In order to avoid cognitive dissonance you have a number of choices. Primarily: selective exposure and/or confirmation bias. Researchers from a number of US universities are now attempting to quantify these phenomena, looking at how we seek validation as opposed to correctness.
The researchers found that people are about twice as likely to select information that supports their own point of view (67 percent) as to consider an opposing idea (33 percent). Certain individuals, those with close-minded personalities, are even more reluctant to expose themselves to differing perspectives […] They will opt for the information that corresponds to their views nearly 75 percent of the time.
The researchers also found, not surprisingly, that people are more resistant to new points of view when their own ideas are associated with political, religious or ethical values.
[…] Perhaps more surprisingly, people who have little confidence in their own beliefs are less likely to expose themselves to contrary views than people who are very confident in their own ideas.
As an author of the study (pdf) suggests, maybe those who fall victim to selective exposure and the confirmation bias do so because the new information “might prevent them from living the lives they’re living”. Sounds almost like an evolutionary response to prevent dissonance.