1. Chapter 5 Infancy: Physical Development

2. Infancy: Physical Development: Truth or Fiction?
The head of the newborn child doubles in length by adulthood, but the legs increase in length about five times.
Infants triple their birth weight within a year.

3. Infancy: Physical Development: Truth or Fiction?
Breastfeeding helps prevent obesity later in life.
A child’s brain reaches half of its adult weight by the age of 1 year.

4. Infancy: Physical Development: Truth or Fiction?
The cerebral cortex – the outer layer of the brain that is vital to human thought and reason – is only one-eighth of an inch thick.
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.

5. Infancy: Physical Development: Truth or Fiction?
Infants need to have experience crawling before they develop fear of heights.

6. Infancy: Physical Development
Physical Growth and Development

7. What are the 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
Differentiation
Tendency of behavior to become more specific and distinct

8. 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

9. Figure 5.1 Growth Curves for Weight and Height (Length) from Birth to Age 3 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. (Source: Figures 1-4, Kuczmarski, R.J., et.al. [2000, December 4]. CDC Growth charts: United States. Advance data from vital and health statistics, no Hyattsville, MD: National Center for Health Statistics.)
Figure 5.1 Growth Curves for Weight and Height (Length) From Birth to Age 2 Years

10. Figure 5.2 Changes in the Proportions of the Body
Figure 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

11. What is Failure to Thrive?
Growth impairment during infancy and early childhood
Causes may be organic or non-organic
Biologically based or non-biologically based
Links to physical, cognitive, behavioral and emotional problems
Deficiencies in caregiver-child interaction may play a role
Canalization – catch up growth once FTT is resolved

12. What are the 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
Teething biscuits in later part of first year

13. Guidelines for Infant Nutrition
Build up variety of foods
Avoid overfeeding or underfeeding
Don’t restrict fat and cholesterol
Don’t overdo high-fiber foods
Avoid items with added sugar and salt
Encourage high-iron foods
U.S. Dept of Agriculture, 2000

14. Developing in a World of Diversity
Alleviating Protein-Energy Malnutrition (PEM)

15. Why do Women Bottle-feed or Breastfeed their Children?
Choice to breastfeed is influenced by
Attitudes regarding benefits for bonding and infant health
Fear of pain, unease with breastfeeding and public breastfeeding
Domestic and occupational arrangements
Community and familial support
Level of education

16. What are the Advantages and Disadvantages of Breast Milk?
Conforms to digestion process
Possesses needed nutrients
Contains mother’s antibodies
Helps protect against infant diarrhea
Is less likely, than formula, to cause allergies
Disadvantages of breast milk
HIV, alcohol, drugs and environmental hazards may be transmitted through breast milk
Physical demands on mother

17. Development of the Brain and Nervous System

18. 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

19. Figure 5.3 Anatomy of a Neuron
Figure 5.3 The 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.
Figure 5.3 Anatomy of a Neuron

20. How do Neurons Develop? As child matures Myelin Sheaths
Axons grow in length
Dendrites and axon terminals proliferate
Connection networks become more complex
Myelin Sheaths
Makes messages more efficient
Myelination occurs with maturation
Inhibition of myelination results in disease

21. What is 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

22. Figure 5.4 The 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

23. Structures of the Brain
Medulla
Controls basic body functions - heartbeat, respiration
Cerebellum
Maintains balance, control motor behavior, coordinate eye movements with body sensations
Cerebrum
Allows human learning, thought, memory and language

24. Figure 5.5 Structures of the Brain
Figure 5.5 Structures of the Brain. The convolutions of the cortex increase its surface area, and apparently, its intellectual capacity. (In this case, wrinkles are good). The medulla is involved in vital functions such as respiration and heartbeat; the cerebellum is involved in balance and coordinator.
Figure 5.5 Structures of the Brain

25. How Does the Brain Develop?
Growth Spurts in Brain Development
Prenatal – fourth and fifth months
Proliferation of neurons
Prenatal – 25th week through 2 years old
Proliferation of dendrites and axon terminals

26. Figure 5.6 Increase 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.
Figure 5.6 Increase in Neural Connections in the Brain

27. Brain Development in Infancy
Myelination
At birth brain areas well myelinated include
Heartbeat and respiration
Sleeping and arousal
Reflex activity
Myelination of sensory areas
Hearing – begins about 6th month of pregnancy and continues to age 4
Vision – begins shortly before full term but develop rapidly

28. 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 dendrites and axon terminals
Human infants have more neural connections than adults
If activated by experience, connection survives
If not activated, connection does not survive

29. Motor Development

30. What is Motor Development?
Developments in the activity of muscles, and is connected with changes in posture, movement, and coordination
Follows cephalocaudal and proximodistal patterns
Lifting and holding head before torso
Voluntary reaching
Locomotion
Sequence: rolling over, sitting up, crawling, creeping, walking, running

