Childhood is the formative period, when an individual is socialized. Socialization takes place in different settings, e.g., the home, school, church and club, and through interaction with others, including parents, teachers and peers. These factors influence a child's concept of acceptable social behavior, morality and sex roles.
As individuals move from childhood to adulthood, they develop an "identity," or self-understanding of who they are and where they're going in life. Internalized beliefs, norms and values guide their behavior. These are also the standard they measure the behavior of others by, especially peers. If the behavior of peers conflicts with internalized expectations, adolescents often develop norms and values that conflict with those of their parents. The development of one's own norms and values, though, is crucial for entry into adulthood.
In adulthood, people face a constant need to adapt because their social structures are more complicated. They belong to many different institutions and organizations, for example, college, work or church, each of which influences behavior. Moreover, some transitions, for example, from college student to military recruit, demand that they internalize new sets of norms and values. Some of these can bear little resemblance to those they embraced in childhood or adolescence.
As people age, they experience dramatic changes, including retirement, declining health and the death of a spouse, but are still as capable of adapting to change as they were when they were younger. At this state in life, however, their values are well established and their behavior is unlikely to change.