The question is posed as though this is settled science, when it isn't. Leaving aside causes of difference, the concept of "cognitive ability" is, at the very l

The question is posed as though this is settled science, when it isn't. Leaving aside causes of difference, the concept of "cognitive ability" is, at the very least, fiercely debated as being variously: culturally biased, overly narrow or mechanistic, or unmeasurable. Measurements like IQ or g are only validated by being "correlated with important social outcomes" and "correlated with job performance", uncritically accepting the current society or structure of work as natural or inevitable rather than as products of culture. If "cognitive ability" is restated as "how likely an individual is to succeed and thrive in the dominant culture" it becomes less surprising that there are differences between different "population groups".