[giantg2]

I mean, they have isolated tribes that have seen limited outside contact even today. In the absence of outside contact, their culture is not as bland as in your example. Perhaps the formation of culture, religious beliefs, and higher levels of thought is one of the aspects that do make humans special.

As to the IQ tests, they can't ethically run them on uncontacted people. There have been many studies on indigenous people's that include a focus on intelligence. However, a major factor that usually comes up is that the format of standard IQ tests tend to be biased against indigenous people due to things like language issues.