Sigmund Freud believed human behavior is motivated by the id, ego, and superego. The id seeks pleasure and avoids pain instinctively. The ego uses reason and logic to satisfy the id's desires in socially appropriate ways. The superego incorporates moral values learned from parents and society, trying to persuade the id and ego to act morally rather than for pleasure alone. Freud saw the id as chaotic and animal-like, the ego balancing it with reality, and the superego developing last to impose moral standards.