Physical, Sensory, and Perceptual Development In Infancy

1. Chapter 4: Physical, Sensory, and Perceptual Development In Infancy

2. In This Chapter

3. Physical ChangesThe Brain and Nervous System Brain Rapid development during the first 2 years Midbrain and medulla most fully developed at birth The cortex is the least developed.

4. Figure 4.1 Parts of the Brain

5. The Brain and Nervous SystemPhysical Changes: Synaptic Development

6. The Brain and Nervous SystemPlasticity Neural plasticity: Brain’s ability to change in response to experience Use it or lose it Changes in psychological functioning

7. The Brain and the Nervous SystemMyelinization Myelin: Insulating layer of proteins and fatty substances Description Timing

8. Reflexes and Behavioral StatesAdaptive Reflexes Adaptive reflexes: Reflexes that help survival Warn of possible neuronal development problems when weak or absent Some persist throughout life.

9. Reflexes and Behavioral StatesPrimitive Reflexes Primitive reflexes: Reflexes controlled by less sophisticated parts of brain Should appear at birth and disappear by 6 to 8 months. May indicate neurological problems if persistent.

10. Reflexes and Behavioral StatesStates of Consciousness Sleep, Baby, sleep Patterns of sleep and wakefulness stabilize with age. Neonates sleep 80 percent of the time. By 8 weeks, babies begin to sleep through the night. By 6 months, babies average 14 hours of sleep per day.

11. Reflexes and Behavioral StatesFive States of Sleep and Wakefulness Most infants move through these states in the same sequence every 2 hours

12. Reflexes and Behavioral StatesCrying Baby, Not Crybaby! Cries differ by need. Cross-cultural studies suggest crying increases until 6 weeks then tapers off. Prompt attention to crying in the first 3 months leads to less crying later.

13. Growth, Motor Skills, and Developing Body SystemsPhysical Changes: Growth By age one • 10 to 12 inches of growth • Infants triple body weight Around age two • Toddlers reach half their adult height. • Proportionately much larger heads than adults

14. Growth, Motor Skills, and Developing Body SystemsGrowth and Motor Skills: Overview Inborn timetable of motor skills interacts with other aspects of physical development (Thelen). Muscles, bones, weight—all work together. Opportunities to practice motor skills are important.

15. Stop and Think! Researchers suggest there is a difference in the rate but similarity in the sequence of motor skill development. Using this information as a base, what advice would you give to parents of toddlers?

16. Developing Body Systems and Motor Skills Bones Ossification: Process of hardening of bones • Begins during prenatal development • Continues through puberty • Motor development depends to a large extent on ossification. Changes in number and density of bones are responsible for improved coordination.

17. Developing Body Systems and Motor Skills Muscles Full complement of muscle fibers present at birth • Decline in muscle tissue to fat ratio occurs by age 1. • Change in muscle composition leads to increase in strength.

18. Developing Body Systems and Motor SkillsLungs and Heart Rapid growth during the first 2 years leads to stamina. Ability to sustain motor activity without rest by end of infancy

19. Developing Body Systems and Motor Skills Cross-Cultural Research Experience influences motor development! African motor development • The pattern of traditional cultural practices promotes motor development. • Precocity does not persist into early childhood.

20. ? ? Questions To Ponder Do you or your spouse plan on breastfeeding? What factors would make you want to breastfeed? What factors would cause you not to breastfeed? What are the 3 most important factors that influence physical growth? Why are they important?

21. Health and WellnessNutrition: Breastfeeding and Bottle feeding Breastfeeding Bottle feeding May be needed supplement for preterm babies Special-needs formulas available Can be high quality Allows more father participation • Nutritionally superior: More rapid weight gain and size • Early health benefits • Only nutrition needed for first 4 to 6 months of life • May not be possible for all mothers

22. Health and WellnessNutrition: Solid Food Solid Foods • Early introduction can interfere with nutrition. • Do not help babies to sleep through the night • Should start between 4–6 months Baby is ready for solid foods when he or she can: • Hold head in steady, upright position • Sit with support • Show interest in what you are eating

23. Health and WellnessMalnutrition

24. Health and WellnessHealth Care and Immunization Health Care and Immunizations • Routine health professional visits are important. • Overall health and motor skills are assessed during visits • Vaccinations are given to prevent diseases.

25. Health and WellnessHealth Care and Illness Illnesses in first 2 years • Respiratory illnesses common • Higher in children participating in childcare programs • Chronic ear infections

26. Health and WellnessInfant Mortality Death within the first year of life 7 babies per 1000 in the U.S. Related to prenatal care Varies widely among U.S. ethnic groups Let’s look at Figure 4.3 to examine group differences in infant mortality.

27. Figure 4.2 Group Differences in Infant Mortality

28. Next Let’s Look at Early Prenatal Care and Ethnicity See if you can identify disparities across ethnic groups with regard to access to prenatal care. Do you see any correspondence to these disparities and infant mortality?

29. Figure 4.3 Early Prenatal Care and Ethnicity

30. Health and WellnessSudden Infant Death Syndrome (SIDS) Incidence: Leading cause of death in U.S. in infants 1–12 months Relationships: Apnea Sleeping on stomach Maternal smoking

31. Sensory SkillsVision Rapid development of visual acuity • 20/200 at birth; 20/20 at 2 years Color vision • Red, blue, green at 1 month Tracking • Tracking slow-moving object before 2 months and skilled at 6–10 weeks

32. Sensory Skills Hearing • Adult voices heard well and some directional loud-sound location Smelling and tasting • Newborns react differently to each basic taste as early as birth. Touch and motion • Best developed of all senses

33. Taste Responses in NewbornsWhat responses do you see?

34. Taste Responses in Newborns

35. Stop and Think! In what ways do babies’ sensory skills contribute to the development of the parent–infant relationship?

36. Perceptual SkillsStudying Perceptual Development Preference technique • Study how long baby attends to a particular stimulus. Habituation/dishabituation • Study loss of interest in particular stimulus after repeated exposures. Operant conditioning • Vary the stimulus and study the learned responses.

37. Looking SkillsDepth Perception Depth perception can be judged by: Binocular cues Monocular cues Kinetic cues Do you know the differences among these cues?

38. Depth PerceptionA Walk on the Wild Side—Almost Visual Cliff: Gibson and Walk (1960) Initial findings: 6-month-old babies would not cross the visual cliff. Recent findings: 3-month-olds have some depth perception.

39. Perceptual SkillsWhat Babies Look At: Scanning Visual attention: guided by search for meaningful pattern

40. What Babies Look AtWhat Babies Look At: Faces Face NOT uniquely interesting to infants Attractive faces and mother’s face preferred Before 2 months: Scan edges (hairline, chin) 2–3 months: Scan internal facial features, especially eyes

41. ListeningWhat Babies Hear: Discriminating Speech Sounds 1 month: discriminate between “pa” and “ba” 3 months: respond to male, female, and children’s voices similarly 6 months: discriminate between 2-syllable words 6 months: distinguish sound contrasts in any language; fades by 1 year

42. Perceptual SystemsCombining Information from Several Senses Intermodal perception: Formation of single perception of stimulus that is based on information from 2 or more senses Possible by 1 month Common by 6 months Important in infant learning

43. Perceptual SystemsExplaining Perceptual Development Nativists Empiricists Most perceptual abilities learned Experience needed to develop perceptual systems • Most perceptual abilities inborn • Many of these abilities present at birth A compromise position: Perceptual skill development is the result of interaction between inborn and experiential factors.