The id (Latin for “that thing”) is present at birth and developmentally is the oldest of the three psychological structures proposed by Sigmund Freud as part of the mind. According to Freud, neither the ego nor the superego is active or even formed so early in the individual’s development, when the id serves as the storehouse for all the instincts. Initially, all the psychic energy available in the system is invested in the id, which uses this energy to satisfy basic needs through reflexive or reflexive-like behaviors. These needs must first be satisfied if (1) the organism is to survive (again, self-preservation), and (2) the organism is to move on to higher, less biologically and more socially based needs (again, species preservation).
In its most basic form, the id is an inborn biological structure that has as its purpose immediate gratification and reduction of tension. As the initial reservoir of psychic energy, it accomplishes this primary goal of tension reduction through the pleasure principle (also referred to as the principle of lust, the pleasure-pain principle, or the lust-unlust principle). The pleasure principle states that the primary goal in mental operations is the achievement of pleasure through gratification.
Controlled entirely by the pleasure principle, id energy is under no constraints and makes no distinction between fantasy and reality. Thought that does not distinguish what is real from what is not real is called primary process thinking. For example, in the older child or adult, a need can become temporarily satisfied by means of remote representation of the drive object (or that which satisfies a need), perhaps in the form of an image. Daydreaming is thought to exemplify this type of thinking. For example, thinking about a favorite food when one is hungry may relieve hunger pangs for a short period of time. Although daydreaming or primary process thinking satisfies only temporarily, it is an effective way of discharging stored energy and reducing tension so that the tension does not dominate one’s thinking.
The psychic energy associated with the id is unconscious in that the individual is unaware of it and cannot talk or think about it. All of the psychic energy associated with the id is unlabeled, or without any verbal associations. It is not available to higher mental processes, and the emotions and feelings associated with it cannot be considered on a rational basis. For this reason some Freudian psychologists believe that events that occur when the child is preverbal cannot be remembered.
The unconscious urges of the id remain active throughout life, but, as healthy development proceeds, a smaller and smaller proportion of psychic energy becomes associated with the id, and more and more psychic energy becomes associated with the more socially adaptive ego and superego.
Reference:
Jones, E. (1953/1957). Sigmund Freud: Life and work (3 vols.). London: Hogarth Press.