For the most part. Cognitive dissonance is the stress that results in believing P and Q are true at the same time, along with a few other scenarios such actions

For the most part. Cognitive dissonance is the stress that results in believing P and Q are true at the same time, along with a few other scenarios such actions contradictory to one's beliefs or being confronted with evidence that is contrary to one of your beliefs (belief disconfirmation paradigm). We then engage dissonance reduction to arbitrate the difference and lessen the stress. One of the easiest methods of which is ignoring or rejecting the conflicting evidence or ignoring the voices that are--literally--causing you mental pain. Socially, belief disconfirmation is arguably the most problematic because it turns rational discourse into something very, very ugly. Instead of persuading people, evidence and debate can further entrench a given belief instead. When certain issues became almost identity and lifestyle statements (climate change denial, the anti-vax movement, GMO hysteria, etc.), contrary evidence is perceived as a personal attack instead of a weighing of scientific evidence to determine fact. Unfortunately, overcoming this isn't easy. And it's made that much harder when people are able to retreat into their preferred echo chambers rather than be forced to directly confront the dissonance.