Infancy: Physical Development

1. Infancy: Physical Development Physical Growth and Development Teaching Tip: Have students interview parents of infants and toddlers about their children�s physical development. In class, have the students compare and contrast their findings. What might account for any differences? Teaching Tip: Education: Assign students to observe in a local day-care center. If possible, have them observe infants and toddlers and document their observations. What types of gross motor and fine motor tasks are toddlers able to do that infants are not? As a class, have them compile their results. What conclusions can be drawn regarding physical development during infancy and toddlerhood?Teaching Tip: Have students interview parents of infants and toddlers about their children�s physical development. In class, have the students compare and contrast their findings. What might account for any differences? Teaching Tip: Education: Assign students to observe in a local day-care center. If possible, have them observe infants and toddlers and document their observations. What types of gross motor and fine motor tasks are toddlers able to do that infants are not? As a class, have them compile their results. What conclusions can be drawn regarding physical development during infancy and toddlerhood?

2. Sequences of Physical Development Cephalocaudal Development Upper part of the head to the lower parts of the body Proximodistal Development Trunk outward � from body�s central axis toward periphery Truth or Fiction Revisited The head of the newborn child doubles in length by adulthood, but the legs increase in length about five times. (TRUE) Teaching Tip: Nursing & Health: Ask students to bring in pictures or videos of infants and toddlers. Based on these images, have them identify what sequence of development is being demonstrated (cephalocaudal, proximodistal, or differentiation).Truth or Fiction Revisited The head of the newborn child doubles in length by adulthood, but the legs increase in length about five times. (TRUE) Teaching Tip: Nursing & Health: Ask students to bring in pictures or videos of infants and toddlers. Based on these images, have them identify what sequence of development is being demonstrated (cephalocaudal, proximodistal, or differentiation).

3. What Patterns of Growth Occur in Infancy? Weight doubles at about 5 months; triples by first birthday Height increase by 50% in first year Infants grow 4 to 6 inches in second year; and gain 4 to 7 pounds Growth appears continuous but actually occurs in spurts Truth or Fiction Infants triple their birth weight within a year. (TRUE) Teaching Tip: Parenting & Family Studies: Ask students to look at their baby books. If their parents have documented their growth during infancy and toddlerhood, have students compare their growth to the charts available in pediatricians� offices. What might account for their patterns in growth?Truth or Fiction Infants triple their birth weight within a year. (TRUE) Teaching Tip: Parenting & Family Studies: Ask students to look at their baby books. If their parents have documented their growth during infancy and toddlerhood, have students compare their growth to the charts available in pediatricians� offices. What might account for their patterns in growth?

4. Growth Curves for Weight and Height Figure 5.1 Growth Curves for Weight and Height (Length) from Birth to Age 2 Years. The curves indicate the percentiles for weight and length at different ages. Lines labeled 97th show the height and weight of children who are taller and heavier than 97% of children of a particular age. Lines marked 50th indicate the height and weight of the average child of a given age: half their agemates are shorter and lighter, and half are heavier and taller. Lines labeled 3rd designate children who are taller and heavier than only 3% of children their age, and so on. Source: Kuczmarski et al. (2000, Figures 1-4).Figure 5.1 Growth Curves for Weight and Height (Length) from Birth to Age 2 Years. The curves indicate the percentiles for weight and length at different ages. Lines labeled 97th show the height and weight of children who are taller and heavier than 97% of children of a particular age. Lines marked 50th indicate the height and weight of the average child of a given age: half their agemates are shorter and lighter, and half are heavier and taller. Lines labeled 3rd designate children who are taller and heavier than only 3% of children their age, and so on. Source: Kuczmarski et al. (2000, Figures 1-4).

5. Changes in the Proportions of the Body Figure 5.2 Changes in the Proportions of the Body. Development proceeds in a cephalocaudal direction. The head is proportionately larger among younger children.Figure 5.2 Changes in the Proportions of the Body. Development proceeds in a cephalocaudal direction. The head is proportionately larger among younger children.

6. Reflexes Reflexes Simple, unlearned stereotypical responses, elicited by certain types of stimulation Survival vs. Primitive Survival function Neural functioning is determined by testing reflex

7. Reflexes Rooting Baby turns head and mouth toward stimulus that strokes the cheek, chin, or corner of mouth Facilities finding mother�s nipple for sucking Sucking Babies will suck almost any object that touches the lips Will become replaced by voluntary sucking

8. Reflexes Moro or startle reflex Back arches, legs and arms are flung out and then brought back toward chest into a hugging motion Elicited by loud noises or bumping the baby or sudden position changes Grasping or palmar reflex Using four fingers, babies grasp fingers/objects pressed against the palms of their hands Most babies can support their own weight

9. Reflexes Stepping reflex Mimics walking when held under arms Usually disappears by 3 or 4 months Babinski reflex Fans or spreads toes in response to stroking foot Usually disappears at end of first year Tonic-neck reflex While lying on back, baby turns head to one side. Arm and leg on that side extend, while opposite side flex.

