Supposedly, she tested mainly “Britons”, but also “some Chinese” - but the article I read did not enumerate them. There were only about 200 subjects in the actual test, too.
I have to say I am amused that a serious researcher would make the jump to a biological basis rather than cultural after testing only two cultures. I am also curious about the background of the “recent Chinese immigrants”. If there were from Hong Kong, it would be difficult to pretend that they were independent of British cultural influences, ignoring for the moment that it seems a stretch to claim that “white Britons” all have identical cultural backgrounds anyway.
Then again, questions such as these should be addressed in the formal paper, which I located (finally) here. Unfortunately, I am too cheap to pay for it. ;-) I guess I will just have to wait for the movie version to come out on cable ...