the concept of a great talent developing like you state is proof again that giftedness (of any type) is innate and not developed by pushy parents and hothousing. All the books and documentation I have ever read on giftedness indicate that regardless of the prior educational environment etc, when placed in the right environment a gifted child will fly until they reach the level they would have been at without the restrictions previously imposed.
The only question I have on the entire concept is how then, does learnt underachievement fit into this picture? I'd assume on a surface thought that if you could repair the learnt underachievement mode you would see the same type of acceleration to reach optimum level for that individual. other thoughts on this?
