Part Introduction

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adolescence

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A century ago, puberty began at age 15 or so. Soon after that age, most girls married and most boys found work. It is said that adolescence begins with biology and ends with culture. If so, then a hundred years ago, adolescence lasted a few months. Now adolescence lasts many years. Puberty starts before the teen years, and adult responsibilities are often postponed until emerging adulthood or later.

In the next three chapters (covering ages 11 to 18), we begin with biology (this chapter), consider cognition (Chapter 15), and then discuss culture (Chapter 16). Adolescence attracts extremes, arousing the highest hopes and the worst fears of parents, teachers, police officers, social workers, and children themselves. Patterns and events can catapult a teenager to destruction or celebration. Understanding this phase of development is the first step toward ensuring that the teenagers you know, and the millions you never met, experience a fulfilling, not devastating, adolescence.