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Puberty, Cognitive transition, Emotional transition, Social transition

Sometimes referred to as teenage years, youth, or puberty, adolescence covers the period from roughly age 10 to 20 in a child's development.

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

Alfred Adler (Archive Photos, Inc. Reproduced with permission.)

that the percent of the U.S. population between the ages of 14 and 17 will peak around the year 2005.

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.


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 maturation varies 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.

Third, during adolescence individuals begin thinking more often about the process of thinking itself, or metacognition. As a result, adolescents may display increased introspection and self-consciousness. Although improvements in metacognitive abilities provide important intellectual advantages, one potentially negative byproduct of these advances is the tendency for adolescents to develop a sort of egocentrism, or intense preoccupation with the self. Acute adolescent egocentrism sometimes leads teenagers to believe that others are constantly watching and evaluating them, much as an audience glues its attention to an actor on a stage. Psychologists refer to this as the imaginary audience.

A fourth change in cognition is that thinking tends to become multidimensional, rather than limited to a single issue. Whereas children tend to think about things one aspect at a time, adolescents can see things through more complicated lenses. Adolescents describe themselves and others in more differentiated and complicated terms and find it easier to look at problems from multiple perspectives. Being able to understand that people's personalities are not one-sided, or that social situations can have different interpretations, depending on one's point of view, permits the adolescent to have far more sophisticated—and complicated—relationships with other people.

Finally, adolescents are more likely than children to see things as relative, rather than absolute. Children tend to see things in absolute terms—in black and white. Adolescents, in contrast, tend to see things as relative. They are more likely to question others' assertions and less likely to accept "facts" as absolute truths. This increase in relativism can be particularly exasperating to parents, who may feel that their adolescent children question everything just for the sake of argument. Difficulties often arise, for example, when adolescents begin seeing their parents' values as excessively relative.

Emotional transition

In addition to being a time of biological and cognitive change, adolescence is also a period of emotional transition and, in particular, changes in the way individuals view themselves and in their capacity to function independently.

During adolescence, important shifts occur in the way individuals think about and characterize themselves—that is, in their self-conceptions. As individuals mature intellectually and undergo the sorts of cognitive changes described earlier, they come to perceive themselves in more sophisticated and differentiated ways. Compared with children, who tend to describe themselves in relatively simple, concrete terms, adolescents are more likely to employ complex, abstract, and psychological self-characterizations. As individuals' self-conceptions become more abstract and as they become more able to see themselves in psychological terms, they become more interested in understanding their own personalities and why they behave the way they do.

Conventional wisdom holds that adolescents have low self-esteem —that they are more insecure and self-critical than children or adults—but most research indicates otherwise. Although teenagers' feelings about themselves may fluctuate, especially during early adolescence, their self-esteem remains fairly stable from about age 13 on. If anything, self-esteem increases over the course of middle and late adolescence. Most researchers today believe that self-esteem is multidimensional, and that young people evaluate themselves along several different dimensions. As a consequence, it is possible for an adolescent to have high self-esteem when it comes to his academic abilities, low self-esteem when it comes to athletics, and moderate self-esteem when it comes to his physical appearance.

One theorist whose work has been very influential on our understanding of adolescents' self-conceptions is Erik Erikson, who theorized that the establishment of a coherent sense of identity is the chief psychosocial task of adolescence. Erikson believed that the complications inherent

During adolescence, most American girls experiment with make-up. (Photo by Robert J. Huffman. Field Mark Publications. Reproduced with permission.)

in identity development in modern society have created the need for a psychosocial moratorium—a time-out during adolescence from the sorts of excessive responsibilities and obligations that might restrict the young person's pursuit of self-discovery. During the psychosocial moratorium, the adolescent can experiment with different roles and identities, in a context that permits and encourages this sort of exploration. The experimentation involves trying on different personalities and ways of behaving. Sometimes, parents describe their teenage children as going through "phases." Much of this behavior is actually experimentation with roles and personalities.

For most adolescents, establishing a sense of autonomy, or independence, is as important a part of the emotional transition out of childhood as is establishing a sense of identity. During adolescence, there is a movement away from the dependency typical of childhood toward the autonomy typical of adulthood. One can see this in several ways.

