This article deals with the position of psychoanalysis with respect to social psychology. It aims to pinpoint the work of the unconscious in the forming of masses.Our approach seeks to revisit the contemporary pertinence of Freud at the time when he was studying remarks by an eminent theoretician of social psychology: Wilfred Trotter.Here we try to grasp the dialectic of the drive and the function of the ideal that Freud puts forward in answer to Trotter’s hypothesis on the innate gregarious instinct, which he takes as a self-evident fact whose various manifestations can only be studied on the conscious plane.