Id, Ego, Superego Model: 

Id, ego, superego model, as conceived by Sigmund Freud, are three distinct, but interacting “agents in the psychic apparatus.” They describe the basic structure of mental life as Freud encountered it in his psychoanalytic practice. Freud used the German terms das Es, Ich, and Über-Ich, (the it, I, and over-I). His translators chose the Latin terms id, ego and superego and have remained in use. Freud compared the ego-id relation to a rider on horseback, harnessing the horse’s superior energy while allowing it some satisfaction of its urges. The ego transforms the id’s will into action.

• Id is the mind’s primitive/instinctual part, referring to basic instincts (hunger, thirst, pain avoidance) and containing sexual/aggressive drives and hidden memories. It’s the first part of the personality to develop from birth and entirely unconscious. It operates on the pleasure principle, seeking immediate gratification of needs/desires without considering consequences, social norms, or reality.
• Ego is the integrative agent that directs activity based on mediation between the id’s impulses, real demands from the outside world, and the superego’s moral and critical constraints.
• Superego is the part of the psyche with internalized social rules and norms, largely in response to parental demands and prohibitions in childhood.