When I read the name "Mark Twain," I mentally replace it with "Samuel Clemens." It's done subconsciously, and sometimes I can read for pages, doing that all along, before I realize there are times when the distinction between the two names serves a purpose.
I used to use a word processing program that worked like that; you would type in a word, make a spelling error, and the program would correct the error while you were still typing. Here's the key point: you could not turn this feature off, and unfortunately, I had made some additions to the spell checker's dictionary including some typos, and was stuck with mis-spelled words forever after, until I finally deleted the whole program in disgust. Of course, you can't do that with your brain. "Sam Clemens" is apparently hardwired in there for the rest of my life.