That is not true. Just as Asians are smarter than whites, whites are smarter than blacks. There are several reasons for this, but it is true.
Its not smarts but work ethic. American born Asians are no more successful than American born whites after a generation or two, and Thomas Sowell is no less intelligent than anyone. Anyone! The Chinese that come to our country work harder because they remember Mao, and more recently, Apple factories. American Blacks are by and large stuck in their culture of hedonism and victimhood. American middle class whites are being dumbed down by the NEA and Dept. of Education, etc. The poor just have to try harder.
And Ashkenazi Jews smarter than Asians.
But bringing up reality is not allowed under rules of Political Correctness. We Must Have Equal Outcomes For All Identifiable Groups.