"So, primitive hunter-gatherers who have never been inside a classroom score as high on geometry as American children who are being "educated" at $10,000 per head per year."
But US students educated at 10,000/year can read and write whereas the "primitive" hunters cannot - er, well, never mind.
I speculate that this concept could be turned around, using pictures like this to reinforce intuitive ideas of geometric concepts before the formalities are introduced. Such as work on boosting the 67% picture choosing scores to something much higher using colloquial explanations of the differences.
Do you believe that 67% of government school education children in the country can read and write?