Recently, Jack made an analogy between reading a chart and reading a music score, also known as sight-reading.
Coincidentally, I just came across this passage from 'Super Sight-Reading Secrets'...
"If we do not open our eyes, we will not see". This is an obvious statement, but think about it for a moment in less literal terms. How many times have you had your eyes open but still missed something important.
To sight-read we must be an open vessel. We must be a sponge - ready to soak up information. The great inhibitor here, you will find, is our own thoughts! Worries, doubts, expectations, fears, distractions... Our mind becomes cluttered or blocked. This weakens its receptive faculties. In other words, the more brain-power we use to think, the less we will have available to take in new information. All of a sudden, we then have a closed vessel.
Clearly, understand, I'm not saying not to think. What I am suggesting is that it may be more than coincidental that "most good sight-readers can't perfect a piece, and most good perfectionists can't sight read". I believe it is good to be able to do both, and therefore good to cultivate two separate brain processes: 1) thought & analysis and 2) gathering data. These might be compared to the modes of a computer.