Reader comments posted on digital news sites are often heavy on invective, hurled from noms d’Internet that allow people to disregard traditional norms of civil discourse. For many of these anonymous snipers, the reported facts are not facts at all, but the unreliable product of paid liars, incompetents, toadies, and haters who dare to call themselves journalists.

How did we get to this pass? A turning point may have been the messy exit of Jayson Blair, who was shot down by journalists themselves and subsequently became a stinking albatross around the neck of everyone in what used to be called straight news. Many Americans, adrift on a stormy sea of proliferating news outlets, now perceive bias, bias everywhere, but not an honest word of reportage.

Meanwhile, a small industry, of remarkably uneven quality, has arisen over the last few decades to examine the supposed unreliability of journalists. The bias police range from ideological outfits like Fairness and Accuracy in Reporting on the left and the Media Research Center on the right to such watchdogs as Keith Olbermann and Bill O’Reilly—not to mention the ombudsmen who now keep an eye on many big-city newspapers (and this magazine).

But while the pack zigs, Farhad Manjoo, until recently the technology columnist for Salon, zags. His first book, True Enough, is a provocative and engaging examination of media bias. Like beauty, argues the author, bias is in the eye of the beholder. So instead of looking at those who report and analyze the news, Manjoo examines their audience. It is a novel and eye-opening approach.

Manjoo argues that “selective perception” is part of the human condition, and that in this era of unlimited news outlets, it is surprisingly easy to get all of your news from places that tell you only what you want to hear—a kind of segregation of the mind. The late Daniel Patrick Moynihan famously observed that we are entitled to our own opinions, but not to our own facts. That, writes Manjoo, is no longer true. Instead he posits “a fundamental shift in the way Americans are thinking about the news. No longer are we merely holding opinions different from one another; we’re also holding different facts.”

This argument is founded on a paradox. “At the same time that technology and globalization have pushed the world together,” writes Manjoo, “it is driving our minds apart.” Shared facts do not mean shared perceptions of what those facts mean. To illustrate his point, the author cites a study involving a much debated 1951 football game between Dartmouth and Princeton. A star Princeton quarterback was injured, and for observers from his own school, this was evidence of foul play, not bad luck in a violent sport. The Dartmouth quarterback was injured as well, but students there simply condemned the losers as whiners.

How could such divergent views arise from a single event? As Manjoo recounts, a Princeton psychologist and a Dartmouth sociologist showed films of the game to students at both colleges. The Dartmouth students reported roughly equal numbers of transgressions by each team, but characterized more of the Princeton errors as “flagrant.” The Princeton students found more than twice as many errors by the other team, most of them flagrant as well.

The researchers concluded that the students had such disparate observations because they chose not to see actions that conflicted with the way they felt about their own teams. In other words, they fitted their perceptions to their feelings, not to the facts.

Manjoo goes on to discuss All in the Family, the celebrated seventies sitcom in which Carroll O’Connor’s Archie Bunker spouted racial and ethnic slurs and argued endlessly with his long-haired son-in-law. Two psychologists—inspired, as it happens, by the football film study—interviewed Midwest high school students about their reactions to the show. As they discovered, almost all viewers found the show amusing. Yet the bigots drew comfort and reinforcement for their views from Archie’s slurs, while those more inclined to think like his son-in-law saw him in a negative light. “Even when the whole country is watching the same thing, in fact, we aren’t,” Manjoo concludes.

Just about every audience gets taken to task in True Enough. The author scolds both Democrats who wrongly believe that Bush lost in Ohio in 2004, and Republicans who think John Kerry was neither a war hero nor an inventive combat strategist. Widely accepted but crackpot beliefs about the Kennedy assassination, global warming, 9/11, and aids are all examined in terms of how people filter out what they wish to be false and embrace, sometimes rabidly, what they wish to be true, even when empirical evidence shows otherwise.

David Cay Johnston covers fiscal and budget matters for CJR’s United States Project. He is a reporter with 46 years of experience, including 13 at The New York Times; a columnist for Tax Analysts; teaches tax and regulatory law at Syracuse University Law School; and is president of Investigative Reporters & Editors (IRE). Follow him on Twitter @DavidCayJ.