First, older adolescents do not generally rush to their parents whenever they are upset, worried, or in need of assistance. Second, they do not see their parents as all knowing or all-powerful. Third, adolescents often have a great deal of emotional energy wrapped up in relationships outside the family; in fact, they may feel more attached to a boyfriend or a girlfriend than to their parents. And finally, older adolescents are able to see and interact with their parents as people—not just as their parents. Many parents find, for example, that they can confide in their adolescent children, something that was not possible when their children were younger, or that their adolescent children can easily sympathize with them when they have had a hard day at work.

Some theorists have suggested that the development of independence be looked at in terms of the adolescent's developing sense of individuation. The process of individuation, which begins during infancy and continues well into late adolescence, involves a gradual, progressive sharpening of one's sense of self as autonomous, as competent, and as separate from one's parents. Individuation, therefore, has a great deal to do with the development of a sense of identity, in that it involves changes in how we come to see and feel about ourselves.

The process of individuation does not necessarily involve stress and internal turmoil. Rather, individuation entails relinquishing childish dependencies on parents in favor of more mature, more responsible, and less dependent relationships. Adolescents who have been successful in establishing a sense of individuation can accept responsibility for their choices and actions instead of looking to their parents to do it for them.

Being independent means more than merely feeling independent, of course. It also means being able to make your own decisions and to select a sensible course of action by yourself. This is an especially important capability in contemporary society, where many adolescents are forced to become independent decision makers at an early age. In general, researchers find that decision-making abilities improve over the course of the adolescent years, with gains continuing well into the later years of high school.

Many parents wonder about the susceptibility of adolescents to peer pressure. In general, studies that contrast parent and peer influences indicate that in some situations, peers' opinions are more influential, while in others, parents' are more influential. Specifically, adolescents are more likely to conform to their peers' opinions when it comes to short-term, day-to-day, and social matters—styles of dress, tastes in music, and choices among leisure activities. This is particularly true during junior high school and the early years of high school. When it comes to long-term questions concerning educational or occupational plans, however, or values, religious beliefs, and ethical issues, teenagers are influenced in a major way by their parents.

Susceptibility to the influence of parents and peers changes with development. In general, during childhood, boys and girls are highly oriented toward their parents and less so toward their peers; peer pressure during the early elementary school years is not especially strong. As they approach adolescence, however, children become somewhat less oriented toward their parents and more oriented toward their peers, and peer pressure begins to escalate. During early adolescence, conformity to parents continues to decline and conformity to peers and peer pressure continues to rise. It is not until middle adolescence, then, that genuine behavioral independence emerges, when conformity to parents as well as peers declines.

Social transition

Accompanying the biological, cognitive, and emotional transitions of adolescence are important changes in the adolescent's social relationships, or the social transition of adolescence. Developmentalists have spent considerable time charting the changes that take place with friends and with family members as the individual moves through the adolescent years.

One of the most noteworthy aspects of the social transition into adolescence is the increase in the amount of time individuals spend with their peers. Although relations with agemates exist well before adolescence, during the teenage years they change in significance and structure. Four specific developments stand out.

First, there is a sharp increase during adolescence in the sheer amount of time individuals spend with their peers and in the relative time they spend in the company of peers versus adults. In the United States, well over half of the typical adolescent's waking hours are spent with peers, as opposed to only 15% with adults—including parents. Second, during adolescence, peer groups function much more often without adult supervision than they do during childhood. Third, during adolescence increasingly more contact with peers is with opposite-sex friends.

Finally, whereas children's peer relationships are limited mainly to pairs of friends and relatively small groups—three or four children at a time, for example— adolescence marks the emergence of larger groups of peers, or crowds. Crowds are large collectives of similarly stereotyped individuals who may or may not spend much time together. In contemporary American high schools, typical crowds are "jocks," "brains," "nerds," "populars," "druggies," and so on. In contrast to cliques, crowds are not settings for adolescents' intimate interactions or friendships, but, instead, serve to locate the adolescent (to himself and to others) within the social structure of the school. As well, the crowds themselves tend to form a sort of social hierarchy or map of the school, and different crowds are seen as having different degrees of status or importance.

