An observation on parallel processing in our brain
Today I came across a website which lets you check your typing speed. I am a touch-typist (one who can type without looking at the keyboard) for a long time, and in the five or so tests I took, my speed ranged from 75 to 90 words per minute (78 words per minute, for example, is 432 characters per minute according to them).
The test gives you random sequences of frequently used English words in a line, and an input box to type those. After you type the last but one word, another line appears with the last word of the previous word which you are yet typing, so there is some kind of continuity in the text that you get.
What I noticed while I was typing was something interesting: I was not looking at the word that I was typing. I was always looking one word ahead. And my speed actually reduced when I could not look ahead well in advance, for example after the last word of the current sequence appearing on the screen, when I had to reposition my eyes to look for further words, or when I had to look back at the current word to confirm its spelling.
So my naive way of understanding this is that during touch-typing, while our motor control is working the fingers on a word, our visual and language interpreter is simultaneously processing the next word!
In fact my feeling is that when the words actually form meaningful sentences, our look-ahead is chunks of upto around four words, since we can easily grab and remember such meaningful chunks in one shot. It might actually improve the speed, since the fingers are also programmed somehow to type such chunks in one reflex.