Few psychoanalytic concepts have been used as widely as the concept of instinct for explaining abnormal development. Under this orientation, obesity and other eating disorders are conceived of as resulting from disturbances during the oral phase. Yet the concept of instinct has been widely debated. Freud himself proposed many theoretical formulations and remained critical of all his efforts to formulate a fixed theory of instinct. A definite progression can be recognized in his concept of the instinctual drives, represented in the id, from the reflex arc scheme of a self-contained closed system, unrelated to the outer world (1915), toward a more modern biological view of instinct as "a tendency innate in living organic matter impelling it towards the reinstatement of an earlier condition, one which it had to abandon under the influence of external disturbing forces" [emphasis added]; i.e., instincts are influenced by and interact with life experiences (1920). The notion persists that there is an inborn capacity to recognize and fulfill bodily needs.
I shall examine in this paper the question of whether and how much organized awareness of hunger is present at birth. When Freud formulated his concept of libido, he specified that it was a parallel to hunger, which he felt was a generalized expression for the instinct of nutrition (1905). Hunger is so much a part of everyday language that it is easily overlooked that the word embraces a rather complex concept conveying many different meanings. Hunger refers to the physiologic state of severe food deprivation, starvation, or to widespread famine. Hunger denotes also a psychological experience, that is, the complex, unpleasant, and compelling sensation an individual feels when deprived of food, which results in searching, even fighting for food to relieve the torment. For a psychological study, it is of the utmost importance to separate the physiological state of nutritional need from the perception and conceptual awareness of this state.
