Early theories of media influence pictured audiences as passive receivers who'd believe roughly whatever the news told them. Decades of research undercut that picture — but a narrower, better-supported claim survived it. Agenda-setting theory holds that news coverage rarely succeeds at telling people what conclusion to reach on an issue, but reliably succeeds at something else: shaping which issues people consider important enough to have a conclusion about in the first place.
The Chapel Hill study that gave the theory its evidence
The theory's founding evidence came from a 1968 study by Maxwell McCombs and Donald Shaw, who surveyed undecided voters in Chapel Hill, North Carolina during that year's presidential election, asking them which issues they considered most important, and separately analysed the content of the news outlets those same voters actually consumed. The two rankings matched closely — the issues that dominated the news were the same issues voters ranked as most important — and because the correlation held even on issues with little independent, first-hand relevance to most voters' daily lives, McCombs and Shaw argued the media's issue emphasis was shaping public priorities rather than merely reflecting them.
From "which issues" to "which traits" — the second level
Later work extended the theory into what researchers call "second-level" agenda-setting: media coverage doesn't just make an issue or a person prominent, it also emphasises particular attributes of that issue or person over others, and audiences tend to pick up on which attributes coverage treats as central. Covering a candidate mainly through their policy positions versus mainly through a personal scandal doesn't just change how much attention the candidate gets — it changes which specific traits the audience uses to judge them, without necessarily changing whether the judgment is positive or negative.
What we're still unsure about
Agenda-setting was developed and tested mostly in an era of a handful of major broadcast and print outlets sharing a broadly similar news agenda; in a fragmented, algorithm-curated media environment where different audiences see almost entirely different coverage, or set their own agenda through social platforms rather than receiving one from an editor, researchers are still working out how much of the original theory transfers cleanly and how much needs rebuilding. Whether algorithmic feeds function as a new kind of agenda-setter, or whether the whole "single shared agenda" premise the theory was built on simply no longer holds in a meaningful way for most audiences, remains a genuinely open question in communications research.
This sits inside Mass Media & Cultural Production, one of seven topics in Culture, one of four domains in Sociology, one of seventeen subjects the app can quiz you on.