I’m in the middle of Steven Pinker’s How the Mind Works. He talks about experiments in which subjects are shown letters in random orientations, and have to figure out whether the letters are mirror-flipped or not. What was found was that people have to mentally rotate the letters they see, so that they’re right-side-up, at which point they can tell whether the letters are mirror-reversed or not. This rotation takes time.
I wonder if similar work has been done with respect to words and text. It seems that when I’m reading text with a lot of typos, or 1337-speak, or poor punctuation, or inappropriate homonyms (e.g., “who’s” when it should say “whose”), it takes me longer to read than to read text with proper sentence structure, punctuation, and spelling. I wonder whether this is just an illusion, or whether it actually takes more mental work to read the text as written and translate it into proper English.