Max McCombs is widely known among communication scholars, for he has devoted almost four decades to building agenda setting from a successful hypothesis into a robust and popular theory of how news influences the salience of issues. From the initial McCombs and Shaw (1972) Chapel Hill study, done during the 1968 presidential election and published in Public Opinion Quarterly, this theory has engendered more than 400 published studies. What McCombs calls the invisible college of agenda-setting scholars includes researchers from every settled continent. British scholars Blumler and Kavanagh (1999) once observed, Among the field's master paradigms, agenda setting may be most worth pursuing (p. 225). McCombs's contribution to communication theory extends beyond the elucidation of agenda setting itself; he has helped reestablish scholarly appreciation for the power of media in influencing public perceptions of the political world. Acknowledging and expanding on Walter Lippmann's (1922) insights in Public Opinion, he has shown that media messages have great influence on the pictures in our heads. The Chapel Hill study's correlations between the media agenda and the public agenda offered a finding that has become scholarly history. Lowery and Defleur (1995) list the early agenda-setting studies among 15 milestones in communication research. Magnitude of Contribution To understand the magnitude of McCombs's contribution to communication theory, it should be remembered that from the 1940s through the 1960s, prevailing scholarly wisdom held that media exerted little influence. In The People's Choice, Lazarsfeld, Berelson, and Gaudet (1948) had shown that social processes, and not media messages, the prime influencers in the 1940 election. In a later study titled Voting, Berelson, Lazarsfeld, and McPhee (1954) found the surface effects of newspapers and radio in the political campaign were not impressive (p. ix). Klapper (1960) offered the observation that mass communication ordinarily does not serve as a necessary and sufficient cause of audience effects, but rather functions among and through a nexus of mediating factors (p. 8). From his early days as a New Orleans Times-Picayune reporter, however, McCombs knew that news stories influenced people. He and Shaw designed their 1968 Chapel Hill study to seek news influence in a different realm: voters' perceptions of the most important problems of the day. As McCombs would later explain, he and Shaw sought media influence at the cognitive level, rather than at the affective or behavioral level. They found gold in this initial study (McCombs & Shaw, 1972). Correlating the media agenda (as measured by content analysis) with the public agenda (as measured by a survey of voters), yielded a .967 rank order correlation on major campaign issues, and a .979 correlation on minor issues. The study revealed two other interesting conclusions. McCombs and Shaw designed their research specifically to attack the prevailing wisdom that voters' selective attention to news stories, as cued through social processes, would nullify media influence. They showed conclusively how voters' perception of the importance of issues was determined by media attention to those issues (in terms of numbers of stories), rather than by the voters' selective attention. The landmark agenda-setting study also showed a high degree of correlation among the various media. That is, television news, magazines, and newspapers all agreed significantly on how much coverage they gave to the various issues of the day. Both CBS and NBC network news agendas, for example, had a .66 correlation with the New York Times agenda. As news channels proliferated, this finding served as an important benchmark for future research on inter-media agenda setting. The Charlotte Study Having established high correlations between the media agenda and the public agenda, McCombs and Shaw set out to establish time-order, the second condition necessary for determining causal influence of media messages. …
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