Identity encompasses the memories, experiences, relationships, and values that create one’s sense of self. This amalgamation creates a steady sense of who one is over time, even as new facets are developed and incorporated into one's identity.
The pioneering identity researcher Erik Erikson proposed an enduring theory of development. Erikson divided the lifecycle into eight stages that each contained a conflict, with the resolution of those conflicts leading to the development of personality. The conflict that occurs during adolescence, Erikson believed, is “identity versus role confusion.”
Adolescents grapple with so many different aspects of identity, from choosing a career path to cultivating moral and political beliefs to becoming a friend or partner. Role confusion pertains to the inability to commit to one path. Adolescents then go through a period of experimentation before committing, reconciling the pieces of their identity, and emerging into adulthood.
Identity formation is most acute during adolescence, but the process doesn’t stop after the teen years. Taking on a new role, such as becoming a parent, can make self-definition a lifelong process.
Erikson also coined the term “ego identity,” which he conceived as an enduring and continuous sense of who a person is. The ego identity helps to merge all the different versions of oneself (the parent self, the career self, the sexual self) into one cohesive whole, so that when unexpected disaster strikes, there's a stable sense of self.
As a person grows older, the overall trend is toward identity achievement. But major life upheavals, such as divorce, retirement, or the death of a loved one, often lead people to explore and redefine their identities.