@ Val — Thanks, these are interesting points.

@ kcab — Ok, I was misremembering. In any case, Arthur Jensen wrote http://en.wikiquote.org/wiki/Arthur_Jensen#The_g_factor:_The_science_of_mental_ability_.281998.29 "The most critical tool for scholastic learning beyond the primary grades— reading comprehension—is probably the most highly g-loaded attainment in the course of elementary education."

Advising for gifted children available at Cognito Mentoring.