10. 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

11. 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

12. 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 Teaching Tip: Education: Have students visit a toy store and locate toys specifically designed for infants. How do these toys encourage visual development? Students might also look online for infant toys. Discuss in class. Teaching Tip: Education: Have students visit a toy store and locate toys specifically designed for infants. How do these toys encourage visual development? Students might also look online for infant toys. Discuss in class.

13. Convergence of the Eyes Figure 4.5 Convergence of the Eyes. Neonates do not have the muscular control to converge their eyes on an object that is close to them. However, they do show some convergence for objects at intermediate viewing distances.Figure 4.5 Convergence of the Eyes. Neonates do not have the muscular control to converge their eyes on an object that is close to them. However, they do show some convergence for objects at intermediate viewing distances.

14. The Looking Chamber Figure 4.4 The Looking Chamber. This chamber makes it easier for the researcher to observe the baby�s eye movements and to record how much time the baby spends looking at a visual stimulus.Figure 4.4 The Looking Chamber. This chamber makes it easier for the researcher to observe the baby�s eye movements and to record how much time the baby spends looking at a visual stimulus.

15. Visual Preferences Preferences Moderately complex Movement Contour Infants prefer faces Discriminate maternal and stranger faces Prefer attractive faces Pay most attention to edges Teaching Tip: Parenting & Family Studies: Ask students to explore the variety of toys available for infants. Based on what is known about infant vision, what types of toys are best to encourage visual tracking, visual acuity, and visual interest?Teaching Tip: Parenting & Family Studies: Ask students to explore the variety of toys available for infants. Based on what is known about infant vision, what types of toys are best to encourage visual tracking, visual acuity, and visual interest?

16. Preferences for Visual Stimuli in 2-Month-Olds Figure 5.12 Preferences for Visual Stimuli in 2-Month-Olds. Infants appear to prefer complex to simple visual stimuli. By the time they are 2 months old, they also tend to show preference for the human face. Researchers continue to debate whether the face draws attention because of its content (i.e., being a face) or because of its stimulus characteristics (complexity, arrangement, etc.)Figure 5.12 Preferences for Visual Stimuli in 2-Month-Olds. Infants appear to prefer complex to simple visual stimuli. By the time they are 2 months old, they also tend to show preference for the human face. Researchers continue to debate whether the face draws attention because of its content (i.e., being a face) or because of its stimulus characteristics (complexity, arrangement, etc.)

17. Eye Movements of 1- and 2-Month-Olds Figure 5.13 Eye Movements of 1- and 2-Month-Olds. One-month-olds direct their attention to the edges of objects. Two-month-olds �move in from the edge.� When looking at a face, for example, they focus on the eyes and other inner features. Source: Salapatek (1975.)Figure 5.13 Eye Movements of 1- and 2-Month-Olds. One-month-olds direct their attention to the edges of objects. Two-month-olds �move in from the edge.� When looking at a face, for example, they focus on the eyes and other inner features. Source: Salapatek (1975.)

18. 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 Truth or Fiction Infants need to have experience crawling before they develop fear of heights. (Mixed Evidence) Teaching Tip: Ask students to explore the Internet for videos of the visual cliff experiment. Show the videos in class and discuss the implication of these studies on what is known about the development of depth perception in infancy. What implications might these studies have on what is known about the transmission of fear from parent to child?Truth or Fiction Infants need to have experience crawling before they develop fear of heights. (Mixed Evidence) Teaching Tip: Ask students to explore the Internet for videos of the visual cliff experiment. Show the videos in class and discuss the implication of these studies on what is known about the development of depth perception in infancy. What implications might these studies have on what is known about the transmission of fear from parent to child?

20. 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 Teaching Tip: Ask students to bring in songs designed specifically for infants. If possible, have them bring songs from different countries. How are these songs similar and/or different? How do these songs demonstrate what we know about hearing in infants? Teaching Tip: Ask students to bring in songs designed specifically for infants. If possible, have them bring songs from different countries. How are these songs similar and/or different? How do these songs demonstrate what we know about hearing in infants?

