This question already has an answer here:
Some people form a belief and become absolutely resistant to any contrary evidence or reasoning. Even in the face of overwhelming evidence, these people stick to their beliefs. I'm pretty sure this is something that has been investigated by cognitive sciences, and I'd like to know what this phenomenon is called as I'd like to learn more about it.
So, what is the mechanism of this denial-of-evidence called?
I recently came to the conclusion that a lot of people who hold onto conspiracies and the like show similar behaviors to religious fanatics. The way these conspiracy-believers argue and the way they react when confronted with critique or even evidence seems to be similar, no matter what conspiracy-topic it's about (with varying degrees of fanaticism, of course; some can still be reached with reason while others are so deep into their belief-system that they cannot be reached any longer). I find this strangely fascinating and would like to understand the "mechanics" of this phenomenon.