Lewis Dartnell, biologist: ‘One of the problems with the modern world is a loss of scarcity in many things’

When Hernán Cortés mounted his final siege of Tenochtitlan in 1521, its Mexica defenders offered little resistance. The diseases the Europeans had brought with them, particularly smallpox, had weakened the region’s inhabitants, who were defenseless against the previously unknown pathogens. Years before, during the seventh century, another dazzling civilization, that of the Muslim Empire, rose up with the assistance of microbes, in its case the bacteria that produced the plague and left the Byzantines and Sassanids weakened. Two empires that had been invincible for centuries were supplanted by other factions who proved better at resisting unexpected outbreaks of epidemic.

In his 2023 book Being Human: How Our Biology Shaped World History (The Bodley Head Ltd), Lewis Dartnell (Taplow, United Kingdom, 44 years old) offers examples that demonstrate the influence of human biology on the evolution of history. After telling of how geology has determined our history in his earlier book Origins, in his latest title, Dartnell explains how infectious disease and genetics led to the appearance of the United Kingdom, Haitian independence and the fall of the Bourbon monarchy in Spain, not to mention how our attraction to drugs has caused wars and the founding of entire countries.

Question. In your book, you suggest that Christianity owes its initial expansion to Cyprian’s plague in the second century, that Islam spread due to the effects of another plague and that the Spanish conquered America to nearly no resistance because of infectious diseases. Aren’t these explanations overly simplified?

Answer. I try very hard to not oversimplify what are obviously very complicated processes happening around the world and across broad swaths of time. Clearly, there’s more than one factor at play. But the point I’m trying to make in the book is that often, we as scientists, as historians, tend to overlook the fundamental nature of us as a species, and the role that it has played alongside economic, sociological or random chance in the outcomes of history.

I wouldn’t argue for a second that biological processes are the only influence or indeed, the most important influence, although in many cases I argue that they are, or that they are the dominant effect. But I think it’s just one thing to add to the mix, to consider. In the case of pandemics and epidemics, and particularly, with the mass depopulation of the Americas, when European explorers first started arriving by sailing ships, I think that it is pretty clear, from the historical and archaeological evidence, that it was a series of enormous pandemics that wiped out a huge fraction of the Indigenous population.

Q. In your book, you talk about the importance of our attraction to drugs, to caffeine, tobacco and alcohol, in the development of history. Is it possible that we now perceive drugs, which we have always used, as something problematic because of our capacity to produce them in industrial amounts? In the past, people couldn’t produce those huge amounts. Maybe smoking a little bit or consuming a little bit of alcohol or other drugs was something that had a very different effect on individuals and society, and could even be beneficial?

A. There’s an interaction between these biological and sociological and technological effects. One of the problems with the modern world is a loss of scarcity in many things that we really had to scrounge around for or spend a long time trying to gather. That includes the ready availability and cheapness of calories in highly sugary drinks that you can buy for next to no money nowadays. That has led to big problems with obesity in much of the world, and diabetes. Some researchers describe this as a disconnect between the environment in which our bodies and psychology evolved and the modern world, where many things are very easy to get. That’s also true of things that we would consider to be drugs, like alcohol, nicotine, opioids.

Q. There are book like yours and those of Yuval Noah Harari that look to impart a global view of humanity, that try to explain our nature using anthropology, geology and biology. Can these books guide us towards improving as a society?

A. I think that often, in science and history, a book can be very focused, very narrow in its outlook, and there’s very much a value to that. But I also think there’s a lot of value in books that take a broader picture, that paint world history in broader strokes. They are necessarily, therefore, a little bit more superficial, a little bit blurrier and more nebulous, but they put things into their context as far as possible.

And in terms of human nature and how we’ve evolved and to what extent we can control our behavior, I argue in the book that biology has been a powerful influence throughout human history. It’s not the only influence, but also, we’re not slaves to our biology. And talking about cognitive biases, they have very, very potent effects. Even researchers who spend their lives studying cognitive biases still fall prey to them. It’s something deep and fundamental in the wiring of our brains. But that doesn’t mean that we can’t get around the problem and there’s a lot of research at the moment into de-biasing or how you can structure committees or groups of people to try to offset the problem of cognitive biases, or how you can do that on an individual level as well. A lot of the time, being aware of the problem is the first step towards solving it.

So I wouldn’t argue that we are slaves to our biology, but also, you don’t want to throw the baby out with the bathwater and pretend that biology and our evolution and our genetics and our anatomy and our psychology have had no impact on human history, because of course it has, and the truth lies somewhere in between those two extremes, and that’s the middle ground that I was trying to explore in the book.

Q. You speak about cognitive biases like our aversion to loss, that the pain of losing $100 is much more intense than the joy of finding $100, and the evolutionary origin of that bias. That makes us more conservative and can explain why many times, the lower and middle classes embrace political stances that don’t benefit them, because they’re more concerned about defending their land from those who come behind them than about demanding more from those above them.

A. Clearly, there’s a lot of influence of psychology and human nature on politics and how people choose the leader they want, but also how candidates and people who want to remain in power try to influence, if not manipulate and control people. In a certain sense, conservatism and not wanting to change things too much makes sense. There’s a phrase in English, “if it ain’t broke don’t fix it.” But I think that mentality can also be abused by the far right or by people taking extreme political views, because power begets power. If you already have power, you’re better able to hold onto that power and diminish other people or keep them under the boot. And we see a lot of that in world history and politics today as well.

Q. Can we learn something from our past and our biology that would give us more happiness? Do you think it’s possible to accept that certain ways of life are better for the majority? Recently, you published that single people, in particular men, have more of a tendency to depression than married people, but wouldn’t it be scandalous to recommend marriage as one would recommend other forms of healthy living?

A. I’m not sure I’ve got some biological secret for happiness or advice for living a better life, because that’s entirely dependent on your personal situation and your circumstances. But as a general principle, and ancient philosophy has been talking about this for a long time: treat others as you expect them to treat you. The golden rule, basically, boils down to that, and we see it being replicated in many different philosophies, many different religions and the formal structures of law that have arisen in states to keep up a peaceful society. Don’t be mean to each other. Seek your own happiness, your own pleasure, your own fulfillment, as long as that doesn’t start impinging on other people’s ability to seek their own happiness. Don’t steal someone else’s happiness or exploit them.

You know, there’s psychological studies into how much you need to earn to be happy. People who are very poor and can’t provide for everything they need are unhappy and as you earn more, your happiness level increases, up to a particular point where each extra euro you earn doesn’t actually bring that much extra happiness. A billionaire isn’t a thousand times happier than a millionaire, you know. You reach the point where you can provide for all your basic necessities as well as some treats and buy yourself a present every now and then or be able to go on a nice holiday, but beyond that, money doesn’t really bring any extra happiness. There’s no secret there.

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