Diamond on biological differences

On Friday afternoon, as has happened a few times, I was asked if I had read Jared Diamond’s Guns, Germs and Steel. How could an evolutionary analysis of development accommodate Diamond’s thesis?

As Diamond frames his book in the prologue, Guns, Germs and Steel provides an environmental explanation of human development. Diamond states that you could summarise his book with the following sentence:

History followed different courses for different peoples because of differences among peoples’ environments, not because of biological differences among peoples themselves.

The interesting thing about this characterisation of his book is the discussion over the following pages where Diamond counters those who seek to develop genetic explanations of development. While taking aim at those who suggest there is an inherent superiority to people from industrialised nations (which is fair enough), Diamond utilises an evolutionary argument himself.

Diamond suggests, based on his observations of people in New Guinea, that modern stone-age people are on average probably more intelligent than industrialised people. For example, he suggests they have much better skills such as forming a mental map of unfamiliar surroundings.

Diamond suggests two reasons for his impression that New Guineans are smarter than Westerners. One is environmental, with Diamond believing that, compared to the passive television based environment of Westerners, New Guinean children are exposed to a far more stimulating environment. The second is that New Guineans are more likely to have been selected for intelligence.

Comparing the environments of Westerners and New Guineans, Diamond submits that while most Western children survive to adulthood and reproduce regardless of their genes (or intelligence), New Guineans live in societies where population is too small for the epidemic diseases to evolve. Mortality came from murder, tribal warfare, accidents or failure to meet subsistence needs. In New Guinea, intelligent people are more likely than less intelligent people to escape those causes of high mortality.

This suggests that Diamond is not averse to arguments about the selective pressures in different societies. In the same way, I consider an approach to development that considers how humans have evolved is not inconsistent with most of Diamond’s work. As global populations were exposed, as Diamond catalogues, to a range of different environments and opportunities, they followed different developmental paths, and those developmental paths in turn could have subjected populations to varying selective pressures.

This issue would then be what those selective pressures are, how populations may have changed and whether this affected economic development. Diamond only dealt with this issue in the prologue, so it is not clear whether Diamond considers changes in the frequency of genes and traits could have played a role in development, but it would seem not.

As for my perspective, I find Diamond’s hypothesis useful in an evolutionary analysis of development. The environmental differences identified by Diamond would place different selective pressures on human populations, and as those populations change, that could in turn feed back into their environment. Take agriculture. Those populations who had access to the right plants, animals and geographic features are those that developed agriculture - an environmental argument. But within those populations, people with certain traits would have been more likely to take up the agricultural lifestyle and of those who did, those with certain traits more successful at it. A feedback loop would occur, with the environment shaping the people and vice versa. This is not, as Diamond frames it, a question of nature or nature. It is about the relationship between the two.