10% of our Brain myth

I caught my sister mediating last night, and I asked her what she was doing. She told me that mediation was the easiest way to access the areas of the brain we don't normally use, and she was training her mind to be able to read other people's minds. All I could do was shake my head, and she told me that it must be working because she "heard" me think that I thought she was crazy. But where did she even get this idea from?
Apparently it originated by a misquote of Albert Einstein, and has been publicized very heavily since, especially with the movie "Lucy". Evidence to support the myth is nonexistent. But there is plenty of evidence disproving it. Neurologically, there have been countless of tested to prove the activity of the brain, and even the side effects of removing small sections of the brain. They all showed that if any part is altered, through a stroke or brain tissue removal, they have devastating effects on the person, regardless of where it occurs in the brain. Evolutionarily speaking, we evolve larger brains for a reason, and I'm pretty sure it wasn't the have 90% of it silent for our entire lives. But when I tried to explain this to her, she hushed me because I was breaking her concentration.