How Easy is it to Change your Beliefs?

In class today, we watched the video of the twin girls, Lynx and Lamb, and how their mother taught them her white supremacist ways growing up.  As children, the twins worshiped Nazi beliefs and and thought it was important to keep whites separate from other races.  They learned this directly through their mother, and their father was not apart of their life.  As we learned today, at 19 years old, they changed their views, saying that they were accepting of other races.  But how is it possible to believe so strongly in something and then switch to almost the complete opposite?

We discussed that the death threats and hate they received might have forced them into saying they changed their beliefs, but maybe not actually changing.  Or maybe, the hate made them realize that their beliefs caused much discrepancy in society.  Either way, I do believe something, or someone must have influenced them to completely switch their views.

Here's an article on the girls beliefs and updates now:

http://www.mirror.co.uk/news/real-life-stories/nazi-twins-lynx-and-lamb-gaede-941546