Being Human by Lewis Dartnell review – how our biology shaped history | Science and nature books

I blame Yuval Noah Harari. Since the Israeli historian’s bestselling Sapiens: A Brief History of Humankind in 2011, there has been a trend for thick tomes proposing to explain our humanity through one or other lens across deep time. Just this year, we have had books about how human history was shaped by epidemic disease (Jonathan Kennedy’s Pathogenesis), or by climate variation (Peter Frankopan’s The Earth Transformed). Now Lewis Dartnell, author of the brilliant The Knowledge: How to Rebuild Our World from Scratch, and the Harari-adjacent Origins: How the Earth Made Us (on how human history was shaped by the planetary environment), offers a new take on the same old same old. Are there any surprising angles left?

Despite the relentless news of war and mass murder, for one thing, it is good for someone to remind us – as Sverker Johansson also did in his The Dawn of Language – that we are actually unusually peaceful, for apes. (Even free-loving bonobos are much more physically violent to one another.) In Dartnell’s intriguing opening argument, our prehistoric forebears suppressed reactive aggression in favour of “planned proactive aggression”, used only to punish norm-violators, and so constructed a civilisation built on amazing levels of cooperation and reciprocity.

We proceed to examine the influence on history of family attachments (as mediated, it is somewhat simplistically explained, by the hormone oxytocin), including the “prudently plotted marriages” that led to the Habsburgs dominating Europe from the 16th century, or the long demographic reverberations of the mass destruction of young men in war. We consider the historical and geographical distribution of practices of monogamy versus polygamy, the latter being – so the author argues – what humans have a natural “predilection” for, but only if resources allow. “At the time of writing, Elon Musk has a personal net worth of over a quarter of a trillion dollars,” Dartnell observes with a straight face. “With this fortune he could materially support hundreds of thousands of wives, utterly overshadowing the harems of the greatest despots of history.”

Always an interesting and engaging writer, Dartnell avoids the feeling of dutifully ticking off bits of bio-history, and finds fascinating nuggets in familiar stories: the Black Death, for example, killed nearly half the population of London in 1348. In his chapters on disease, he also discusses how the first plan to build a Panama canal – by the Scots in the 1 7th century – was scuppered by malaria and yellow fever, the financial losses thus incurred partly leading to the Act of Union. The threat of contagion, he argues, also “led the colonial powers to operate extractive strategies” in subtropical regions, clinging to coastal ports and shipping out sugar and coffee, rather than settling inland as in more friendly climates such as New Zealand or Canada.

We get a chapter on the social and geopolitical effects of humans wanting to get off their faces on alcohol, or mildly stimulated by tea, coffee and tobacco; and one on how defects or omissions in our DNA may have changed history. Humans’ unusual inability to make their own vitamin C inside the body, for example, led to the lemon juice-quaffing sailors of the Royal Navy having a distinct advantage over the scurvy-ridden French and Spanish at Trafalgar. (Happily, our author does not shrink from calling the navy’s adoption of lemon rations a “sea change”.)

Lest this all smack too much of biological determinism, Dartnell spends a short coda wisely emphasising how human culture and technology have freed us from the raw dictates of the body. Indeed, as he notes, culture has already changed our biology in significant ways, such as when many humans began drinking the milk of domesticated cows 10,000 years ago, selecting for the persistence of the milk-digesting lactase enzyme into adulthood in many populations. Medicine and contraception, meanwhile, liberate modern humans from the meat-grinder of normal evolutionary change.

So are we really essentially the same animals as the early Homo sapiens hunting and gathering on the savannahs? Dartnell thinks so. “The fundamental aspects of what it means to be human – the hardware of our bodies and the software of our minds – haven’t changed.” This is, indeed, the assumption behind evolutionary psychology, which seeks to explain modern human behaviour in terms of what is hypothesised to have been adaptive for our cave-dwelling ancestors. But his mainframe-age metaphor of hardware and software is old hat and inaccurate. We now know that the human brain exhibits substantial neuroplasticity: in other words, the “software” can change the “hardware” it’s running on, as is not the case for any actual computer.

