After the decline of the ancient world, no elaborate systematic study of propaganda appeared for centuries—not until the Industrial Revolution had brought about mass production and raised hopes of immensely high profits through mass marketing. Near the beginning of the 20th century, researchers began to undertake studies of the motivations of many types of consumers and of their responses to various kinds of salesmanship, advertising, and other marketing techniques. From the early 1930s on, there have been “consumer surveys” much in the manner of public opinion surveys. Almost every conceivable variable affecting consumers’ opinions, beliefs, suggestibilities, and behaviour has been investigated for every kind of group, subgroup, and culture in the major capitalist nations. Consumers’ wants and habits were studied for a limited time in the same ways in the socialist countries—partly to promote economic efficiency and partly to prevent political unrest. Data on the wants and habits of voters as well as consumers are now being gathered in the same elaborate ways in many parts of the world. Beginning in the early 21st century, many Web sites (especially social networking platforms) and Internet service providers, as well as thousands of applications developed for use with browsers and smartphones, collected massive amounts of personal data about the consumers who used them, generally without their informed consent. Such data potentially included consumers’ ages, genders, marital status, medical histories, employment histories and other financial information, personal and professional interests, political affiliations and opinions, and even geographic locations on a minute-by-minute basis. The collected data was then sold to information or data brokers, who aggregated it and sold it to advertising firms, who in turn used it to identify potential customers for their corporate clients and to make their commercial messages more effective.

Large quantities of such information were also collected about voters and drawn upon for nationwide political advertising campaigns costing billions of dollars annually. Such messages have taken up a high percentage of advertising space or time on social networking platforms and other popular Web sites, in newspapers and magazines (both electronic and printed), and on radio and television. Critics have argued that advertising expenditures on such a scale, whether for deodorants or presidents, tend to waste society’s resources and also to preclude effective competition by rival producers or politicians who cannot raise equally large amounts of money. A rising tide of consumer resistance and voter skepticism has led to various attempts at consumer education, voter education, counterpropaganda, and proposals for regulatory legislation. Most such proposals in the United States have been unavailing.

As far back as the early 1920s, there developed an awareness among many social critics that the extension of the vote and of enlarged purchasing power to more and more of the ignorant or ill-educated meant larger and larger opportunities for both demagogic and public-spirited propagandists to make headway by using fictions and myths, utopian appeals, and “the noble lie.” Interest was aroused not only by the lingering horror of World War I and of the postwar settlements but also by publication of Ivan Pavlov’s experiments on conditioned reflexes and of analyses of human motivations by various psychoanalysts. Sigmund Freud’s Group Psychology and the Analysis of the Ego (1922) was particularly relevant to the study of leaders, propagandists, and followers, as were Walter Lippmann’s Public Opinion (1922) and The Phantom Public (1925).

In 1927, an American political scientist, Harold D. Lasswell, published a now-famous book, Propaganda Technique in the World War, a dispassionate description and analysis of the massive propaganda campaigns conducted by all the major belligerents in World War I. This he followed with studies of communist propaganda and of many other forms of communication. Within a few years, a great many other social scientists, along with historians, journalists, and psychologists, were producing a wide variety of publications purporting to analyze military, political, and commercial propaganda of many types. During the Nazi period and during World War II and the subsequent Cold War between the U.S. and the Soviet Union, a great many researchers and writers, both skilled and unskilled, scholarly and unscholarly, were employed by governments, political movements, and business firms to conduct propaganda. Some of those who had scientific training designed very carefully controlled experiments or intelligence operations, attempting to quantify data on appeals of various types of propaganda to given reactors.

In the course of this theory building and research, the study of propaganda advanced a long way on the road from lore to science. By the second half of the 20th century, several hundred more or less scholarly books and thousands of articles had shed substantial light on the psychology, techniques, and effects of propaganda campaigns, major and minor.

Eventually nearly every significant government, political party, interest group, social movement, and large business firm in the advanced countries developed its own corps of specialized researchers, propagandists, or “opinion managers” (sometimes referred to as information specialists, lobbyists, legislative representatives, or vice presidents in charge of public relations). Some have become members of parliaments, cabinets, and corporate boards of directors. The most expert among them sometimes are highly skilled or trained, or both, in history, psychiatry, politics, social psychology, survey research, and statistical inference.

Many of the bigger and wealthier propaganda agencies conduct (overtly and covertly) elaborate observations and opinion surveys, among samples of the leaders, the middle strata, and the rank and file of all social groups, big and little, whom they hope to influence. They tabulate many kinds of data concerning those contents of the Internet, the press, films, television, and organizational media that reach given groups. They chart the responses of reactors, through time, by statistical formulas. They conduct “symbol campaigns” and “image-building” operations with mathematical calculation, using large quantities of data. To the ancient art of rhetoric, the “technique of orators,” have been added the techniques of the psychopolitical analyst and the media specialist and the know-how of the administrators of giant advertising agencies, public relations firms, and governmental ministries of information that employ armies of analytic specialists and “symbol-handlers.”

It is a commonplace among the highly educated that people in the mass—and even people on high educational and social levels—often react more favourably to utopian myths, wishful thinking, and nonrational residues of earlier experiences than they do to the sober analysis of facts. Unfortunately, average citizens who may be aware of being duped are not likely to have enough education, time, or economic means to defend themselves against the massive organizations of opinion managers and hidden persuaders. Indeed, to affect them they would have to act through large organizations themselves and to use, to some extent, the very means used by those they seek to control. The still greater “curse of bigness” that may evolve in the future is viewed with increasing concern by many politically conscious people.