Part of a series exploring how people grow into adulthood, this training explores the
psychoanalytic theory of human development. Psychoanalytic theory is the work of Sigmund Freud (d. 1938), a nontraditional physician who founded the psychological profession 100 years ago. Freud believed that human development is powered by conflicting forces within us, and that people do what they do for reasons that are hidden in the unconscious. He believed these internal conflicts focus in different areas of the body, and that they change as a person grows. Freud identified 5 stages of human
development, believing that passing successfully through all 5 was needed for a healthy adult life, and that getting stuck or fixated in any stage led to unhealthy personality traits. A second key psychoanalytic theorist, Melanie Klein (d. 1960), studied the unconscious process of attachment to others, which relates to our experience all the way back in infancy, but which impacts how we relate to others throughout life. We can use this idea of unconscious explanations for why people do what they do, to better understand ourselves and the families we work with.