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The eminent American geographer Jared Diamond, 75, has spent two decades exploring the question of how human societies have interacted with their environments and resources. His Pulitzer prize-winning Guns, Germs and Steel (1997) discussed the natural advantages available to the cultures that arose on the Eurasian land mass, while Collapse examined how various societies—which may yet include our own—made bad decisions in response to the environmental hands they were dealt. Now, in his newly published The World Until Yesterday, Diamond considers whether the practices derived from the way all humans once lived still provide valuable lessons for the modern world.

Q: Are you arguing that humans have not yet adjusted to the way we now live, emotionally, psychologically and physically?

A: Physically, it’s clear: we have not. Differences to which we have not adjusted include the fact our bodies still have a metabolism appropriate to a binge-and-bust diet, where often you don’t get enough food and then when you get a feast you release lots of insulin and you store the calories as fat. That was fine for the spartan living styles of our past, but now we end up with diabetes. That’s the clearest example of our not being adjusted physically to our current circumstances. As for emotional and psychological lags, there is speculation, but it’s chronically difficult to separate genetic from cultural factors in human attitudes and behaviours. So I personally would not assert anything in those areas. I wouldn’t deny the possibility, I would just say that it’s not established. Continue…