most important. Over time, the issues emphasized in news reports become the issues regarded as most important among the public. The agenda of the news media becomes, to a considerable degree, the agenda of the public. In other words, the news media largely set the public agenda. Establishing this salience among the public, placing an issue, event, public figure, or other major element in the news on the public agenda so that it becomes the focus of public attention and thought – and, possibly, action – is the initial stage in the formation of public opinion.
Discussion of public opinion usually centres on the distribution of opinions: how many are for, how many are against, and how many are undecided. That is why the news media and so many news users are so fascinated with public opinion polls, especially during political campaigns. But, before we consider the distribution of opinions, we need to know which elements are at the centre of public opinion. People have opinions on many things, but only a few really matter to them. The agenda-setting role of the news media is their influence on the salience of an object of attention in the news, such as a controversial topic or a political candidate, an influence on whether a significant number of people regard it as worthwhile to hold an opinion about that object.
While many issues compete for public attention, only a few are successful in doing so, and the news media exert significant influence on our perceptions of what are the most important issues of the day. Within professional news outlets, this is not a deliberate, premeditated influence, as in the expression ‘to have an agenda’. Premeditated attempts at influence are the realm of the partisan media, propaganda, advertising, so-called ‘fake news’ sites, and other forms of communication that seek to persuade.3 Professional news media seek to inform, not persuade. And their agenda-setting role stems not from efforts at persuasion, but rather is an inadvertent influence resulting from the necessity of the news media to select and highlight a few topics in their reports about the most salient news of the moment.
This distinction between the influence of the professional news media on the salience of objects in the news and on specific opinions about these objects is summed up in Bernard Cohen’s observation that the news media may not be successful in telling people what to think, but they are stunningly successful in telling their audiences what to think about.4 In other words, the news media can set the agenda for public thought and discussion. Sometimes the news media do more than this. Other times, the news media fail at setting the public agenda. Hence, we will find it necessary in later chapters to expand on Cohen’s cogent observation. But first, let us consider in some detail the initial step in the formation of public opinion, capturing public attention.
Our pictures of the world
Walter Lippmann is the intellectual father of the idea now called, for short, agenda setting. The opening chapter of his 1922 classic, Public Opinion, is titled ‘The World Outside and the Pictures in our Heads’, and summarizes the agenda-setting idea even though Lippmann did not use that phrase. His thesis is that the news media, our windows to the vast world beyond direct experience, determine our cognitive maps of that world. Public opinion, argued Lippmann, responds not to the environment, but to the pseudo-environment constructed by the news media.
Still in print nearly a century after its original publication, Public Opinion presents an intriguing array of anecdotal evidence to support its thesis. Lippmann begins the book with a compelling story of ‘an island in the ocean where in 1914 a few Englishmen, Frenchmen, and Germans lived’. Only the arrival of the mail steamer more than six weeks after the outbreak of the First World War alerted these friends to the fact that they were enemies.5 For Lippmann, who was writing in the 1920s, these are contemporary updates of Plato’s Allegory of the Cave, with which he prefaces the book. Paraphrasing Socrates, he noted ‘how indirectly we know the environment in which nevertheless we live […] but that whatever we believe to be a true picture, we treat as if it were the environment itself’.6
Contemporary empirical evidence
Empirical evidence about the agenda-setting role of the communication media now confirms and elaborates Lippmann’s broad-brush observations. When agenda setting was first proposed, it ran counter to the prevailing paradigm among communication scholars that the mass media had limited effects in changing people’s perceptions and attitudes. Agenda setting, on the contrary, showed that the news media can have strong, direct effects in the short term by influencing not what people think, but what they think about.
However, the empirical currency of agenda setting as a theory about the formation of public opinion came much later than Lippmann’s essay. When Public Opinion was published in 1922, the first scientific investigations of the influence of mass communication on public opinion were still more than a decade in the future. Publication of the first explicit investigation of the agenda-setting role of mass communication was exactly fifty years away.
Systematic analysis of mass communication’s effects on public opinion, empirical research grounded in the precepts of scientific investigation, dates from the 1940 US presidential election, when sociologist Paul Lazarsfeld and his colleagues at Columbia University, in collaboration with pollster Elmo Roper, conducted seven rounds of interviews with voters in Erie County, Ohio.7 Contrary to both popular and scholarly expectations, these surveys and many subsequent investigations in other settings over the next twenty years found little evidence of mass communication effects on attitudes and opinions. Two decades after Erie County, Joseph Klapper’s The Effects of Mass Communication declared that the so-called Law of Minimal Consequences prevailed: ‘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 functions and influences.’8
However, the early social science investigations during the 1940s and 1950s did find considerable evidence that people acquired information from the news media even if they did not change their opinions. Voters did learn from the news. And from a journalistic perspective, questions about learning are more central than questions about persuasion. Most journalists are concerned with informing. Persuasion is relegated to the editorial page and, even there, informing remains central. Furthermore, even after the Law of Minimal Consequences became the accepted conventional wisdom, there was a lingering suspicion among many social scientists that there were major media effects not yet explored or measured. The time was ripe for a paradigm shift in the examination of media effects, a shift from persuasion to an earlier point in the communication process, informing.
After Lippmann, other authors in the social sciences alluded to the idea that the news media influence what people deem to be the relevant issues of the day.9 However, it was only when two young professors at the University of North Carolina’s School of Journalism launched a small investigation in Chapel Hill, North Carolina, during the 1968 US presidential campaign, that the notion was put to proper empirical testing. Their central hypothesis was that the ‘mass media’ set the agenda of issues for a political campaign by influencing the salience of issues among voters. These two professors, Donald Shaw and Maxwell McCombs, also coined a name for this hypothesized influence of mass communication, ‘agenda setting’.10
Testing this agenda-setting hypothesis required the comparison of two sets of evidence: a description of the public agenda, the set of issues that were of the greatest concern to Chapel Hill voters; and a description of the issue agenda in the news media used by those voters. Illustrated in Box 1.1, a central assertion of agenda-setting theory is that those aspects emphasized in the news come to be regarded by the public over time as being important. In other words, the media agenda sets the public agenda. Contrary to the Law of Minimal Consequences, this is a statement about a strong causal media effect on the public – the transfer of salience from the media agenda to the public agenda.
