Final answer:
Erik Erikson developed the theory of expressing your self-concept throughout your life span. His theory includes eight stages of development that people move through throughout their lives.
Step-by-step explanation:
Erik Erikson, a psychologist, developed the theory of expressing your self-concept throughout your life span. He believed that personality continues to change over time and is never truly finished. According to Erikson, people move through eight stages of development throughout their lives, with each stage representing a conflict or developmental task.