If you study American politics or political behavior, you should absolutely read Taylor Carlson’s recent book about information, interpersonal communication, and democratic functioning in the United States. However, if you tell others about the book (and you should), Through the Grapevine would suggest that you should be mindful about the message you pass along—after all, many of us have experienced some version of “the telephone game” at some point in our lives. In the context of Carlson’s book, we might expect that as people’s summaries of the work traverse their academic circles, those narratives could change in meaningful ways. To wit, the reports might evolve to exclude or misrepresent some important details, and they could shift to incorporate individuals’ personal characterizations, political opinions, and their own professional academic agendas. Indeed, given all too familiar communication dynamics, it would probably not surprise us to observe different colleagues coming to different conclusions—all through this secondhand talk—about what the book’s findings mean for the future of American democracy.

Just as we cannot escape rumor, gossip, and other forms of “chained” communication in our everyday (online and offline) lives, Carlson calls our attention to a ubiquitous and persistent feature of our politics: that the information the public relies on is, fundamentally, socially transmitted. Information flows from various sources to the “actively informed,” and then finally to the “casually informed.” She presents a wealth of evidence that this multistep transmission matters because (1) it changes the content and nature of the information, and (2) this altered information influences people’s opinions and propensity to participate in politics.

In engaging and readable opening chapters, Carlson argues that while scholars have long acknowledged the importance of opinion leaders in disseminating information (e.g., Elihu Katz and Paul Lazarsfeld’s 1955 book, Personal Influence), they have done too little to think about who such leaders are, about how they are situated between media sources and other parts of networks, and about the actual content of the information they pass along. She then lays out a theory of what she calls “distorted democracy,” which takes as its starting point how socially transmitted information moves from opinion leaders to broader portions of the public. Here, Carlson builds directly on pioneering ideas about “two-step flows” (e.g., Elihu Katz’s famous 1957 article in Public Opinion Quarterly), but advances on previous takes by giving careful attention to defining and empirically differentiating what she labels the actively informed from the casually informed.

That said, Carlson’s major move and contribution lie with her focus on the content of the information moving between the actively informed and the casually informed parts of the public, and on the consequences that these changes have on public opinion and action. She provides strong reasons to expect that “information becomes sparse, biased, less accurate, and more mobilizing through social transmission” (p. 19), and equally clear logic as to why we should expect this altered information to shape what people know, think, and do.

To test her theory, she draws upon a variety of data sources, including original survey items, analyses of social media messages, and even a few case studies. But the thrust of her evidence comes from her creative adaptation of telephone game experiments. Borrowing from “serial reproduction tasks” (p. 56) developed by psychologists, the basic design involves asking subjects to read a news article and then write a message to someone else about what they just read. The key manipulations in this design involve randomly assigning subjects to write their messages to co-partisans (or not), though Carlson also varies components like the news source (e.g., Fox vs. MSNBC) and the topics of the articles. The messages produced by the subjects are then compared to the original news articles to check for information reduction, distortion, and other changes. Critically, to gauge the impact of socially transmitted information on a variety of outcomes, Carlson uses the secondhand takes produced by subjects in companion designs. Subjects are randomly assigned original news articles versus secondhand summaries of these articles produced by other subjects. Posttreatment outcomes are then compared across the groups that received information either directly from the articles themselves (a stand-in for the actively informed) or from the summaries produced by other participants (a stand-in for being casually informed).

Carlson’s experiments support her theory of distorted democracy. She finds that information is not just lost via social transmission, but that it becomes less accurate, that it takes on partisan biases, and that it may become more mobilizing by including calls to action (Chapter 4). She also carefully demonstrates that those who are casually informed by out-partisans gain less knowledge (Chapter 5), while those casually informed by co-partisans become more polarized (Chapter 6) and more likely to take political action (Chapter 7). What is the overall image that emerges from this constellation of results? Carlson leaves us with a picture of a socially informed American public that is potentially underinformed and polarized, but at the same time politically engaged.

Carlson’s book is well-written and structured, and the evidence from her telephone studies, as well as from her survey and social-media data analyses, is compelling. If there is a limitation to the work—and to be fair, it is one that Carlson acknowledges—it is that her innovative studies do not actually involve direct social interaction between members of the public, and that the way she measures and uses information distortion relies on written text passages rather than verbal or visual communication. Likewise, although the results speak directly to the importance of interpersonal networks in mass publics, her designs do not incorporate social structure or group dynamics.

Still, Carlson’s work is impressive, rigorous, and convincing. She has provided an experimental blueprint that others will follow as they pursue questions relating to information and social influence. Furthermore, she has helped set the stage for subsequent scholarship by asking the right questions and highlighting emerging tensions, all while writing an incredibly accessible book. In this sense, I expect the book to shape the research agendas of scholars studying behavior, communication, and social influence, much like Diana Mutz’s (2006) Hearing the Other Side has in the decades since its publication.

Is socially transmitted information a good thing or a bad thing for American democracy? For her part, Carlson is careful to note that both optimistic and pessimistic assessments find support in her manuscript. However, she would remind us that the point of the book is not to declare a winner in normative debates, but to make us think about the communication dynamics that undergird them. Carlson is not focusing our attention on elite cues, partisan media, or the capacity of the public as it relates to democratic health (although she acknowledges that these things matter). Rather, she urges us to see rethink the quotidian we so often take for granted. Carlson’s message to us is clear: the process by which information moves throughout the public is critically important. Does this hurt or help democracy? The answer to that question depends on who you ask.