©2001 Allyn & Bacon
|
| |
| |
|
|
Chapter 5: Physical Development in Infancy and Toddlerhood
Body size increases dramatically during the first 2 years of life, following organized patterns of growth. Fat increases faster than muscle, and the skull expands rapidly to accommodate the rapidly growing brain. Neurons form intricate connections and their fibers myelinate, causing a rapid increase in brain weight. Already, the two hemispheres of the cortex have begun to specialize, although the brain retains considerable plasticity during the first few years. In addition, specific sensitive periods in brain development are now recognized, when the brain must receive appropriate stimulation for it to reach its full potential.
A variety of factors affect early physical growth. Heredity contributes to height, weight, and rate of physical maturation. Nutrition is essential for rapidly growing babies, and breast milk is especially suited to meet their needs. Malnutrition during the early years can result in permanent stunting of physical growth and of brain development. Affection and stimulation are also essential for healthy physical growth.
Infants are marvelously equipped to learn immediately after birth. Classical conditioning, operant conditioning, habituation-dishabituation, and imitation are important early learning capacities that assist infants in finding out about their physical and social worlds.
Although motor development follows the same organized sequences as physical growth, it does not follow a fixed maturational timetable. According to dynamic systems theory, previously learned skills are combined in increasingly complex ways to result in new abilities. Central nervous system development, movement possibilities of the body, the task the child has in mind, and environmental supports combine to influence the development of motor skills.
Hearing and vision undergo major advances during the first 2 years as infants organize stimuli into complex patterns, improve their perception of depth and objects, and combine information across sensory modalities. The Gibsons' differentiation theory helps us understand the course of perceptual development.
©2001 Allyn & Bacon |