Main Theorist - Sigmund FreudKey ConceptsPsychosexual Stages - Freud believed personality develops through five stages (oral, anal, phallic, latency, and genital), where pleasure focuses on different body parts. Conflicts at any stage affect adult personality.Unconscious Mind - Much of our thoughts, feelings, and memories are hidden in the unconscious, influencing behavior without us realizing it.Early Childhood Experiences - Freud emphasized that early childhood events shape our adult personality and mental health, as unresolved conflicts from childhood affect us later in life.