31. What is Motor Development?

32. 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

33. Sensory and Perceptual Development

34. How do Sensation and Perception Develop in the Infant?
Process of integrating disjointed sensations into meaningful patterns through perception
Focus on vision and hearing
Most research is one these areas

35. Development of Visual Acuity and Peripheral Vision
Neonates are nearsighted
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
Perceive stimuli within 30 degree angle
By 7 weeks increases to 45 degrees
By 6 months of age, equal to adult

36. What Captures the Attention of Infants
What Captures the Attention of Infants? How do Visual Preferences Develop?
Neonates attend longer to stripes than blobs
By 8 to 12 weeks, prefer curved lines over straight
Infants prefer faces
Discriminate maternal and stranger faces
Prefer attractive faces
Pay most attention to edges

37. Figure 5.11 Preferences in Visual Stimuli in 2-Month-Olds
Figure 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 (that is, being a face) or because of its stimulus characteristics (complexity, arrangement, etc.)
Figure 5.11 Preferences in Visual Stimuli in 2-Month-Olds

38. Figure 5.12 Eye Movements of 1- and 2-Month Olds
Figure 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.) How do researchers explain this change?
Figure 5.12 Eye Movements of 1- and 2-Month Olds

39. How do Researchers Determine Whether Infants will “Go Off the Deep End”?
Depth Perception
Develops around 6 months (onset of crawling)
Research using the Visual Cliff
Gibson and Walk (1960)
Relationship between crawling and fear of heights

40. Figure 5.13 The Visual Cliff
Figure The Visual Cliff. This young explorer has the good sense not to crawl out onto an apparently unsupported surface, even when mother beckons from the other side. Do infants have to experience some of life’s “bumps” before they avoid going off the deep end?”
Figure 5.13 The Visual Cliff

41. What are Perceptual Constancies? How do they Develop?
Perceptual constancy – perception of object remains stable although sensations may differ under various conditions
Size constancy – perception of object’s size remains stable although retinal size may differ
Appears by 2 1/2 to 3 months
Shape constancy – perception of object‘s shape remains stable although shape on retina may change
Appears by 4 to 5 months

42. Strategies for Studying the Development of Shape Constancy
A Closer Look
Strategies for Studying the Development of Shape Constancy

43. What are Perceptual Constancies? How do they Develop?
Perceptual constancy – perception of object remains stable although sensations may differ under various conditions
Size constancy – perception of object’s size remains stable although retinal size may differ
Appears by 2 1/2 to 3 months
Shape constancy – perception of object‘s shape remains stable although shape on retina may change
Appears by 4 to 5 months

44. How Does the Sense of Hearing Develop in Infancy?
Neonates can orient toward direction of a sound
18 months locate sounds as well as adults
By 3 1/2 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

45. Figure Declining Ability to Discriminate the Sounds of Foreign Languages. Infants show a decline in the ability to discriminate sounds not found in their native language. Before 6 months of age, infants from English-speaking families could discriminate sounds found in Hindi (red bars) and Salish, a Native American language (green bars). By 10 to 12 months of age, they could no longer do so. (Source: Werker, 1989)
Figure 5.14 Declining Ability to Discriminate the Sounds of Foreign Languages

46. Effects of Early Exposure to Garlic, Alcohol, and – Gulp - Veggies
A Closer Look
Effects of Early Exposure to Garlic, Alcohol, and – Gulp - Veggies

47. Do Children Play an Active or Passive Role in Perceptual Development?
Neonates perception is largely passive
Later, intentional action replaces capture
Systematic search replaces unsystematic
Attention becomes selective
Irrelevant information gets ignored

48. What is the Evidence for the Roles of Nature and Nurture in Perceptual Development?
Sensory changes are linked to maturation of nervous system (Nature)
Experience also plays a role (Nurture)
Critical periods
Newborn kittens with patched eye – become blind in that eye
Nature and nurture interact to shape perceptual development.

49. Lessons in Observation Sensation and Perception in Infancy
What does research tell us about the sensory capacities of newborns, such as Carter and Aiden? Cite evidence from the video that supports this research in regard to vision and hearing.
Slide 05:48 (Chapter 5, Slide 48)
Slide was omitted in original chapter presentation

50. Lessons in Observation Sensation and Perception in Infancy
Slide 05:48 (Chapter 5, Slide 48)
Slide was omitted in original chapter presentation

51. Lessons in Observation Sensation and Perception in Infancy
Discuss how the newborn’s capacities for vision and hearing are adaptive in the context of Carter’s initial interaction with mom.
Infants have clear visual preferences. Discuss the visual preferences of infants in the context of the response of 2-month-old Giuseppina to the stimuli presented by Dr. Basow. What method is Dr. Basow using as a test of Giuseppina’s visual preferences? What other methods are commonly used to study infant sensory and perceptual capacities?

52. Lessons in Observation Sensation and Perception in Infancy
Does the newborn’s preference for looking at faces more than at other objects indicate that form perception is innate? Why or why not?