Re-affirming what you already knew

The LA Weekly‘s Harold Meyerson, writing in today’s Washington Post, details a recent series of findings on the public’s perception of news, released by the “Program on International Policy Attitudes”, a presumably uber-wonkish collective of academic research centers and polling firms from Maryland and California.
Here’s the (sadly predictable) one-two punch, a veritable qualification of American egocentrism in statistical form, with relevant facts in bold:
In a series of polls from May through September, the researchers discovered that large minorities of Americans entertained some highly fanciful beliefs about the facts of the Iraqi war. Fully 48 percent of Americans believed that the United States had uncovered evidence demonstrating a close working relationship between Saddam Hussein and al Qaeda. Another 22 percent thought that we had found the weapons of mass destruction in Iraq. And 25 percent said that most people in other countries had backed the U.S. war against Saddam Hussein. Sixty percent of all respondents entertained at least one of these bits of dubious knowledge; 8 percent believed all three.
The researchers then asked where the respondents most commonly went to get their news. The fair and balanced folks at Fox, the survey concludes, were “the news source whose viewers had the most misperceptions.” Eighty percent of Fox viewers believed at least one of these un-facts; 45 percent believed all three. Over at CBS, 71 percent of viewers fell for one of these mistakes, but just 15 percent bought into the full trifecta. And in the daintier precincts of PBS viewers and NPR listeners, just 23 percent adhered to one of these misperceptions, while a scant 4 percent entertained all three.

In other words, odds are that if you get your info from the television, you’re not quite getting reality. While the numbers make painfully obvious the extent to which Fox News viewers are a deluded mess of pre-packaged assumptions, what really stands out is the fact CBS News viewers (with Dan Rather et al hardly considered a mouthpiece of conservative propagation) were still 100 percent more likely than the average American, who may or may not get his or her news from television, newspapers, or water coolers, to be just as deluded about a realistic understanding of events.
True, the PBS viewers seemed to have a better grasp of things than “the average American,” but, well, you knew that already, didn’t you.
What pre-packaged assumptions does Sarah Vowell’s fan base bring to the table?