The chart here is based on standardized tests but reflects exposure to test-taking and education rather than a measure of 'genius' intelligence.
One of the passionate hopes of America's founders was for the availability of education; that anyone could go as far down that road as they were willing and able. The intent has been served well but not uniformly with poverty being the primary hindrance today. In earlier years, race and class were the limiting factors.
In Kenya, tribe determines what opportunities are available for a youngster. My friend Joseph, now in his twenties, is bright, gracious and well-spoken, multilingual, and a handsome fellow, but his education ended at the sixth grade, and his opportunities for employment are limited to day labor. Wrong tribe; he's Mijikenda. If he'd been Kikuku, the ruling tribe/class, he would have gone to college and would be employed in the business or government sector.
Poverty, corrupt government, economic oppression of developing regions, all contribute to inequality. None are chosen circumstances by common folks; all are done to them by others, usually the rich and influential. Yes, poverty is imposed, not chosen. The way out of poverty is discoverable if, and only if, there's a just, equitable environment.
The opportunity for education isn't the same everywhere.
That's the challenge; we can make a difference.
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NOTE (see full article): In recent years, researchers in Africa, Asia and elsewhere have found that people in non-Western cultures often have ideas about intelligence that differ fundamentally from those that have shaped Western intelligence tests. Research on those differences is already providing support for some of the more inclusive Western definitions of intelligence, such as those proposed by APA President Robert J. Sternberg, PhD, of Yale University and Howard Gardner, PhD, of Harvard University's Graduate School of Education (see related article). Eventually, it may also help researchers design new intelligence tests that are sensitive to the values of the cultures in which they are used.