Propaganda by Edward Bernays, 1928, Excerpts
Trotter, Le Bon, Wallas, and Walter Lippmann established that the group has mental characteristics distinct from those of the individual, and is motivated by impulses and emotions which cannot be explained on the basis of what we know of individual psychology. If we understand the mechanism and motives of the group mind, is it not possible to control and regiment the masses according to our will without their knowing about it? The recent practice of propaganda has proved that it is possible, at least up to a certain point and within certain limits.
No serious sociologist any longer believes that the voice of the people expresses any divine or specially wise and lofty idea. The voice of the people expresses the mind of the people, and that mind is made up for it by the group leaders in whom it believes and by those persons who understand the manipulation of public opinion. It is composed of inherited prejudices and symbols and clichés and verbal formulas supplied to them by the leaders.
Human desires are the steam which makes the social machine work. Only by understanding them can the propagandist control that vast, loose-jointed mechanism which is modern society.