The critical age hypothesis has been thoroughly debunked and disproved.It's just not true and sociocultural and individual factors makes the difference in how we learn not specific chronological magical ages.
The danger of any theory that states what a person can or cannot do according to age, gender, race or other variables is two-fold. 1. The individual intending to learn a skill or knowledge, discovering that she is not supposed to be capable, limits her expectations and ends up living down to those expectations and therefore not achieving her potential. 2. The person teaching such an individual, believing in these expectations, gears his teaching toward them consciously or subconsciously, and creates the expected outcome, or even perceives an outcome that is not there. It is a tragedy if an individual wishing to achieve something, ends up not achieving it simply because he won't try, or is undermined in the attempt, because of a theory about his potential. Even if generally true, there are always exceptions.
I know that Daniel Barenboim is an advocate of this method (see the book he co-authored with Edward Said). My experience has been that it certainly helps to have read through a vast amount of repertoire at an early age, although I don't subscribe to the view that this must be done by the age of 20 (a seemingly arbitrary number). Part of my daily routine is to sight-read through new music. When I come to learn a piece that I have read through before (even if only once...but ALL the way through) I am able to learn the notes more quickly and it is more easily committed to memory.I'd be interested to read about the experiences of others. Anyone?
Really? Who says so - except for you? Do you have some literature - preferrably online - that you can refer us to?
Unfortunately the majority of interesting articles and researches on the subject are available only to subscribers of online medical jounrnal but they're available going to a medical library in a big city.