Chapter 11 Ages of children in middle childhood: 6-11. Growth and health of children in middle childhood: Middle childhood is a time of steady growth and few serious illnesses. Increasing independence and self-care allow most school-age children to be relatively happy and competent.Advances in medical care, including effective immunization, have reduced childhood sickness and death. Physical activity aids health and joy in many ways. However, current social and environmental conditions make informal neighborhood play rare and school physical education less prevalent.Changes in self-esteem: Self-Esteem gets worse as they get olderDevelopment of PrejudiceDefinitions of BMI, overweight and obesity: Body Mass Index (BMI), Overweight: having a BMI above the 85thpercentile, Obesity: having a BMI above the 95thpercentile. Contributors to obesity, asthma: Childhood overweight correlates with asthma, high blood pressure, and elevated cholesterol. School achievement decreases, self-esteem falls, and loneliness rises. If obese children stay heavy, the become adults who are less likely to marry, attend college, or find work that reflects their ability. Childhood obesity is a worldwide epidemic. Although genes are part of the problem, too little exercise and the greater availability of unhealthy foods are the main reasons today’s youth are heavier than their counterparts of 50 years ago. Parents and policies share the blame.Asthma preventions: The incidence of asthma is increasing overall, with notable ethnic differences. The origins of asthma are genetic; the triggers are specific environmental allergens. Preventive measures include longer breast-feeding, increased outdoor play, and less air pollution, particularly from cars.Brain development: Brain development continues during middle childhood, enhancing every aspect of development. Notable are advances in reaction time and automatization, allowing faster and better coordination of many parts of the brain.Aptitude tests: IQ tests quantify intellectual aptitude. Most such tests emphasize language and logic ability and predictschool achievement. IQ scores sometimes change over time, partly because of maturation but primarily because of experience.Achievement tests: Achievement tests measure accomplishment, often in specific academic areas. Aptitude and achievement are correlated, both for individuals and for nations, and have risen in the past decades.