milo, i think every culture has great thinkers, and thinking is not culturally connected.
some people can think in 3d (and they can look at a image of a 3d thing, and rotate it in their head, and know what it looks like turned to left (or right, or upside down)
some people are quickly able to see patterns (humans excell at seeing patterns!) and are able to replicate them.
as a child, i was able to memorize passages with out understanding the words, or meaning of the passage.
these skills/gifts/what ever you call them, are signs of intelegence.
they are not culturally dependent.
there are folks (and we have mostly likely somewher in our life seen evidence of this) who have trouble making a pattern as simple as a checkerboard (--and their attempts to lay a set of floor tiles in a checkboard pattern are flawed.) others, can see and replicate complex patterns or even create new patterns, with ease.
these abilities can be one way to measure inteligence.
(one of the test i was required to perform in a 4 hour IQ test involved seeing (but then having the image removed) and being asked to recreate the same image (they became increasing complex)--all created with wooden tile of squared, diamonds, triangles and rectangles.
those who can't lay a checkerboard tile floor, would 'fail this test' --and people from other cultures, could 'pass' and they wouldn't need to know anything about our culture, or we about their culture to have this happen.
the word/culture values test (that pass for IQ test) are not true measure of inteligence, but measures of how well adjusted a person to the values the test is measuring.