Chapter 5: Physical Development in Infants and Toddlers MODULES 5.1 Healthy Growth 5.2 The Developing Nervous System 5.3 Motor Development 5.4 Sensory and Perceptual Processes Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Module 5.1 Healthy Growth LEARNING OBJECTIVES Outline the important features of physical growth in infants and toddlers and how they vary from child to child. Describe how heredity, hormones, and nutrition contribute to physical growth. Summarize how malnutrition, disease, and accidents affect infants’ and toddlers’ physical growth. Copyright © 2009 Pearson Education Canada

Features of Human Growth Follows the cephalocaudal principle. Muscles become longer and thicker. During the first year, a layer of fat is added. Cartilage is replaced by bone. Copyright © 2009 Pearson Education Canada

Variations on the Average Profile Secular Growth Trends: generational changes in physical development. Average and normal are not the same. Average Height and Weight Copyright © 2009 Pearson Education Canada

Mechanisms of Physical Growth Heredity influences adult height. The pituitary gland secretes growth hormone. Nutrition is particularly important during infancy when growth is rapid. At 2 years, growth slows and kids become “picky” eaters. Copyright © 2009 Pearson Education Canada

Challenges to Healthy Growth Malnutrition is especially damaging in infancy. Malnutrition needs to be treated with adequate diet and parent education. Many diseases that kill young children are preventable with vaccines, improved health care, and changing habits. After the first year of life children are more likely to die from accidents than from any other single cause. Copyright © 2009 Pearson Education Canada

Module 5.2 The Developing Nervous System LEARNING OBJECTIVES Be able to draw a nerve cell and identify its major parts. Discuss how the brain is organized. Identify when the brain is formed during prenatal development and when different regions of the brain begin to function. Copyright © 2009 Pearson Education Canada

Organization of the Mature Brain Neuron: basic unit of nervous system, specializes in transmitting information. Synapse: a gap or space between neurons. Cerebral hemispheres: right and left halves of the cortex. Frontal cortex: area of the cortex that controls personality and the ability to carry out plans. Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada The Developing Brain Brain originates in neural plate. Brain regions specialize early (e.g., left hemisphere for verbal functioning; frontal cortex for emotion). “Flexible” or neuroplasticity of brain organization shown by children who recover from brain damage. Copyright © 2009 Pearson Education Canada

Module 5.3 Motor Development LEARNING OBJECTIVES State how reflexes help infants interact with the world. Detail the component skills involved in learning to walk, and at what age infants typically master them. Describe how infants learn to coordinate the use of their hands and why most children begin to prefer to use one hand. Discuss how maturation and experience influence children’s acquisition of motor skills. Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada The Infant’s Reflexes Newborns’ reflexes prepare them to interact with the world. Some reflexes are important to survival (e.g., rooting and sucking). Some protect the newborn (e.g., blink and withdrawal). Some are foundations for later motor behaviour (e.g., stepping reflex). Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Locomotion Dynamic Systems Theory: motor development involves many distinct skills. Differentiation and integration of component skills (posture and balance, stepping, perceptual skill) is necessary. Source: Based on Shirley, 1931, and Bayley, 1969 Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Fine Motor Skills Maturation, Experience, and Motor Skill Reaching and grasping becomes more coordinated throughout infancy. Toddlers prefer to use one hand and this preference becomes stronger during the preschool years. Maturation is important: Studies of Hopi infants. Experience matters, too: African infants and training studies. Copyright © 2009 Pearson Education Canada

Module 5.4 Sensory and Perceptual Processes LEARNING OBJECTIVES Describe the sensory abilities of the newborn. State how well infants hear and how they use sounds to understand the world. State how accurate infants’ vision is and whether they perceive colour and depth. Summarize how infants integrate information from different senses. Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Hearing Smell, Taste, and Touch Infants hear well, though not quite as accurately as adults. -Auditory threshold: the quietest sound that a person can hear. Infants’ can distinguish different sounds and use sounds to judge the distance and location of objects. Even newborns can smell, taste, and feel. These skills are useful in recognizing their mothers and in feeding. Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Seeing Acuity is 20/400 at birth but improves rapidly. Infants perceive colours by 3 or 4 months. Infants master perceptual constancies early. Many cues are used to infer depth. Edges & motion are used to perceive objects. Wavelength of Light Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Infants’ Scanning of Faces Perception of Objects Face-like Stimuli Use of Motion to Perceive Objects Copyright © 2009 Pearson Education Canada

Integrating Sensory Information By 1 month, can integrate sight and touch. By 4 months, can integrate sight and sound. 4- and 7-month-olds can match facial appearance (boy or man) with sound of voice. Copyright © 2009 Pearson Education Canada

Time Spent Looking at Videos Infant Watching Videos Copyright © 2009 Pearson Education Canada

Copyright © 2009 Pearson Education Canada Conclusions Nutrition is important for physical growth in children. The brain and nervous system develop throughout childhood through synaptic pruning and myelination. Infants are born with many reflexes while their locomotor skills progress through a series of milestones and reflect maturation and experience. Soon after birth, infants coordinate information from different senses (vision, hearing, smell, touch). They recognize by sight an object they have touched before and integrate what they hear with what they see. Copyright © 2009 Pearson Education Canada