Pretending we don't know

In the mid 1800s, the tallest people in the world were the Native Americans who lived on the Plains; on the average, perhaps almost an inch taller than the European Americans of the time, and a half-inch taller than Europeans. In the years before the American Revolution, the tallest people in the world were the European settlers in America. It look like, after the revolution, and during the Civil War, alcohol use and diet brought down the average.

Take a look: http://eh.net/XIIICongress/cd/papers/70PrinceSteckel378.pdf

And, a more general look at height:

http://www.newyorker.com/archive/2004/04/05/040405fa_fact?currentPage=3

So what?

We all carry around pictures in our heads of Native Americans as qenetically "squat". There are some, but, in general, turns out not to be the case. We all carry around pictures in our heads of very tall Africans. There are some, but the whole "tribe", the group to which the herders belong, average about 5-9. The mind pictures are just wrong.

So, now you know. There is no doubt: On average, all groups of humans with the same nutrition and same rates of disease, are of equal height. There is one exception, the pygmies, who have an unusual endocrine system. That's it. For all us non-Pygmies, average height is the same -- nutrition and disease held constant. Done. Finished. Settled science.

So, why the memes of squat Indians and tall Africans? Or, rather, why the attachment to the memes, since the reality has been apparent for decades?

Put another way: Why do we pretend we don't know that all populations with the same nutrition and diseases average the same height? This fits into the category of "things we know we pretend we don't know". There are many others; I've put a few on a different page, and will explore them one at a time.

I'm looking for more. Please post any examples you have come across. Prizes, as always, for the best entry. Why don't we make it more interesting: cash prizes for the best entries. Yeah, that's the ticket!!!