1. Unit 2: Infant and Toddler Development Wendy DuCassé, MSW, LCSW * Power Point slides used with permission from Laura Berk

2. Copyright © Allyn & Bacon 2008 Body Growth Gain 50% in height from birth to age 1; 75% by age 2 Grow in spurts Gain “baby fat” until about 9 months, then get slimmer Girls slightly shorter and lighter than boys

3. Copyright © Allyn & Bacon 2008 Growth Trends Cephalocaudal “Head to Tail” Lower part of body grows later than the head Proximodistal “Near to far” Extremities grow later than head, chest, and trunk

4. Copyright © Allyn & Bacon 2008 Epiphyses of the Bone

5. Copyright © Allyn & Bacon 2008 The Skull at Birth

6. Copyright © Allyn & Bacon 2008 Neurons and Their Connective Fibers

7. Copyright © Allyn & Bacon 2008 Major Milestones of Brain Development

8. Copyright © Allyn & Bacon 2008 Methods for Measuring Brain Functioning

9. Copyright © Allyn & Bacon 2008 Regions of the Cerebral Cortex

10. Copyright © Allyn & Bacon 2008 Lateralization and Plasticity of the Cerebral Cortex The left and right hemispheres of the brain control different functions. Specialization of the two hemispheres is called lateralization. –Left hemisphere: best at processing information in a sequential, analytic way. –Right hemisphere: best at processing information in a holistic, integrative manner. In a highly plastic cerebral cortex, many areas are not yet committed to one function, consequently, the cortex has a high capacity for learning.

11. Copyright © Allyn & Bacon 2008 Brain Plasticity Insights In children with injuries to the cerebral cortex that occurred before birth or in the first 6 months of life, language delays persisted to about 3½ years of age. Yet, by age 5, the children caught up in grammatical and vocabulary skills, showing that the undamaged area of the brain—either hemisphere—had taken over the language function. Spatial skills showed more impairment after a brain injury. Researchers speculate that spatial processing is more lateralized at birth. Brain plasticity can occur later in adulthood, for example, in stroke victims.

12. Copyright © Allyn & Bacon 2008 Sensitive Periods in Brain Development Early, extreme sensory deprivation results in permanent brain damage and loss of function. Babies born with cataracts in both eyes who have corrective surgery within 4 to 6 months show rapid improvement in vision. The longer the surgery is postponed, the less complete the recovery of visual skills.

13. Copyright © Allyn & Bacon 2008 Brain Development in Orphanage Children Children adopted from Romanian orphanages before 6 months of age showed dramatic cognitive and physical gains. Those adopted after 6 months, however, showed serious intellectual deficits. The chronic stress of early, deprived orphanage rearing disrupts the brain’s ability to manage stress, with long-term consequences.

14. Copyright © Allyn & Bacon 2008 Relationship of Age at Adoption to Mental Test Scores

15. Copyright © Allyn & Bacon 2008 Sensitive Periods in Brain Development Experience-expectant growth –Ordinary experiences “expected” by brain to grow normally Experience-dependent growth –Specific experience, varies widely

16. Copyright © Allyn & Bacon 2008 Appropriate Stimulation Experience-expectant brain development takes place early and naturally as part of a preschooler’s daily routine. No evidence exists to support a sensitive period in early life when mastering skills that depend on extensive training can occur. In fact, rushing early learning can overwhelm young brains.

17. Copyright © Allyn & Bacon 2008 Sleep Patterns Sleep moves to an adult- like night-day schedule during the first year. Sleep needs decline from 18 to 12 hours a day by age 2. Night wakings often increase between the ages of 1½ and 2 years, and then decline.

18. Copyright © Allyn & Bacon 2008 Cultural Variations in Infant Sleeping Arrangements Cosleeping is the norm for 90% of the world’s population. Cultural values of collectivism versus individualism strongly influence infant sleeping arrangements. Cosleeping is increasing in North America, perhaps because more mothers are breastfeeding.

19. Copyright © Allyn & Bacon 2008 Influences on Early Growth HeredityNutrition –Breast v. Bottle Feeding –Malnutrition Emotional Well-Being –Problems Can Cause Failure to Thrive

20. Copyright © Allyn & Bacon 2008 Benefits of Breastfeeding Correct fat-protein balance Nutritionally complete More digestible Better growth Disease protection Better jaw and tooth development Easier transition to solid food

21. Copyright © Allyn & Bacon 2008 Are Chubby Babies At Risk for Later Obesity? Recent research shows that there is a relationship between rapid weight gain in infancy and later obesity. What to do? –Breastfeed for six months. –Avoid foods loaded with sugar, salt, and saturated fats. –Promote physical exercise. –Limit TV viewing time.

