Adolescence

Encyclopedia of Childhood and Adolescence by Laurence Steinberg, Ph.D. Temple University

Adolescence is a border between adulthood and childhood, and as such it has a richness and diversity unmatched by any other life stage. ... Adolescents are travelers, far from home with no native land, neither children nor adults. They are jet-setters who fly from one country to another with amazing speed. Sometimes they are four years old, an hour later they are twenty-five. They don't really fit anywhere. There's a yearning for place, a search for solid ground.

--A description of adolescents by Mary Pipher in her 1994 book, Reviving Ophelia.

In the study of child development, adolescence refers to the second decade of the life span, roughly from ages 10 to 20. The word adolescence is Latin in origin, derived from the verb adolescere, which means "to grow into adulthood." In all societies, adolescence is a time of growing up, of moving from the immaturity of childhood into the maturity of adulthood. Population projections indicate that the percent of the U.S. population between the ages of 14 and 17 will peak around the year 2005.

Population projections

Year	Population, ages 14-17 (1,000)	Percent of population ages 14-17
2000	15,752	5.7%
2005	16,986	5.9%
2010	16,894	5.7%
2025	17,872	5.3%
2050	21,206	5.4%

There is no single event or boundary line that denotes the end of childhood or the beginning of adolescence. Rather, experts think of the passage from childhood into and through adolescence as composed of a set of transitions that unfold gradually and that touch upon many aspects of the individual's behavior, development, and relationships. These transitions are biological, cognitive, social, and emotional.

Puberty

The biological transition of adolescence, or puberty , is perhaps the most salient sign that adolescence has begun. Technically, puberty refers to the period during which an individual becomes capable of sexual reproduction. More broadly speaking, however, puberty is used as a collective term to refer to all the physical changes that occur in the growing girl or boy as the individual passes from childhood into adulthood.

The timing of physical maturationvaries widely. In the United States today, menarche, the first menstrual period, typically occurs around age 12, although some youngsters start puberty when they are only eight or nine, others when they are well into their teens. The duration of puberty also varies greatly: eighteen months to six years in girls and two to five years in boys.

The physical changes of puberty are triggered by hormones , chemical substances in the body that act on specific organs and tissues. In boys a major change is the increased production of testosterone, a male sex hormone, while girls experience increased production of the female hormone estrogen. In both sexes, a rise in growth hormone produces the adolescent growth spurt, the pronounced increase in height and weight that marks the first half of puberty.

Perhaps the most dramatic changes of puberty involve sexuality. Internally, through the development of primary sexual characteristics, adolescents become capable of sexual reproduction. Externally, as secondary sexual characteristics appear, girls and boys begin to look like mature women and men. In boys primary and secondary sexual characteristics usually emerge in a predictable order, with rapid growth of the testes and scrotum, accompanied by the appearance of pubic hair. About a year later, when the growth spurt begins, the penis also grows larger, and pubic hair becomes coarser, thicker, and darker. Later still comes the growth of facial and body hair, and a gradual lowering of the voice. Around mid-adolescence internal changes begin making a boy capable of producing and ejaculating sperm.

In girls, sexual characteristics develop in a less regular sequence. Usually, the first sign of puberty is a slight elevation of the breasts, but sometimes this is preceded by the appearance of pubic hair. Pubic hair changes from sparse and downy to denser and coarser. Concurrent with these changes is further breast development. In teenage girls, internal sexual changes include maturation of the uterus, vagina, and other parts of the reproductive system. Menarche, the first menstrual period, happens relatively late, not at the start of puberty as many people believe. Regular ovulation and the ability to carry a baby to full term usually follow menarche by several years.

For many years, psychologists believed that puberty was stressful for young people. We now know that any difficulties associated with adjusting to puberty are minimized if adolescents know what changes to expect and have positive attitudes toward them. Although the immediate impact of puberty on the adolescent's self-image and mood may be very modest, the timing of physical maturation does affect the teen's social and emotional development in important ways. Early-maturing boys tend to be more popular, to have more positive self-conceptions, and to be more self-assured than their later-maturing peers, whereas early-maturing girls may feel awkward and self-conscious.

Cognitive transition

A second element of the passage through adolescence is a cognitive transition. Compared to children, adolescents think in ways that are more advanced, more efficient, and generally more complex. This can be seen in five ways.

First, during adolescence individuals become better able than children to think about what is possible, instead of limiting their thought to what is real. Whereas children's thinking is oriented to the here and now--that is, to things and events that they can observe directly, adolescents are able to consider what they observe against a backdrop of what is possible--they can think hypothetically.

Second, during the passage into adolescence, individuals become better able to think about abstract ideas. For example, adolescents find it easier than children to comprehend the sorts of higher-order, abstract logic inherent in puns, proverbs, metaphors, and analogies. The adolescent's greater facility with abstract thinking also permits the application of advanced reasoning and logical processes to social and ideological matters. This is clearly seen in the adolescent's increased facility and interest in thinking about interpersonal relationships, politics, philosophy, religion, and morality--topics that involve such abstract concepts as friendship, faith, democracy, fairness, and honesty.