The "Backfire Effect" is well documented in scientific literature.

In a nutshell, it is "when people encounter evidence that should cause them to doubt their beliefs, they reject this evidence, and strengthen their support for their original stance."

https://effectiviology.com/backfire-effect-facts-dont-change-minds/

Or as another author puts it:

"... many times people are motivated to reject information that conflicts with their worldview. Their worldview and identity is conflated with how they see themselves. So they find conflicting information as an actual attack on their self-worth, which makes them engage their defensive biases. When such defensive biases are engaged, people are likely to maintain or even strengthen their previously held beliefs despite being exposed to conflicting information."

http://www.patheos.com/blogs/accordingtomatthew/2016/06/the-psychology-behind-why-we-reject-evidence/#jA87yEeuP7TpjzRH.99

Michael Shermer, of Scientific American, gives this advice on "How to Convince Someone When Facts Fail".

"If corrective facts only make matters worse, what can we do to convince people of the error of their beliefs? From my experience, 1 keep emotions out of the exchange, 2 discuss, don't attack (no ad hominem and no ad Hitlerum), 3 listen carefully and try to articulate the other position accurately, 4 show respect, 5 acknowledge that you understand why someone might hold that opinion, and 6 try to show how changing facts does not necessarily mean changing worldviews. These strategies may not always work to change people's minds, but now that the nation has just been put through a political fact-check wringer, they may help reduce unnecessary divisiveness."

https://www.scientificamerican.com/article/how-to-convince-someone-when-facts-fail/

If you happen to make some sort of breakthrough with friends or family in teaching them the truth about Mormonism, it is then an opportunity to help them navigate through the "Reactions to Change". There will be a "denial" "resistance" and "exploration" phase that they go through. Many of you are working through this process yourselves. There are many applications to these phases. For example, these "reaction to change" phases can be felt in losing one's religion, in grieving over a loved ones death, or dealing with the restructuring of a business.

The reading below will give you insight into how people transition through such phases. Be alert and seize the opportunity with a loved one to teach them the true historicity of the church when the timing is right!

http://changecatalysts.com/blog/?p=152

http://viha.ca/NR/rdonlyres/5369A441-FAA6-47B8-ACAF-B1BA0BEBAF2C/0/understanding_peoples_response_to_change.pdf

Double double down double down down down, breaking up is hard to do.