There is definitely something cultural to being able to remember sequences of numbers in reverse: I am sure societies that don't have a concept of numbers would have a much harder time with it... As for the geometric shapes, remember the example of the africans building 2d models of the 3d drawing. It seems likely that there is a cultural component to seeing abstract shapes. The Kanji example was perhaps bad - OK, think about recognising kaukasian and chinese faces. They are just faces, no? But somehow it is hard for many kaukasians to tell chinese people apart, and presumably vice versa. I don't think that is genetic, it is trained. It makes me think twice about the cultural aspects of recognising "geometric shapes".

For completeness I want to mention that I don't doubt that IQ tests measure something. Like if they predict success in the military or whatever, they are probably right, ie the IQ63 guy from Ethopia (from another post) would probably have a much harder time in the US military than the IQ 100 American. It is just not clear that it measures "intelligence" per se. And perhaps for the Ethopian military, the results would be reversed. Ie try putting up "surviving in the Saharah without water" as an IQ test.