22. Copyright © Allyn & Bacon 2008 Malnutrition TypesMarasmusKwashiorkor Iron-deficiency anemia Food insecurity Consequences Physical symptoms Growth and weight problems Poor motor development Learning, attention problems Passivity, irritability, anxiety

23. Copyright © Allyn & Bacon 2008 Nonorganic Failure to Thrive The baby is offered enough food and has no serious illness, but still has a wasted body and is withdrawn and apathetic. Family circumstances surrounding failure to thrive often help explain the problem. When treated early, by helping the parents or placing the baby in a caring foster home, failure- to-thrive infants show quick catch-up growth. Left untreated, most will remain small and have lasting difficulties.

24. Copyright © Allyn & Bacon 2008 The Steps of Classical Conditioning

25. Copyright © Allyn & Bacon 2008 Operant Conditioning Terms Reinforcer Increases probability of behavior occurring again Presenting desirable stimulus Removing unpleasant stimulus Punishment Reduces probability of behavior occurring again Presenting unpleasant stimulus Removing desirable stimulus

26. Copyright © Allyn & Bacon 2008 Using Habituation to Study Infants

27. Copyright © Allyn & Bacon 2008 Imitation Imitation is a powerful method of learning. It is more difficult to induce in babies 2 to 3 months old than right after birth. Andrew Meltzoff: newborns imitate as much as older children and adults do. Mirror neurons enable us to observe another person’s behavior while simulating that behavior in our own brain. Meltzoff’s theory of newborn imitation as a voluntary capacity is controversial.

28. Copyright © Allyn & Bacon 2008 The Sequence of Motor Development Gross motor development –crawling, standing, walking Fine motor development –reaching and grasping

29. Copyright © Allyn & Bacon 2008 Gross and Motor Development in the First Two Years

30. Copyright © Allyn & Bacon 2008 Motor Skills as Dynamic Systems Increasingly complex systems of action with each skill 4 factors in each new skill: 1.CNS development 2.Body’s movement capacity 3.Child’s goals 4.Environmental supports

31. Copyright © Allyn & Bacon 2008 Steps in Reaching and Grasping PrereachingReaching –With two hands, then one Ulnar Grasp –Adjust grip to object –Move objects from hand to hand Pincer Grasp

32. Copyright © Allyn & Bacon 2008 Keeping Infants and Toddlers Safe Provide safe toys Child-proof all rooms Continuously monitor the infant or toddler Use a car seat, following government regulations Report any unsafe toys and equipment

33. Copyright © Allyn & Bacon 2008 Bowel and Bladder Control Toilet training is best delayed until the months following the second birthday. Effective training techniques include: –establishing regular toileting routines –using gentle encouragement –praising children for their effort

34. Copyright © Allyn & Bacon 2008 Developments in Hearing 4 – 7 months Sense of musical phrasing 6- 8 months “Screen out” sounds from non- native languages 7 – 9 months Divide the speech stream into word-like units 10 months Can detect words that start with weak syllables

35. Copyright © Allyn & Bacon 2008 Improvements in Vision Brain development helps infants reach adult levels of vision skills: 2–4 months: focus and color vision 6 months: acuity, scanning & tracking 6–7 months: depth perception

36. Copyright © Allyn & Bacon 2008 Steps in Depth Perception Birth – 1 month Sensitivity to motion cues. 2 – 3 months Sensitivity to binocular cues. 6 –7 months Sensitivity to pictorial cues. Wariness of heights.

37. Copyright © Allyn & Bacon 2008 Steps in Pattern Perception 3 weeks Poor contrast sensitivity. Prefer large simple patterns. 2 months Can detect fine-grained detail. Prefer complex patterns. 4 months Can detect patterns even if boundaries are not really present. 12 months Can detect objects if two-thirds of drawing is missing.

38. Copyright © Allyn & Bacon 2008 Appearance of Checkerboards to Very Young Infants

39. Copyright © Allyn & Bacon 2008 Subjective Boundaries in Visual Patterns

40. Copyright © Allyn & Bacon 2008 Stimuli for Studying Infants’ Facial Perception

41. Copyright © Allyn & Bacon 2008 Testing Infants’ Ability to Perceive Object Unity

42. Copyright © Allyn & Bacon 2008 Differentiation Theory of Infant Perception Infants actively search for invariant, unchanging features of the environment. –Borders of stimuli, faces They note stable relationships between features. –Complex visual patterns, intermodal relationships Perception gets more and more sensitive— differentiation Acting on the environment helps this process— affordances