21. 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. Teaching Tip: Ask students to bring in songs designed specifically for infants. If possible, have them bring songs from different countries. How are these songs similar and/or different? How do these songs demonstrate what we know about hearing in infants? Teaching Tip: Ask students to bring in songs designed specifically for infants. If possible, have them bring songs from different countries. How are these songs similar and/or different? How do these songs demonstrate what we know about hearing in infants?

22. A Neonate Sucking to Hear Her Mother�s Voice Figure 4.7 A Neonate Sucking to Hear Her Mother�s Voice. Figure 4.7 A Neonate Sucking to Hear Her Mother�s Voice.

23. 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. Teaching Tip: Education: Ask students to interview a speech and language pathologist who works with young children. Discuss what, if anything, can be done to detect language delays in infancy. Teaching Tip: Parenting & Family Studies: How might a family know that their child is experiencing hearing problems or language delays? What can be done to prevent and treat these delays? Have students discuss these issues in class.Teaching Tip: Education: Ask students to interview a speech and language pathologist who works with young children. Discuss what, if anything, can be done to detect language delays in infancy. Teaching Tip: Parenting & Family Studies: How might a family know that their child is experiencing hearing problems or language delays? What can be done to prevent and treat these delays? Have students discuss these issues in class.

24. 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 Teaching Tip: Have students discuss why infants may have inborn preferences for certain tastes? How might these inborn preferences shape their preferences for foods in later development?Teaching Tip: Have students discuss why infants may have inborn preferences for certain tastes? How might these inborn preferences shape their preferences for foods in later development?

25. Facial Expressions Elicited by Sweet, Sour, and Bitter Solutions Figure 4.6 Facial Expressions Elicited by Sweet, Sour, and Bitter Solutions. Neonates are sensitive to different tastes, as shown by their facial expressions when tasting (a) sweet, (b) sour, and (c) bitter solutions.Figure 4.6 Facial Expressions Elicited by Sweet, Sour, and Bitter Solutions. Neonates are sensitive to different tastes, as shown by their facial expressions when tasting (a) sweet, (b) sour, and (c) bitter solutions.

26. 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 Teaching Tip: Discuss the pros and cons of circumcision during infancy. How does what is known about infants and pain shape decisions regarding early medical procedures? Teaching Tip: Discuss the pros and cons of circumcision during infancy. How does what is known about infants and pain shape decisions regarding early medical procedures?

27. Development of the Brain and Nervous System

28. 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

29. Anatomy of a Neuron Figure 5.3 Anatomy of a Neuron. �Messages� enter neurons though dendrites, are transmitted along the axon, and then are sent through axon terminals to muscles, glands, and other neurons. Neurons develop via proliferation of dendrites and axon terminals and myelination. See your student companion website for an interactive version of Figure 5.3Figure 5.3 Anatomy of a Neuron. �Messages� enter neurons though dendrites, are transmitted along the axon, and then are sent through axon terminals to muscles, glands, and other neurons. Neurons develop via proliferation of dendrites and axon terminals and myelination. See your student companion website for an interactive version of Figure 5.3

30. Brain Development Growth Spurts in Brain Development Prenatal - during 4th and 5th months Proliferation of neurons 25th week prenatal through end of second year after birth Proliferation of dendrites and axon terminals

31. How Do Neurons Develop? As child matures Cells grow in size and weight. 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 Neurotransmitters Increases during infancy. Receptors continue specialization. Teaching Tip: Assign students to small groups and have them develop a nonlinguistic representation of the process of myelination. Present these in class and have students evaluate them in terms of clarity. Would someone who is not familiar with myelination understand how it function by viewing these representations? Technology Tip: Have students find out more about current research on the causes and treatment of multiple sclerosis on the National Multiple Sclerosis Society website. URL: http://www.nationalmssociety.org/index.aspxTeaching Tip: Assign students to small groups and have them develop a nonlinguistic representation of the process of myelination. Present these in class and have students evaluate them in terms of clarity. Would someone who is not familiar with myelination understand how it function by viewing these representations? Technology Tip: Have students find out more about current research on the causes and treatment of multiple sclerosis on the National Multiple Sclerosis Society website. URL: http://www.nationalmssociety.org/index.aspx

32. Increases in Neural Connections in the Brain Figure 5.6 Increases in Neural Connections in the Brain. A major growth spurt in the brain occurs between the 25th week of the prenatal development and the end of the second year after birth. This growth spurt is due primarily to the proliferation of dendrite and axon terminals. Source: Conel (1959).Figure 5.6 Increases in Neural Connections in the Brain. A major growth spurt in the brain occurs between the 25th week of the prenatal development and the end of the second year after birth. This growth spurt is due primarily to the proliferation of dendrite and axon terminals. Source: Conel (1959).

