"East Asians have a relative strength in spatial ability"
Begging the question. Even assuming that the tests of spatial ability are properly measuring it--which may well be the case--we have no reason to believe that that is a cause of, rather than consequence of, the symbolic nature of Kanji.
The whole point is that we do not have tools, given a respect for basic human rights and unpredictability and complexity of human societies, to perform the experiments that would allow us to tease out cause from effect in these socio-economic, ethnic and gender based differences.
There is absolutely no question that people of African-American descent perform worse on average on standardized tests. THAT is not the question.
The question is WHY. Simply saying, "Well, we haven't managed to change it, so it's biological," is totally illogical. Same goes for "girls can't do math", "white guys can't dance", "boys aren't verbal", etc. You need to be able to show a causative relationship, not just a correlation.
Randomized controlled trials that would control for the variables in question from conception to adulthood (well past 26) would require the controlling of thousands of individuals for three decades. If you can get funding and approval for that, let me know.
I'm in!
