In 1922, Walter Lippmann suggested the very first idea of agenda-setting in his book “Public Opinion”, and Bernard Cohen (1963) said “The media may not tell us what to think, but they are stunning successful in telling us what to think about”. Those concepts assumed that with the limited ability and innate curiosity of human beings, most people rely on media institutions to gain information outside family, neighborhood and workplace. Thus the media organizations have the priority to choose which information is quality enough to be the most important, which is not, and the information emphasized by the media could salience transfer to the public.
To verify this concept, McCombs and Shaw conducted the first empirical research, which had been published in 1972, since then the basic agenda-setting theory has been established. After the first research published, they retested the reliability and validity of that research, and developed contingent conditions to enhance and limit this theory. Then many researchers became involved in this field, and the detail and extension of agenda-setting theory started. Weaver, Graber and McCombs and Eyal (1976) extended the idea of agendas into politics and election campaign domains. Since 1980s the map of agenda-setting has been becoming complex, continuously. Under the origin theory frame of agenda-setting, analysis of the salience of media agenda to public agenda, the process of agenda-setting, and the affect of three levels agenda-setting detailed this theory. Also, the idea of agenda-setting theory has been explored into several domains, which include political advertising, consequences and subsequent behavior of audience, and international marketplace and so forth. In addition, the integration of research areas flourished, such as intermedia agenda setting (the salience transfer from one medium to another), priming, framing and agenda-setting, Gatekeeping research with agenda-setting, and the common conceptual ground—need for orientation. Each part mentioned above interweaving with each other comes into being the net of agenda-setting theory.
This literature review will use three levels of agenda setting effects as entry point to discussion the core concept of agenda setting theory—the prominent transference from media agenda and public agenda. Five original published researches will be described and analyzed. Although many parts aforementioned can not be included in those five studies, with the long history and complicated net of agenda-setting theory, three levels of agenda setting could be an appropriate point cut, just as Guo, Vu and McCombs (2012) suggest:” agenda-setting has evolved from a focus on media effects on the public’s perception of the most important issues of the day to a theory elaborating a hierarchy of communication effects, its core is three levels of agenda-setting”. Considering of that, the following contents will include (1) the explanation of each level agenda-setting....