ABSTRACT
The idea that what has been learned in a certain state of mind or brain is best remembered in that state is an old and familiar one in psychology. The credit for this concept—one that I refer to as state dependent memory—goes to an astute French aristocrat, the Marquis de Puységur (Chastenet de Puységur, 1809; Ellenberger, 1970). In 1784, Puységur discovered that although a person might appear, upon awakening, to be amnesic for events that had occurred during hypnosis, memory for these events returned once the individual reentered a state of “magnetic sleep”—Puységur’s term for hypnosis. Decades later, a French physician named Azam (1876) related a strikingly similar observation in connection with the case of a young woman who suffered sudden attacks of hysterical somnambulism, or “pathological sleep,” as the disorder was then known. And in an article published in 1910, Morton Prince conjectured that the reason most people have difficulty remembering their dreams is not because they do not want to remember—as Freud (1953) and other psychodynamicists of the day were claiming—but rather, because they cannot remember, owing to the dissimilarity between the states of “natural sleep” and ordinary wakefulness.
