Final answer:
Valya is representing Sigmund Freud, who emphasized that childhood experiences shape our personality and behavior through the psychoanalytic theory.
Step-by-step explanation:
Valya is representing the famous psychologist Sigmund Freud while role-playing in her introductory psych class. Freud is well-known for his theory that childhood experiences are pivotal in shaping an individual's behavior and personality. He posited that the unconscious mind has a substantial impact on the behavior of individuals, which can be traced back to our earliest developmental stages. Freud's theory, known as the psychoanalytic theory, places significant emphasis on early experiences, particularly those related to psychosexual stages of development.