Lecture Notes: The Two-Step Flow, or Why Influencers Are an Old Idea

Executive summary

• The concept: the two-step flow holds that media messages often reach the public indirectly, first through "opinion leaders" who pay close attention to media and then pass ideas on to the people around them.
• The origin: a study of voters in Erie County, Ohio, during the 1940 U.S. presidential campaign, later developed by Elihu Katz and Paul Lazarsfeld in Personal Influence (1955).
• The digital shift: opinion leaders now have public audiences. According to Pew Research Center (2024), about one in five U.S. adults, and 37 percent of those under 30, regularly get news from news influencers.
• The executive lesson: reaching the audience is no longer enough. Campaigns must understand who the audience trusts, and why.

The surprise in Erie County

In 1940, Paul Lazarsfeld, Bernard Berelson and Hazel Gaudet set out to measure how the presidential campaign changed voters' minds. They interviewed a panel of residents in Erie County, Ohio, repeatedly over several months. They expected to find the influence of newspapers and radio.

What they found was more modest and more interesting. Few voters changed their minds, and those who did often cited conversations with other people more than media coverage. In The People's Choice (Lazarsfeld et al., 1944), the authors proposed a hypothesis: ideas often flow from radio and print to opinion leaders, and from them to the less active sections of the population.

That sentence became one of the most influential ideas in communication research.

The definition

The two-step flow has three components.

1. Step one: mass media reach a relatively small group of people who are especially attentive to a subject.
2. Step two: those people, the opinion leaders, interpret and pass on that information through personal conversation.
3. The filter: along the way, the message is selected, reframed and given credibility by someone the receiver knows and trusts.

Katz and Lazarsfeld (1955) refined the idea in Personal Influence, based on research in Decatur, Illinois. Two findings stand out. First, opinion leaders were not a separate elite. They were found at every social level and were usually similar to the people they influenced. Second, leadership depended on the topic: the person consulted about fashion was not the one consulted about public affairs.

Katz (1957) later summarized why personal influence mattered. Compared with media, a trusted acquaintance is flexible, responds to objections and carries the weight of a relationship. A conversation can persuade where a broadcast cannot.

The critics

The theory has been debated for decades, and its limits are part of the lesson.

• Too simple. Later research found that information often flows in many steps and in many directions, and that opinion leaders also seek advice from others.
• Information versus influence. Many people learn news directly from media. Personal influence may matter more for interpretation and decision than for first exposure.
• A changing environment. Bennett and Manheim (2006) argued that a "one-step flow" was emerging: digital technologies let communicators target individuals so precisely that the intermediary step could be bypassed.

Opinion leaders in the digital ecosystem

The irony is that the digital environment has not eliminated the second step. It has made it visible, measurable and commercial.

From neighbors to creators

The opinion leader of 1940 talked to a few friends. Today's news influencer may speak to millions. Pew Research Center (2024) found that 21 percent of U.S. adults regularly get news from news influencers on social media, rising to 37 percent among adults under 30. Of the 500 influencers it studied in depth, 77 percent had no past or present affiliation with a news organization.

Trust is still the currency

What made the opinion leader persuasive in Decatur still applies: perceived similarity, a sense of relationship and credibility on a specific topic. Followers often experience creators as people they know, which gives their recommendations a weight that institutional advertising rarely achieves.

Both models now coexist

Bennett and Manheim's one-step flow is real: micro-targeted ads reach individuals directly. But the most effective digital messages are often those that travel through trusted intermediaries, whether a creator, a community leader or a friend in a group chat.

Applications for campaigns and leaders

1. Map the intermediaries. For each audience and each issue, identify who people actually listen to. The answer is rarely the most famous account.
2. Respect topic specificity. An influencer trusted on lifestyle is not automatically credible on public policy. Choose messengers by subject, not by follower count.
3. Equip, do not script. Opinion leaders persuade because they sound like themselves. Provide accurate information and context, and let them translate it.
4. Disclose paid relationships. The two-step flow works because of trust. Undisclosed sponsorship turns influence into manipulation and, when revealed, destroys the credibility it was meant to borrow.
5. Listen before you speak. Intermediaries also carry information upward. Monitoring what trusted voices say about an issue is one of the best early-warning systems for a crisis.

Closing note

The researchers in Erie County went looking for the power of mass media and found the power of conversation. Eighty years later, the conversation has moved to screens and the opinion leaders have audiences of their own, but the core insight holds. People rarely change their minds because of a message alone. They change them because someone they trust helped them understand it.

References

Bennett, W. L., & Manheim, J. B. (2006). The one-step flow of communication. The Annals of the American Academy of Political and Social Science, 608(1), 213–232. https://doi.org/10.1177/0002716206292266

Katz, E. (1957). The two-step flow of communication: An up-to-date report on an hypothesis. Public Opinion Quarterly, 21(1), 61–78. https://doi.org/10.1086/266687

Katz, E., & Lazarsfeld, P. F. (1955). Personal influence: The part played by people in the flow of mass communications. Free Press.

Lazarsfeld, P. F., Berelson, B., & Gaudet, H. (1944). The people's choice: How the voter makes up his mind in a presidential campaign. Duell, Sloan and Pearce.

Pew Research Center. (2024, November 18). America's news influencers. https://www.pewresearch.org/journalism/2024/11/18/americas-news-influencers/