When Corrections Fail

An emerging group of studies examine why people cling to misconceptions and myths and whether fact checking can correct these beliefs.

In the latest study I came across, in Medical Health, the authors ran an experiment to see whether correcting Sarah Palin's infamous "death panel" myth would work.  The answer?  Not for everyone.  Here's the key graph:

The correction reduced belief in death panels and strong opposition to the reform bill among those who view Palin unfavorably and those who view her favorably but have low political knowledge. However, it backfired among politically knowledgeable Palin supporters, who were more likely to believe in death panels and to strongly oppose reform if they received the correction.

Why would more knowledgeable Palin supporters ignore the correction and cling to the myth, especially as less knowledgeable supporters became more accurate?  I can't read the entire study, just the abstract, but I suspect the more knowledgeable supporters were also the more partisan ones.  Simply put, it's harder to change those minds and, indeed, it's likely the correction attempt (as other research has ironically found) actually pushed people to believe Palin even more than they originally did.  And this is scary.