An essential feature of the technique of psychoanalysis, gradually developed by Freud between 1892 and 1898.
Curiously enough, no one paper by Freud is devoted in its entirely to describing the technique; its origins are described in On the History of the Psychoanalytic Movement (1914), and Two Encyclopedia Articles (1922) describe the technique itself.
The rule of free association states that a [[patient in analysis (or analysand) must verbally express whatever comes into his or her mind during the session, telling all and omitting nothing.
A corresponding rule requires the analyst to listen to all the verbal associations made by the patient, giving no particular importance to anything but paying attention to everything.
The analyst must listen with "evenly suspended or poised attention."
The function of both rules is to prevent the consicous mind from censoring or blocking hte process of interpretation.