Is this because I wrote it down, or I'm seeing it in my own handwriting, thus personalizing it?
It would be an interesting test to have textbooks and instruction manuals customized into your own handwriting... There are web sites like this one who will turn your handwriting into a font for a nominal fee. Once you have the font on your PC, all you have to do is apply the font as your default.
Would your attention span for reading be increased by even a small percentage by having the text in your own handwriting? Or would this trick work only briefly, and then the bonus would diminish as your mind realized it was being bamboozled?