This paper reports a computer simulation at the level of the organism. Freud's counterwill theory is translated into a computer model, using Forrester's system dynamics language. Three simulation runs are described to illustrate the behavior of the system in comparison with Freud's description of patient behavior. It is shown that system dynamics methodology is an effective device to expose the complex structure of psychoanalytic theory. The experimental study of psychoanalytic theory has been predominantly directed to isolated propositions.However, a system dynamics representation of the theory may stimulate academic psychology to a more comprehensive and integrated investigation of psychoanalytic theory. cc3IGMUND Freud (1892Freud ( -1893 S drew his inspiration for the counterwill theory from the case of a young "mother who was unable to feed her newborn baby till hypnotic suggestion intervened." In the present paper we develop a formalization of Freud's verbal model into a computer simulation model using Forrester's (1968) systems dynamics language. Three simulation runs are described to illustrate the behavior of the computer model as compared with Freud's description of patient behavior. The paper concludes with a discussion of the relevance of attempts to explore psychoanalytic theory with the help of system dynamics methodology.