How was the process of developing a sense of identity during adolescence highlighted?

Erikson's psychosocial development theory.
Erik Eriksson was the psychologist that came up the psychosocial theory which is also known as psychoanalytic theory.

At adolescence, which is from age 13 - 19. The psychosocial crisis for the stage is "identity vs Role confusion". Adolescent achieve a sense of identity regarding who they are and where their lives are headed. This stage marks the transition from childhood to adulthood.