Apparently, the more confident you are about your own beliefs, the more uninformed you may actually be.
From the article...
A striking recent example was a study done in the year 2000, led by James Kuklinski of the University of Illinois at Urbana-Champaign. He led an influential experiment in which more than 1,000 Illinois residents were asked questions about welfare -- the percentage of the federal budget spent on welfare, the number of people enrolled in the program, the percentage of enrollees who are black, and the average payout. More than half indicated that they were confident that their answers were correct -- but in fact only 3 percent of the people got more than half of the questions right. Perhaps more disturbingly, the ones who were the most confident they were right were by and large the ones who knew the least about the topic. (Most of these participants expressed views that suggested a strong antiwelfare bias.)
Studies by other researchers have observed similar phenomena when addressing education, health care reform, immigration, affirmative action, gun control, and other issues that tend to attract strong partisan opinion. Kuklinski calls this sort of response the "I know I'm right" syndrome, and considers it a "potentially formidable problem" in a democratic system. "It implies not only that most people will resist correcting their factual beliefs," he wrote, "but also that the very people who most need to correct them will be least likely to do so."