Id

Id, in the theory of psychoanalysis, one of the three basic elements of personality, the others being the ego and the superego. The id can be equated with the unconscious of common usage, which is the reservoir of the instinctual drives of the individual—biological urges, wishes, and affective motives. The id is dominated by the pleasure principle, through which the individual is pressed for immediate gratification of desires. According to the theory of Sigmund Freud, the energy behind the instinctual drives of the id is known as the libido—a generalized force which is basically sexual in nature—through which the sexual and psychosexual nature of the individual finds expression.