast feeding does not:  Help mother return to pre-pregnancy weight  Guard against osteoporosis  Decrease likelihood of experiencing post-partum depression ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

26.  Women less likely to breast feed:  Mothers who work full-time outside of the home  Mothers under age 25  Mothers without a high school education  African-American mothers  Mothers in low-income circumstances ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

27.  Mother should not breast feed if:  She has AIDS or other infectious diseases that can be transmitted through milk  She has active tuberculosis  She is taking a drug that may not be safe for the infant  No psychological differences have been found between breast-fed and bottle-fed infants  Most breast- vs. bottle-feeding studies are correlational and do not imply causation ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

28.  Malnutrition in Infancy:  Early weaning and inadequate sources of nutrients can cause malnutrition  Marasmus: a severe protein-calorie deficiency ▪Results in a wasting away of body tissues  Kwashiorkor: a severe protein deficiency that causes the abdomen and feet to swell with water ▪Causes the vital organs to collect nutrients, depriving other parts of the body  Severe and lengthy malnutrition is detrimental to physical, cognitive, and social development ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

29.  Dynamic Systems View:  Infants assemble motor skills for perceiving and acting ▪Motor skills represent solutions to goals  Development is an active process in which nature and nurture work together ▪Development of nervous system ▪Body’s physical properties and possibilities for movement ▪Goal the child is motivated to reach ▪Environmental support for the skill ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

30.  Reflexes: built-in reactions to stimuli; generally carry survival mechanisms  Rooting Reflex: when the infant’s cheek is stroked, the infant will turn its head to the side that was touched  Moro Reflex: automatic arching of back and wrapping of arms to center of body when startled  Grasping Reflex: infant’s hands close around anything that touches the palms  Some reflexes continue throughout life; others disappear several months after birth ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

31.  Gross Motor Skills: skills that involve large-muscle activities  Walking, grabbing for objects  Gross motor skills require postural control  Posture is a dynamic process linked with sensory information in the skin, joints, and muscles  Infants can produce stepping movements needed for walking from a very early age  They lack the ability to stabilize balance on one leg at a time  Infants learn what kinds of places and surfaces are safe for locomotion ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

33.  Development in the 2 nd Year:  Toddlers become more skilled and mobile  Motor activity is vital to the child’s development of competence and independence  By 18-24 months, toddlers can: ▪Walk quickly or run stiffly ▪Balance on their feet in a squat position ▪Walk backward ▪Stand and kick a ball without falling ▪Jump in place ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

34.  Cultural Variations: mothers in developing countries tend to stimulate their infants’ motor skills more than mothers in more modern countries  Infants can reach motor milestones slightly earlier if provided with physical guidance or given opportunities for exercise  Even when activity is restricted, many infants still reach milestones at a normal age ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

35.  Fine Motor Skills: involve finely tuned movements  Reaching and grasping is a significant milestone for infants  Palmer grasp: grasping with the whole hand  Pincer grip: grasping with the thumb and forefinger  Perceptual-motor coupling is necessary for infants to coordinate grasping  Experienced infants look at objects longer, reach for them more, and are more likely to mouth the objects ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

36.  Sensation: occurs when information interacts with sensory receptors (eyes, ears, tongue, nostrils, and skin)  Perception: the interpretation of what is sensed  Ecological View: we directly perceive information that exists in the world around us  The perceptual system selects from the rich information provided by the environment  Perception enables interaction with, and adaptation to, one’s environment ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

37.  Affordances: opportunities for interaction offered by objects that fit within our capabilities to perform activities  What affordances can infants or children detect and use? ▪Children become more efficient at discovering and using affordances through perceptual development ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

38.  Visual Preference Method: infants look at different things for different lengths of time  They look at preferred objects longer  Habituation: decreased responsiveness to a stimulus after repeated presentations  Dishabituation: recovery of a habituated response after a change in stimulation ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

40.  Habituation and Dishabituation Studies:  High-amplitude sucking  Orienting response  Tracking  Videotaping  Recording heart rate, respiration, body movement, sucking behavior, visual fixation ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

41.  Newborn’s vision is about 20/600 (an object 20 feet away appears as if it were 600 feet away)  By the age of 6 months, vision is 20/100 or better  Vision approximates that of an adult by the infant’s first birthday  Infants show an interest in human faces soon after birth  The way they gather information about the visual world changes rapidly with age ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

44.  Perceptual Constancy: sensory stimulation is changing but perception of the physical world remains constant  Size Constancy: recognition that an object remains the same even though the retinal image of the object changes ▪Babies as young as 3 months show size constancy ▪Continues to develop until 10 or 11 years old  Shape Constancy: recognition that an object remains the same shape even though its orientation to us changes ▪3-month-olds show shape constancy, but not for irregularly shaped objects ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

45.  Eleanor Gibson and Richard Walk studied development of depth perception using a “visual cliff”  Infants 6-12 months old can distinguish depth  Infants 2-4 months old show heart rate difference when placed on deep side of cliff  Infants develop binocular depth cues by about 3- 4 months of age ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

47.  Fetuses can hear and learn sounds during the last two months of pregnancy and can recognize their mother’s voice at birth  Newborns:  Cannot hear soft sounds as well as adults  Are less sensitive to pitch  Are fairly good at determining the location of a sound ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

48.  Touch and Pain: newborns respond to touch and can feel pain  Smell: newborns can differentiate odors ▪Preference for mother’s smell by 6 days  Taste: sensitivity to taste may be present before birth ©2009 The McGraw-Hill Companies, Inc. All rights reserved.

49.  Intermodal Perception: the ability to integrate information from two or more sensory modalities  Babies are born with some innate abilities to perceive relations among senses  Their abilities improve considerably through experience  Perceptual–Motor Coupling: action guides perception, and perception guides action ©2009 The McGraw-Hill Companies, Inc. All rights reserved.