33. The Brain Command center of organism Brain of neonate weighs less than one pound By first birthday, the brain triples in weight, reaching nearly 70% of adult weight Truth or Fiction Revisited A child�s brain reaches half of its adult weight by the age of 1 year. (TRUE) Truth or Fiction Revisited A child�s brain reaches half of its adult weight by the age of 1 year. (TRUE)

34. Growth of Body Systems as a Percentage of Total Postnatal Growth Figure 5.4 Growth of Body Systems as a Percentage of Total Postnatal Growth. The brain of the neonate weighs about one-fourth its adult weight. In keeping with the principle of cephalocaudal growth, it will triple in weight by the first birthday, reaching nearly 70% of its adult weight.Figure 5.4 Growth of Body Systems as a Percentage of Total Postnatal Growth. The brain of the neonate weighs about one-fourth its adult weight. In keeping with the principle of cephalocaudal growth, it will triple in weight by the first birthday, reaching nearly 70% of its adult weight.

35. How Do Nature and Nurture Affect the Development of the Brain? Brain development is affected by maturation (nature) and sensory stimulation and motor activity (nurture) Rats in enriched environment More synapses per neuron Human infants have more neural connections than adults If activated by experience, connection survives If not activated, connection does not survive Adequate nutrition is necessary Teaching Tip: Parenting & Family Studies: Based on what is known about the role of nurture in brain development, have students develop some recommendations for families of young children. What should parents do to stimulate brain growth (give specific examples)?Teaching Tip: Parenting & Family Studies: Based on what is known about the role of nurture in brain development, have students develop some recommendations for families of young children. What should parents do to stimulate brain growth (give specific examples)?

36. Nutritional Needs of Children Infants require breast milk or iron fortified formula Solid foods may be introduced about 4 to 6 months Iron-enriched cereal, strained fruits, vegetables, and meats Whole cow�s milk delayed until 9 to 12 months Teaching Tip: Social Work & Counseling: Ask students to investigate local agencies that provide nutritional help for infants and families. If possible, ask a local representative to come to class and describe the program.Teaching Tip: Social Work & Counseling: Ask students to investigate local agencies that provide nutritional help for infants and families. If possible, ask a local representative to come to class and describe the program.

37. Why Do Women Bottle-feed or Breastfeed their Children? Choice to breastfeed is influenced by Domestic and occupational arrangements Attitudes regarding benefits for bonding and infant health Fear of pain, unease with breastfeeding, and public breastfeeding Community and familial support Level of education Colostrum early form of breast milk High level of nutrients into low volume Technology Tip: Have students find out more information about the advantages of breast feeding on the La Leche League International website. Also, have them find out whether their community has a local chapter. URL: http://www.lli.org Teaching Tip: What should companies do to support nursing mothers? Have students consider policies, facilities, time, and other factors. Teaching Tip: Nursing & Health: Have students find out more about colostrum and its role in infant health. Discuss their findings in class.Technology Tip: Have students find out more information about the advantages of breast feeding on the La Leche League International website. Also, have them find out whether their community has a local chapter. URL: http://www.lli.org Teaching Tip: What should companies do to support nursing mothers? Have students consider policies, facilities, time, and other factors. Teaching Tip: Nursing & Health: Have students find out more about colostrum and its role in infant health. Discuss their findings in class.

38. Advantages of Breast Milk Some advantages of breast milk Conforms to digestion process Possesses needed nutrients Contains mother�s antibodies Protects against childhood lymphoma, ear infections, etc. Helps protect against infant diarrhea Is less likely than formula to cause allergies Helps prevent obesity later in life Maternal health benefits Human newborns prefer it Truth or Fiction Breastfeeding helps prevent obesity later in life. (TRUE) Teaching Tip: Nursing & Health: Have students discuss the role of breast milk in preventing later obesity. What factors could be related to this correlation? Teaching Tip: Invite a local lactation consultant to come to class to discuss her job. Have students generate a list of questions prior to the visit. Technology Tip: Have students visit the International Lactation Consultation Association website to find out more about this career and their role in encouraging breastfeeding across the world. URL: http://www.ilca.org/i4a/pages/index.cfm?pageid=1Truth or Fiction Breastfeeding helps prevent obesity later in life. (TRUE) Teaching Tip: Nursing & Health: Have students discuss the role of breast milk in preventing later obesity. What factors could be related to this correlation? Teaching Tip: Invite a local lactation consultant to come to class to discuss her job. Have students generate a list of questions prior to the visit. Technology Tip: Have students visit the International Lactation Consultation Association website to find out more about this career and their role in encouraging breastfeeding across the world. URL: http://www.ilca.org/i4a/pages/index.cfm?pageid=1