This “software” can also correct itself, which is to say that our thinking is corrigible: a fact that seems obvious in light of the history of disciplines such as mathematics, engineering, or indeed biology itself. Yet Dartnell, despite accepting the facts of cultural evolution, still avers that our “cognitive operating system has not had an update”, and worse, that we can’t do anything about many of its most characteristic errors.

This is the burden of his penultimate chapter about the familiar subject of cognitive biases. Deducing from news reports about violent crime that humans are unusually violent primates, for example, would be a case of “availability bias” – we attach more importance to examples of nastiness we can easily think of (those more “available” to memory) than to the untold examples of people being nice to each other that don’t make the headlines. It is also widely counted as a cognitive bias that humans are “loss averse”, meaning that we weigh potential losses in a bet more heavily than equivalent potential gains – but that should be no surprise to anyone who genuinely can’t afford to lose their shirt, rather than undergraduates in elite western universities playing for toy money in psychology experiments.

Dartnell, though, seems to take his view on loss aversion and the other biases mainly from Daniel Kahneman, who with Amos Tversky first developed the literature on them and wrote them up for a general audience in 2011’s Thinking, Fast and Slow, and who was himself notably pessimistic about the prospects of our learning to escape their clutches in our ordinary reasoning. Dartnell agrees, leaving little hope for the future. “We have seemingly been hardwired,” he writes, “with a number of cognitive biases that impede our ability to take appropriate action to address seemingly distant, gradual and complex challenges such as climate change.”

But “hardwired” is another inexact computing metaphor, and many others believe that becoming aware of cognitive biases can enable us to avoid falling into their traps. There is evidence to suggest that conscious “debiasing” training can reduce susceptibility to biases over the medium term; and the particular scourge of online misinformation designed to appeal to our biases may be vulnerable to interventions in which those tricks are explained to citizens. That, in the form of a recent research initiative by the universities of Cambridge and Bristol, is known as “inoculation science”: one way, perhaps, in which a metaphor from biology can signal a way forward for our culture.

I blame Yuval Noah Harari. Since the Israeli historian’s bestselling Sapiens: A Brief History of Humankind in 2011, there has been a trend for thick tomes proposing to explain our humanity through one or other lens across deep time. Just this year, we have had books about how human history was shaped by epidemic disease (Jonathan Kennedy’s Pathogenesis), or by climate variation (Peter Frankopan’s The Earth Transformed). Now Lewis Dartnell, author of the brilliant The Knowledge: How to Rebuild Our World from Scratch, and the Harari-adjacent Origins: How the Earth Made Us (on how human history was shaped by the planetary environment), offers a new take on the same old same old. Are there any surprising angles left?

Despite the relentless news of war and mass murder, for one thing, it is good for someone to remind us – as Sverker Johansson also did in his The Dawn of Language – that we are actually unusually peaceful, for apes. (Even free-loving bonobos are much more physically violent to one another.) In Dartnell’s intriguing opening argument, our prehistoric forebears suppressed reactive aggression in favour of “planned proactive aggression”, used only to punish norm-violators, and so constructed a civilisation built on amazing levels of cooperation and reciprocity.

We proceed to examine the influence on history of family attachments (as mediated, it is somewhat simplistically explained, by the hormone oxytocin), including the “prudently plotted marriages” that led to the Habsburgs dominating Europe from the 16th century, or the long demographic reverberations of the mass destruction of young men in war. We consider the historical and geographical distribution of practices of monogamy versus polygamy, the latter being – so the author argues – what humans have a natural “predilection” for, but only if resources allow. “At the time of writing, Elon Musk has a personal net worth of over a quarter of a trillion dollars,” Dartnell observes with a straight face. “With this fortune he could materially support hundreds of thousands of wives, utterly overshadowing the harems of the greatest despots of history.”

