Chapter 4 Physical Development in Infancy and Toddlerhood.

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, some ethnic differences

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. 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

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Growth During First Two Years Figure 5.1

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Epiphyses of the Bone Figure 5.2

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. The Skull at Birth Figure 5.3

Brain Development  Human brain has 100 to 200 billion neurons that store/transmit information  At birth, brain closest to adult size than any other physical structure 75%) Figure 5.4

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Major Milestones of Brain Development Figure 5.5

Regions of the Cerebral Cortex Figure 5.8

Lateralization and Plasticity of the Cerebral Cortex Specialization of the left and right hemispheres of the brain is called lateralization. Left hemisphere: specializes in language; positive emotion Left hemisphere: specializes in language; positive emotion Right hemisphere: non-speech sounds, negative emotion; spatial Right hemisphere: non-speech sounds, negative emotion; spatial Highly plastic cerebral cortex, many areas are not yet committed to one function

Brain Plasticity Insights  Injuries to the cerebral cortex occurring before birth or in the first 6 months, language delays persisted to about 3½ years of age.  By age 5, the children caught up in grammatical and vocabulary skills; undamaged area of the brain—either hemisphere—take over the language function.  Spatial skills showed more impairment after a brain injury, likely because spatial processing is more lateralized at birth.  Brain plasticity can occur later in adulthood (e.g., in stroke victims).

Brain Development in Orphanage Children Figure 5.9

Appropriate Stimulation Experience-expectant growth Experience-dependent growth. © Andres Rodriguez | Dreamstime.comAndres RodriguezDreamstime.com

Influences on Early Growth HeredityNutrition  Breast v. bottle feeding  Malnutrition Emotional well-being  Problems can cause failure to thrive © Dean Mitchell | Dreamstime.comDean MitchellDreamstime.com

Benefits of Breastfeeding  Correct fat – protein balance  Nutritionally complete  Promotes healthy growth patterns  Disease protection  Better jaw and tooth development  Ensures digestibility  Easier transition to solid food

Emotional Well-Being Affection is as vital as food for healthy physical growth. Non-organic failure to thrive: weight, height, and head circumference are substantially below age- related growth norms. Infants are withdrawn and apathetic. Infants are withdrawn and apathetic. Often a result of disturbed parent–child relationship Often a result of disturbed parent–child relationship Unhappy marriage or parental psychological disturbance may be at fault. Unhappy marriage or parental psychological disturbance may be at fault. May cause lasting cognitive and emotional difficulties May cause lasting cognitive and emotional difficulties

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. The Sequence of Motor Development Gross-motor development Crawling, standing, walking Crawling, standing, walking Fine-motor development Reaching and grasping Reaching and grasping © Felix Mizioznikov | Dreamstime.comFelix MizioznikovDreamstime.com

Gross- and Fine-Motor Development in the First Two Years

Motor Skills as Dynamic Systems Increasingly complex systems of action with each skill Four factors in each new skill: © Alberalber | Dreamstime.comAlberalberDreamstime.com

Cultural Variations in Motor Development Home environments and infant rearing practices affect motor development. Some cultures discourage rapid motor progress. Some cultures discourage rapid motor progress. Kipsigis of Kenya and the West Indians of Jamaica teach early motor skills. Kipsigis of Kenya and the West Indians of Jamaica teach early motor skills. Western parents consider crawling and “tummy time” essential, but not all cultures do. Western parents consider crawling and “tummy time” essential, but not all cultures do.

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Milestones of Reaching Figure 5.14

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. The Steps of Classical Conditioning Figure 5.10

Operant Conditioning Terms Reinforcer Increases probability of behavior occurring again Presenting desirable stimulus Presenting desirable stimulus Removing unpleasant stimulus Removing unpleasant stimulus Punishment Reduces probability of behavior occurring again Presenting unpleasant stimulus Presenting unpleasant stimulus Removing desirable stimulus Removing desirable stimulus

Using Habituation to Study Infants Figure 5.11

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.  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.

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Imitation by Human and Chimpanzee Newborns Figure 5.12

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Developments in Hearing p. 140 starts 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

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Improvements in Vision Brain development helps infants reach adult levels of vision skills. 2–4 months: focus and color vision 6 months: acuity, scanning, and tracking 6–7 months: depth perception © Mitja Mladkovic | Dreamstime.comMitja MladkovicDreamstime.com

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. 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 boundaries are not really present 12 months  Can detect objects if two-thirds of drawing is missing of drawing is missing

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Appearance of Checkerboards to Very Young Infants Figure 5.17

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Subjective Boundaries in Visual Patterns Figure 5.18

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Early Face Perception Figure 5.19

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Testing Infants’ Ability to Perceive Object Unity Figure 5.20

Copyright © 2012 Pearson Education, Inc. All Rights Reserved. Acting on the Environment Plays a Major Role in Perceptual Differentiation Figure 5.21