 It is generally considered that journalist Walter Littman conceptualised the term agenda setting in the early 1920s. Littman understood that the media constructed the world for the individual, and so the way people thought about the world was not really what they thought about the world. Rather, it was the way in which they thought about the world that was constructed for them by media representations. Not simply, the agenda setting theory asserts that the media can set the agenda for public opinion by simply privileging certain stories or issues over others. By 1972, Maxwell McCombs and Donald Shaw decided to formalise the theory by situating the idea in context. They chose to focus on the 1968 presidential campaign using media materials from Chapel Hill, North Carolina. They attempted to match what the Chapel Hill voters said were key issues of the campaign with the actual content of the mass media used by them during the campaign. They found that the media appear to have exerted a considerable impact on voters' judgments of what they considered the major issues of the campaign. In short, the data suggests a very strong relationship between the emphasis placed on different campaign issues by the media and the judgments of voters as to the salience and importance of various campaign topics. So how does agenda setting take place? According to Cammie Barnes, there are several processes at work, namely salience transfer, priming, framing and gatekeeping. Barnes describes salience transfer as the capacity of the media to influence the relative importance individuals attached to policy issues. Barnes references the famous experiment by Ian Gar, Peters and Kinder in which experimental groups were given baseline priorities, but were then exposed to different news broadcasts with different policy emphases over a period of four days. When the groups were asked to rate the priorities again, the researchers found that the subjects issue rankings re-aligned to match the agenda that they were given. Priming on the other hand is the way the media can draw attention to issues even in a way that appears to have no agenda at all, but actually provides a context that is being put into place in order to set the stage or prime the audience for particular issues. Ron Smith explains that the amount of time and space that media devote to an issue make an audience receptive and alert to particular themes. Likewise, audience perception of events are impacted by historical contexts with which they are familiar, through experience or through the media. Smith gives the example of the way that media reporting may be very strong leading up to an event such as the Olympics, the Super Bowl or a World Cup, making it almost impossible for audiences to ignore the event. Another way in which agenda setting takes place is through the process of framing. Famous sociologist Irving Goffman in 1974 put forward a concept called frame analysis, in which he examined the ways that media and other influential institutions construct a suitable environment or frame to enable the interpretation of ideas in a particular way. Ron Smith gives the example of initial reporting through which the media may present the facts of a story in such a way that the audience is given a particular point of view or a frame of reference and interpretation. By doing so, the media have thus presented a frame through which the story is interpreted by audiences from then on, so it sets the baseline for future reporting on the issue. The last idea we will cover is gatekeeping. Gatekeeping as a media concept has been around for many years. Put simply, gatekeepers are those individuals or institutions who have the power to control the flow of information. They keep watch over the gate of content flow, if you will. However, the processes of gatekeeping are radically changing as new media technologies enable a variety of stakeholders to change and redirect the flow of media materials. As Barnes points out, the new media environment creates multiple gates through which information passes out to the public, both in terms of the sheer number of sources and the speed with which information is transmitted, as well as the types of genres the public uses for political information, like movies, music, docu-dramas, talk shows and so on. Citizen journalists, news bloggers and participatory media all contribute to the vast amount of not only news but new opinions and new agendas. This can be positive because the flow of information is broken loose from the corporate stronghold, but also there are negatives too because credibility, bias and accuracy can be difficult to monitor and ascertain. But then again, we have just seen that actually, they have always been difficult to monitor and ascertain.