Thursday, October 22, 201512:39 AMChapter 8: Biosocial Development in 2-6 year oldsI. Body Changes 1. Between 2 and 6 years of age, children -Grow almost 3 inches (about 7 centimeters) -Gain about 4.5 pounds (2 kilograms) per year 2. Picky at age 3-Want certain routines and rituals-Strong preferences (food, clothes, things done in an order)3. By age 6, the average child in a developed nation -Weighs between 40 and 50 pounds (between 18 and 22 kilograms) -Measures at least 3 1/2 feet (more than 100 centimeters)4. Because growth is slower during early childhood, children need fewer calories per pound of body weight; consequently, their appetites are smaller, a fact that causes many parents some concern, though normal. An additional common problem is the phenomenon called “just right” or “just so,” in which children are rigid about their daily routines, including their food preferences and rituals.II. Brain Development (5 questions)1. During childhood, the brain develops faster than any other part of the body. This maturation underlies children’s rapidly expanding cognitive and motor abilities. -By age 2, most pruning of the brain’s dendrites has occurred. -Age 2 - brain weighs 75% of its adult weight-Age 6, the brain reaches 90% of its adult weight. 2. The continued proliferation of communication pathways, along with myelination (KNOW TERM)-A process that insulates the axons of neurons and speeds transmission of neural impulses, accounts for part of this rapid brain growth-Myelination enables the child to think, process, respond much quicker than the toddler can-Gradual increase, more and more myelin wraps around the axon throughout childhood-Ex. Over and over again, allows each attempt to take less time3. The corpus callosum (KNOW BRAIN STRUCTURE AND FUNCTION)-The long, thick band of nerve fibers that connects the two sides (left and right hemispheres) of the brain, grows and myelinates rapidly during early childhood.-It allows children to better coordinate functions that involve both sides of the brain and body, which are not identical.-Allows communication between them4. The lateralization (KNOW TERM)-The specialization of the two sides of the body and brain (prompted by genes, prenatal hormones, and early experiences). This process is apparent in handedness and in the feet, eyes, ears, and the brain itself. -One side dominant for each activity-Ex. Throughout the world, societies are organized to favor right-handedness. Experts advise against trying to switch a child’s handedness.-The left hemisphere of the brain controls the right side of the body and contains areas dedicated to logical reasoning, detailed analysis, and the basics of language. -The right hemisphere controls the left side of the body and contains brain areas dedicated to generalized emotional and creative impulses.5. The prefrontal cortex (KNOW STRUCTURE AND FUNCTION)-The final part of the brain to reach maturity, which specializes in the executive functions of planning, prioritizing, and reflection. -Development of this brain area is limited in infancy, not completed until emerging adulthood. -Between ages 2 and 6 - neurological increases are notable in areas of cortex, where planning thinking, social awareness, language occur-Maturation of prefrontal cortex = more control-Sleep becomes regular-Emotions more nuanced and responsive-Temper tantrums decrease, subside-Uncontrollable laughter and tears are less common-The prefrontal cortex assists in impulse control and emotional regulation. Two signs of an undeveloped prefrontal cortex are impulsiveness and perseveration, the tendency to stick to a thought or action for a long time. -Maturation of prefrontal cortex gradually facilitates focused attention and curbed impulsiveness-Before this, many young children jump from task to task, cannot stay quiet-Others act oppositely, (perseveration) - stick to a thought or action, unable to quit6. The brain’s limbic system (emotional brain) plays a crucial role in the expression and regulation of emotions.-Within this system is the amygdala, which registers emotions, both positive and negative, especially fear and anxiety. -Next to this area is the hippocampus (brain structure and function), which is a central processor center of memory, especially for locations, important for memory. -Limbic structure can become hypersensitive-Ex. Children watching parent's emotions becoming fearful, happens often, children remembers (hippocampus), children become fearful-The hypothalamus (brain structure and function), responds to amygdala and hippocampus, produces cortisol and other hormones that activate parts of the brain and body. 7. In the hormonal feedback loop called the hypothalamus-pituitary-adrenal axis (HPA), the hippocampus and the amygdala stimulate the hypothalamus to produce the hormone CRH, which signals the pituitary gland to produce ACTH, which then triggers the production of glucocorticoids (CORT) by the adrenal glands.8. Excessive cortisol, the primary stress hormone, may destroy part of the brain’s hippocampus.Excessive stress hormones in early childhood may permanently damage (brain damage resulting from stress hormones) the limbic system and influence emotional responses throughout life. -Moderate stress is beneficial - emotionally arousing experiences-Early traumatic or stressful events - increased risk with flooded cortisol in brain and destroys part of hippocampus-Ex. Due to maltreatment, permanent emotional responses, learning and memory deficits, major depression, PTSD, ADHDIII. Improved Motor Skills (Fine and gross motor skills - Know what they can do)1. Maturation of the prefrontal cortex improves impulse control, while myelination of the corpus callosum and lateralization of the brain permit better physical coordination.2. Gross motor skills (large body movements such as running, climbing, jumping, and throwing)improve dramatically between ages 2 and 6. According to sociocultural theory, children learnthese skills best from other children.3. Fine motor skills (small body movements such as pouring without spilling and using a knife and fork) are much harder for preschoolers to master. Fine motor skills typically mature about 6 months earlier in girls.-Difficult to master-Involve small hand and finger movements-Involve both sides of brain4. The difficulties children have with fine motor skills are attributable to several factors: an immature corpus callosum (many fine motor skills