The theoretical principle that humans make decisions to seek pleasure and minimize pain.
Among other principles, Freudian psychology states that there is a basic human tendency to seek pleasure and avoid pain. It arises from the desire for unrestrained expression of both the life instinct (Eros) associated with sexuality and the death instinct (Thanatos) associated with aggression and destructiveness. Freud described the pleasure principle in terms of the need to discharge or reduce tensions—experienced as pain or discomfort— created internally or by external stimuli. The id, which operates on the pleasure principle, is the instrument for discharging these tensions. However, it is held in check by the ego, operating on the opposed reality principle, which mediates between the primitive desires of the id and the constraints of the external world.
The promptings of the pleasure principle, which are often compared to the demands of a child, seek immediate gratification and are ungoverned by social or moral rules. The reality principle opposes many of these promptings, denying them altogether or postponing gratification either until a socially appropriate time (waiting until a meal to eat) or so that greater pleasure may be achieved in the long run (studying for a degree or training for a sport).
Freud, Sigmund. New Introductory Lectures on Psychoanalysis. New York: W. W. Norton, 1933.
Hall, Calvin S. A Primer of Freudian Psychology. New York: Harper and Row, 1982.