What are the major contributions of Sigmund Freud to the study of child's development?

Sigmund Freud made significant contributions to the study of child development through his psychoanalytic theory, emphasizing the role of the unconscious mind, early childhood experiences, and the impact of parents on a child's development. He introduced concepts such as the Oedipus complex, stages of psychosexual development, and defense mechanisms that continue to influence the field of psychology today. Freud's work helped shape our understanding of how early experiences can shape personality and behavior in children.