A question regarding pseudoscience believers.

What is the brain doing when it absolutely refuses all evidence against a preconceived notion? I mean this mostly in regard to people who refuse to recognize things like climate change, the benefits and safety of vaccines, and the safety of GMOs.

Many of these folks will check out of a discussion once you ask them to prove their assertions.

Yet, those same folks will jump in to the next discussion with their usual fiction-based claims. The inability to prove their claims does not seem to phase them.

I find this interesting, at least from a brain function basis. I'd love to hear what other folks think about this.

Cheers!