Answer:
Sigmund Freud’s Theory of Personality
Step-by-step explanation:
The Austrian psychiatrist Sigmund Freud first described personality development as a series of stages. Of these stages, Freud believed that early childhood was the most important. He believed that personality developed by about the age of five.
Freud’s theory of personality development is described in more detail on pages 268-–273 of Chapter 13, “Personality.”