To Freud, the id, ego, and superego were the component parts of the psychological self. The id represented an element of the unconscious that demanded instant gratification. This was associated with infancy, but it remained part of the person's psyche even as they grew up. Sometimes, however, especially as a person grew older, instant gratification of all desires could actually be self-defeating. The recognition of this, which was the result of socialization, is known as the ego. The ego was more rational and pragmatic, and recognized the utility of putting off gratification of desires. The superego was moral, and also developed to some extent through socialization. Pursuit of "animal" urges was not just inhibited by practical concerns, but by the conscience. Often people managed to sublimate the desire to achieve gratification, restricted by both the ego and superego, into more productive activities.

Sigmund Freud pioneered several theories and methods that created the field of Psychoanalysis, and is considered the most important figure in modern psychology theory and practice.

One of Freud's most enduring theories is a hierarchical structure for the conscious and unconscious mind. In his view, the mind -- that is, the part of a reasoning human that dictates behavior and decision, with or without deliberate thought -- is composed of three parts: the Id, the Ego, and the Super-ego.

1. The Id is is "animal" part of the mind, the instinct-driven part that makes snap decisions and motivates emotional responses. The Id is typically thought of as an Unconscious Motivator and operates on a preference for pleasure and avoidance of pain.
2. The Ego is the rational, "awake" part of the mind, the part that reasons and deliberates before action. The Ego is typically thought of as a Conscious Motivator in that it is deliberately called into action by the person -- prices or important decisions with multiple factors to consider fall under the Conscious mind.
3. The Super-ego is the "moral" part of the mind, the part that looks critically on all decisions and consequences and passes judgement according to a person's learned ethical or belief system. The Super-ego is typically considered an Unconscious Motivator in that it operates similarly to the Id, above rational thought.

Although he theorized these parts late in his career, they have become standard reference for modern psychoanalysts, and are also ingrained in popular thought as "official" parts of the mind.