As the parent of exceptionally able children, and a school doctor, I must point out that this is not my personal or my professional experience.
I attend reviews in several schools, and have written medical reports for countless statutory assessments, and I strongly believe that high ability is not, per se, a cause for serious behavioural disturbance. I would accept that it can combine with other factors - environmental or internal - to cause difficulties. The imposition of mostly "whole-class teaching" would constitute an environmental factor, I suspect.
As a parent I have had great joy from bringing up my children with high ability. They have presented no more problem than any other child, but sometimes the content of my dilemmas has been unusual - such as, what books to provide for a six-year-old with a reading age of 13-plus, or whether a year with children two years older will be the best option. This is one good reason for the existence of support groups such as the National Association for Gifted Children, because one isn't likely to be able to mull this over with parents in the same position at the school gate.
These children deserve an appropriately challenging education not because they are potential troublemakers, but simply, like all children, they are entitled to schooling which will develop their abilities.
Exceptionally able children come in all shapes and sizes, and it is not helpful to perpetuate old-fashioned myths. The need is rather for more research on how to educate these children best - research which would be likely to benefit the majority of children.
DR P M M MILLS
19 Grecian Road