Always an interesting and engaging writer, Dartnell avoids the feeling of dutifully ticking off bits of bio-history, and finds fascinating nuggets in familiar stories: the Black Death, for example, killed nearly half the population of London in 1348. In his chapters on disease, he also discusses how the first plan to build a Panama canal – by the Scots in the 1 7th century – was scuppered by malaria and yellow fever, the financial losses thus incurred partly leading to the Act of Union. The threat of contagion, he argues, also “led the colonial powers to operate extractive strategies” in subtropical regions, clinging to coastal ports and shipping out sugar and coffee, rather than settling inland as in more friendly climates such as New Zealand or Canada.

We get a chapter on the social and geopolitical effects of humans wanting to get off their faces on alcohol, or mildly stimulated by tea, coffee and tobacco; and one on how defects or omissions in our DNA may have changed history. Humans’ unusual inability to make their own vitamin C inside the body, for example, led to the lemon juice-quaffing sailors of the Royal Navy having a distinct advantage over the scurvy-ridden French and Spanish at Trafalgar. (Happily, our author does not shrink from calling the navy’s adoption of lemon rations a “sea change”.)

Lest this all smack too much of biological determinism, Dartnell spends a short coda wisely emphasising how human culture and technology have freed us from the raw dictates of the body. Indeed, as he notes, culture has already changed our biology in significant ways, such as when many humans began drinking the milk of domesticated cows 10,000 years ago, selecting for the persistence of the milk-digesting lactase enzyme into adulthood in many populations. Medicine and contraception, meanwhile, liberate modern humans from the meat-grinder of normal evolutionary change.

So are we really essentially the same animals as the early Homo sapiens hunting and gathering on the savannahs? Dartnell thinks so. “The fundamental aspects of what it means to be human – the hardware of our bodies and the software of our minds – haven’t changed.” This is, indeed, the assumption behind evolutionary psychology, which seeks to explain modern human behaviour in terms of what is hypothesised to have been adaptive for our cave-dwelling ancestors. But his mainframe-age metaphor of hardware and software is old hat and inaccurate. We now know that the human brain exhibits substantial neuroplasticity: in other words, the “software” can change the “hardware” it’s running on, as is not the case for any actual computer.

This “software” can also correct itself, which is to say that our thinking is corrigible: a fact that seems obvious in light of the history of disciplines such as mathematics, engineering, or indeed biology itself. Yet Dartnell, despite accepting the facts of cultural evolution, still avers that our “cognitive operating system has not had an update”, and worse, that we can’t do anything about many of its most characteristic errors.

This is the burden of his penultimate chapter about the familiar subject of cognitive biases. Deducing from news reports about violent crime that humans are unusually violent primates, for example, would be a case of “availability bias” – we attach more importance to examples of nastiness we can easily think of (those more “available” to memory) than to the untold examples of people being nice to each other that don’t make the headlines. It is also widely counted as a cognitive bias that humans are “loss averse”, meaning that we weigh potential losses in a bet more heavily than equivalent potential gains – but that should be no surprise to anyone who genuinely can’t afford to lose their shirt, rather than undergraduates in elite western universities playing for toy money in psychology experiments.

Dartnell, though, seems to take his view on loss aversion and the other biases mainly from Daniel Kahneman, who with Amos Tversky first developed the literature on them and wrote them up for a general audience in 2011’s Thinking, Fast and Slow, and who was himself notably pessimistic about the prospects of our learning to escape their clutches in our ordinary reasoning. Dartnell agrees, leaving little hope for the future. “We have seemingly been hardwired,” he writes, “with a number of cognitive biases that impede our ability to take appropriate action to address seemingly distant, gradual and complex challenges such as climate change.”

But “hardwired” is another inexact computing metaphor, and many others believe that becoming aware of cognitive biases can enable us to avoid falling into their traps. There is evidence to suggest that conscious “debiasing” training can reduce susceptibility to biases over the medium term; and the particular scourge of online misinformation designed to appeal to our biases may be vulnerable to interventions in which those tricks are explained to citizens. That, in the form of a recent research initiative by the universities of Cambridge and Bristol, is known as “inoculation science”: one way, perhaps, in which a metaphor from biology can signal a way forward for our culture.