This is a bit off the usual track but I happened to notice that Nick Diaz has written a guest column on Laurie Rogers' blog 'Betrayed: Why public education is failing'.
In the piece, Diaz takes on the stereotyping of 'Asian' students (by which people in the USA mean students whose parents are of Chinese, Korean, Indian, Taiwanese, and Japanese extraction). The stereotype has it that Asian students are 'smarter, can learn math much faster, know "stuff" more deeply, and are much quicker at arriving at answers'. As he quite rightly points out, this is as racist and bigoted as negative discrimination.
However, it is certainly the case that many Asian students do tend to do better in 'math' than other students and Diaz explains this by pointing out that many Asian parents are recent immigrants and are very highly qualified, many of them employed in the USA as engineers, scientists and mathematicians. And, guess what? These families – because these people come with kids! – are usually exceptionally highly motivated and supportive of their children's learning in school.
Culturally, too, according to Diaz, many of these children are trained to be more focused and to engage their brains before they commit to answering questions. Neither are these parents usually given to making statements to the effect that they were 'no good at math' when they were at school.
There's also an interesting discussion on kitchen table math at the moment on the subject of placing maths students by mastery not age.