The importance of peers during early adolescence coincides with changes in individuals' needs for intimacy. As children begin to share secrets with their friends, a new sense of loyalty and commitment grows, a belief that friends can trust each other. During adolescence, the search for intimacy intensifies, and self-disclosure between best friends becomes an important pastime. Teenagers, especially girls, spend hours discussing their innermost thoughts and feelings, trying to understand one another. The discovery that they tend to think and feel the same as someone else becomes another important basis of friendship.

One of the most important social transitions that takes place in adolescence concerns the emergence of sexual and romantic relationships. In contemporary society, most young people begin dating sometime during early adolescence.

Dating during adolescence can mean a variety of different things, from group activities that bring males and females together (without much actual contact between the sexes); to group dates, in which a group of boys and girls go out jointly (and spend part of the time as couples and part of the time in large groups); to casual dating as couples; and to serious involvement with a steady boyfriend or girlfriend. More adolescents have experience in mixed-sex group activities like parties or dances than dating, and more have experience in dating than in having a serious boyfriend or girlfriend.

Most adolescents' first experience with sex falls into the category of "autoerotic behavior"—sexual behavior that is experienced alone. The most common autoerotic activities reported by adolescents are erotic fantasies and masturbation. By the time most adolescents have reached high school, they have had some experience with sex in the context of a relationship. About half of all American teenagers have had sexual intercourse by the time of high school graduation.

Estimates of the prevalence of sexual intercourse among American adolescents vary considerably from study to study, depending on the nature of the sample surveyed and the year and region in which the study was undertaken. Although regional and ethnic variations make it difficult to generalize about the "average" age at which American adolescents initiate sexual intercourse, national surveys of young people indicate that more adolescents are sexually active at an earlier age today than in the recent past.

For many years, researchers studied the psychological and social characteristics of adolescents who engaged in premarital sex, assuming that sexually active teenagers were more troubled than their peers. This view has been replaced as sexual activity has become more prevalent. Indeed, several recent studies show that sexual activity during adolescence is decidedly not associated with psychological disturbance.

Although it is incorrect to characterize adolescence as a time when the family ceases to be important, or as a time of inherent and inevitable family conflict, early adolescence is a period of significant change and reorganization in family relationships. In most families, there is a movement during adolescence from patterns of influence and interaction that are asymmetrical and unequal to ones in which parents and their adolescent children are on a more equal footing. Family relationships change most around the time of puberty, with increasing conflict between adolescents and their parents—especially between adolescents and their mothers—and closeness between adolescents and their parents diminishing somewhat. Changes in the ways adolescents view family rules and regulations, especially, may contribute to increased disagreement between them and their parents.

Although puberty seems to distance adolescents from their parents, it is not associated with familial "storm and stress," however. Family conflict during this stage is more likely to take the form of bickering over day-to-day issues than outright fighting. Similarly, the diminished closeness is more likely to be manifested in increased privacy on the part of the adolescent and diminished physical affection between teenagers and parents, rather than any serious loss of love or respect between parents and children. Research suggests that this distancing is temporary, though, and that family relationships may become less conflicted and more intimate during late adolescence.

Generally speaking, most young people are able to negotiate the biological, cognitive, emotional, and social transitions of adolescence successfully. Although the mass media bombard us with images of troubled youth, systematic research indicates that the vast majority of individuals move from childhood into and through adolescence without serious difficulty.

Laurence Steinberg, Ph.D.

Further Reading

Feldman, S., and G. Elliott, eds. At the Threshold: The Developing Adolescent. Cambridge: Harvard University Press, 1990.

Pipher, Mary. Reviving Ophelia. New York: Ballantine Books, 1994.

Steinberg, L. Adolescence. 4th ed. New York: McGraw-Hill, 1996.

Steinberg, L., and A. Levine. You and Your Adolescent: A Parent's Guide for Ages 10 to 20. New York: HarperPerennial, 1991.

Additional topics

Psychology EncyclopediaChild Development