Wade goes further, however, and challenges the assumption of modern sociologists and anthropologists that human evolution stopped with the development of agriculture ten thousand years ago. He turns this view on its head and asserts that the progression from smaller-scale tribal societies to the large nation states that we know today is due, at least in part, to evolutionary factors. The corollary of this is that tribal systems of society that have survived into the modern era have done so because of genetic constraints on their ability to extend trust and cooperation beyond a small social group that has strong kinship ties.
This inevitably sounds a little racist although Wade is at pains to point out that he doesn't contend that any race is superior to another, only that different races have evolved to adapt to their different environments. I don't completely buy all of Wade's theory and some of the evidence he presents seems scant at best. However, it would help explain why tribal societies such as New Zealand's Maori and Australia's Aborigines find it so difficult to make a successful transition to modern, Westernised societies. Maori aspirations to return to more tribal-based forms of government and resource ownership are understandable if tribalism is built into their DNA. The problem is that tribalism is inconsistent with our modern, democratic, liberal social structures. If we assume that evolution, even at its most agile, will take many hundred of years to adapt to a significant environmental change, then that means the conflict between Western and tribal social structures is likely to be with us for a long time to come.