Adolescence: Physical, Cognitive, Social, and Emotional Changes

Adolescence is a developmental stage that begins with puberty and ends with the transition to emerging adulthood (young adulthood); the typical age span is from approximately 10 to 20 years. Adolescence has evolved historically, with evidence indicating that this stage is lengthening as individuals start puberty earlier and transition to adulthood later than in the past.

This chapter will outline changes that occur during adolescence in three domains: physical, cognitive, and socioemotional/psychosocial. Physical changes associated with puberty are triggered by hormones. Cognitive changes include improvements in complex and abstract thought, as well as development that happens at different rates in distinct parts of the brain and increases adolescents’ propensity for risky behavior because increases in sensation-seeking and reward motivation precede increases in cognitive control. Within the psychosocial domain, changes in relationships with parents, peers, and romantic partners will be considered. Finally, the chapter summarizes sources of diversity in adolescents’ experiences and development.

Adolescence has frequently been portrayed as a negative stage of life—a period of storm and stress to be survived or endured in professional literature and in the media.^[1] Adolescents are often characterized as impulsive, reckless, and emotionally unstable. This tends to be attributed to “raging hormones” or what is now known as the “teen brain.”

With so many negative images of adolescents, the positive aspects of adolescence can be overlooked.^[2] Most adolescents in fact succeed in school, are engaged with their families and communities, and emerge from their teen years without experiencing serious problems such as substance abuse or involvement with violence. Recent research suggests that it may be time to lay the stereotype of the “wild teenage brain” to rest. This research posits that brain deficits do not make teens do risky things; lack of experience and a drive to explore the world are the real factors. Evidence supports that risky behavior during adolescence is a normal part of development and reflects a biologically driven need for exploration – a process aimed at acquiring experience and preparing teens for the complex decisions they will need to make as adults.^[3] Furthermore, McNeely & Blanchard^[4] described the adolescent years as a “time of opportunity, not turmoil.”

Second only to infant development, adolescents experience rapid development in a short period of time. During adolescence, youth typically gain 50% of their adult body weight, experience puberty and become capable of reproducing, and experience an astounding transformation in their brains. All of these changes occur in the context of rapidly expanding social spheres. Adolescent physical development is often completed by age 18, but brain development requires many more years to reach maturity. Thus, it is imperative for adults and adolescents to understand these vast changes to enjoy this second decade of life.