Puberty
1. Puberty refers to the various changes that transform a child’s body into an adult one. A sequence of biochemical signals from the hypothalamus to the pituitary gland to the adrenal glands (the HPA axis) increases production of testosterone, estrogen, and various other hormones, which in turn causes the body to develop.
2. Sexual characteristics differentiate males from females at adolescence, not only in reproductive potential, but also in body shape, breasts, voice, body hair, and so on.
3. Puberty most often begins between ages 10 and 13. Genes, gender, body fat, and family stress all contribute to this variation in timing, with girls generally beginning puberty before boys.
4. Adolescents who reach puberty earlier or later than their friends experience additional stresses. Generally (depending on culture, community, and cohort), early-
5. The growth spurt is an acceleration of growth in every part of the body. Peak weight usually precedes peak height, which is then followed by peak muscle growth.
6. Hormones regulate daily and seasonal body rhythms. In adolescence, these may result in sleep deprivation because high schools open early and the natural circadian rhythm keeps teenagers wide awake at night.
Nutrition
7. Many adolescents are very concerned about body image, especially how they think they look to other adolescents. They may diet irrationally instead of eating a balanced diet, which can often result in calcium and iron deficiency.
8. Although anorexia and bulimia are often not diagnosed until early adulthood, their precursors are evident during puberty. The origins are genetic and familial as well as cultural.
Thinking, Fast and Slow
9. Various parts of the brain mature during puberty and in the following decade. The regions dedicated to emotional arousal (including the limbic system) mature before those that regulate and rationalize emotion (the prefrontal cortex). Consequently, many adolescents are quick to react, take risks, and learn.
10. Cognition in early adolescence may be egocentric, a kind of self-
11. Formal operational thought is Piaget’s term for the last of his four periods of cognitive development, in which adolescents are no longer earthbound and concrete in their thinking. They prefer to speculate instead of focusing on reality. They develop hypotheses and explore, using deductive reasoning.
12. Intuitive thinking also becomes stronger during adolescence. Few teenagers always use logic, although they are capable of doing so.
Teaching and Learning
13. Secondary education—
14. In middle school, many students tend to be bored, difficult to teach, and hurtful to one another. One reason may be that middle schools are not structured to accommodate egocentrism or intuitive thinking.
15. Cyberbulling and many forms of psychopathology increase during school transitions, which are particularly difficult in adolescence, when young people must also adjust to biological and family changes.
16. The PISA, an international test for high school students, is designed to measure the cognitive abilities that students will need in adult life.