39. Disadvantages of Breast Milk Disadvantages of breast milk HIV, alcohol, drugs, and environmental hazards may be transmitted through breast milk Mother must be adequately nourished Physical demands on mother What about mothers who smoke? No harmful effects on infants have been noted

40. Motor Development

41. What Is Motor Development? Developments in the activity of muscles, and changes in posture, movement, and coordination Follows cephalocaudal and proximodistal patterns Lifting and holding head before torso Voluntary reaching Locomotion Sequence � Rolling over, sitting, crawling, creeping, walking, running

42. Control of the Hands Newborns track objects with eyes but do not reach for them Grasp reflex Grasp but do not release intentionally Voluntary grasping Ulnar grasp Pincer grasp Visual � motor coordination Teaching Tip: Invite a local pediatric occupational therapist to come to class to talk about his or her role in working with fine motor problems in young children. Teaching Tip: Invite a local pediatric occupational therapist to come to class to talk about his or her role in working with fine motor problems in young children.

43. Pincer Grasp Figure 5.7 Pincer Grasp. Infants first hold objects between their fingers and palm. Once the oppositional thumb comes into play at about 9 to 12 months of age, infants are able to pick up tiny objects using what is termed a pincer grasp.Figure 5.7 Pincer Grasp. Infants first hold objects between their fingers and palm. Once the oppositional thumb comes into play at about 9 to 12 months of age, infants are able to pick up tiny objects using what is termed a pincer grasp.

44. Locomotion Moving from one place to another Sequence with variation in ages of initiation Roll over, sit, crawl, creep, walk (supported and unaided) Muscle strength, density of bones, balance, and coordination improve Climb steps, run, walk backward, kick a ball, jump Teaching Tip: Education: Have students observe in a local day-care center and record what types of gross motor activities they observe in infants and toddlers. What is done in the center to encourage gross motor activities?Teaching Tip: Education: Have students observe in a local day-care center and record what types of gross motor activities they observe in infants and toddlers. What is done in the center to encourage gross motor activities?

45. Motor Development in Infancy Figure 5.8 Motor Development in Infancy. Motor development proceeds in an orderly sequence, but there is considerable variation in the timing of the marker events shown in this figure. An infant who is a bit behind will most likely develop without problems, and a precocious infant will not necessarily become a rocket scientist (or gymnast).Figure 5.8 Motor Development in Infancy. Motor development proceeds in an orderly sequence, but there is considerable variation in the timing of the marker events shown in this figure. An infant who is a bit behind will most likely develop without problems, and a precocious infant will not necessarily become a rocket scientist (or gymnast).

46. Creeping Figure 5.9 Creeping. Creeping requires considerable coordination of arm and leg movements. Creeping usually appears a month or so after crawling.Figure 5.9 Creeping. Creeping requires considerable coordination of arm and leg movements. Creeping usually appears a month or so after crawling.

47. Walking Figure 5.10 Walking. By 12 to 15 months or so, babies walk by themselves, earning them the name toddler.Figure 5.10 Walking. By 12 to 15 months or so, babies walk by themselves, earning them the name toddler.

48. What Are the Roles of Nature and Nurture in Motor Development? Maturation (nature) Myelination and differentiation is needed for certain voluntary motor activities Experience (nurture) Experimentation to achieve milestones Slight effect in training to accelerate motor skills Reaction range Limits for the expression of inherited traits Truth or Fiction Revisited Native American Hopi infants spend the first year of life strapped to a board, yet they begin to walk at about the same time as children who are reared in other cultures. (TRUE)Truth or Fiction Revisited Native American Hopi infants spend the first year of life strapped to a board, yet they begin to walk at about the same time as children who are reared in other cultures. (TRUE)

49. Native American Hopi Infant Strapped to a Cradle Board Figure 5.11 A Native American Hopi Infant Strapped to a Cradle Board. Researchers have studied Hopi children who are strapped to cradle boards during their first year to see whether their motor development is significantly delayed. Once released from their boards, Hopi children advance rapidly in their motor development, suggesting the important role of maturation in motor development.Figure 5.11 A Native American Hopi Infant Strapped to a Cradle Board. Researchers have studied Hopi children who are strapped to cradle boards during their first year to see whether their motor development is significantly delayed. Once released from their boards, Hopi children advance rapidly in their motor development, suggesting the important role of maturation in motor development.