The Secret of Our Success: A Review


The title, The Secret of Our Success, may lead this book be mistaken for a self-help manual, to be shelved alongside 12 Rules for Life and The Seven Habits of Highly Successful People. But this is a far more serious book with a far larger canvas. And a much better book.

Joe Henrich, an anthropologist by training, is professor of human evolutionary biology at Harvard. His purpose is to ask why humans are the ecologically dominant species on earth. So The Secret of Our Success is not a book about economics. In fact the only references to economics in the index are two – to economic games, such as the ultimatum game, and to economic norms, as resolution of such games. But this is a book which invites us to change the way we think about economics.

Humans are amazing. We can land a man on the moon. We can fly 500 people to Australia in less than 24 hours. We can create nuclear explosions that will destroy a city, or if we prefer, supply that city with electricity for 50 years. We can build computers that fit in our pockets, send messages, calculate the square root of any number, navigate you to your destination, and on which you can read any one of millions of novels.

And yet our physical achievements are unimpressive. Many other mammals can knock us down with ease. We cannot, unaided, rise more than 6 foot above the ground. Most cats can outrun us. And our children can survive only after they have been dependent on their parents for years.

The obvious answer is that we have big brains and so we are smart. But Henrich claims that we’re not that smart. He devotes an early chapter to the subject of lost European explorers. He describes Franklin’s expedition in 1845 to find the north-west passage, which ended with the death of the captain and his crew of 100. The ship had food and other provisions to last for years, a well-stocked library, fuel, insulation and desalinators, but the ship became locked in ice, and the crew was unable to survive in the Arctic conditions. And yet these are conditions in which other humans, native tribes have been able to live for thousands of years. But Franklin’s crew was unable to work out how to do so. Burke and Wills were the first Europeans to cross Australia, but died on the return journey. King, the third member of their expedition, lived but only because he successfully made contact with an aboriginal tribe which looked after him until a rescue party arrived.

And that is the key point. Franklin, Burke and Wills were intelligent and resourceful. But they could not survive in unfamiliar circumstances without the collective intelligence which other groups of humans had developed but they lacked. Cultural evolution over long periods of time has established knowledge which enable indigenous people to manage life in the cold of northern Canada and the dry interior of Australia. And without access to this knowledge, Franklin, Burke and Wills died.

Humans can send rockets to the moon, exploit nuclear fission, and build smartphones. But no individual knows how to do any of these things. Thousands of people, working together, do. As the primate specialist Mike Thomasello has observed, you never see two chimpanzees carrying a log together. Adam Smith began the Wealth of Nations with a description of the pin factory, in which specialisation by task created a business unit far more productive than any individual pin-maker could achieve.

But the ‘progress of opulence’ Smith described was only getting started. Contemporary manufacturing capabilities extend well beyond pins. Today we can build an Airbus 380, a flying machine almost as long as a football pitch, with engines built in one country, wings in another, and put together an extraordinary logistics operation which brings all the parts together for final assembly in Toulouse. Another logistics operation allows the plane to be used for daily flights to Sydney. The ability to engage in large-scale cooperative activity is what makes humans as a species unique. It is the secret of our success as a species. It is certainly the secret of the productivity of modern developed economies.

This capability is a challenge to economists whose focus is on the rational optimising individual. A challenge reinforced by Henrich’s observation that other species are better at rational optimisation than us. Pigeons quickly learn to solve the Monty Hall problem, which continues to bemuse most humans. And they can fly, which we can’t, but we don’t need to because we can build Airbuses, which they can’t. Chimpanzees know how to play the ultimatum game as ‘rational’ agents; they make derisory offers which are never refused. But we know how to carry pieces of timber together. And humans have managed to solve much more complicated cooperative tasks, tasks specific to historical and geographical contexts. The folk in Toulouse who assemble Airbuses could not survive in the outback of Australia, and the people who do survive there have no idea how to assemble an Airbus.

Henrich describes an exercise in which both toddlers and young chimpanzees were subject to a battery of cognitive tests. On problems like counting, spatial awareness and understanding of causality – if this then that – there is little difference between the performance of very young children and very young monkeys. But there is a dramatic contrast in the capacity for social learning – the ability to learn from the actions and movements of other people as distinct from our own observation of the environment around us. And that capacity for social learning, he argues, is why there is really no difference between the measured intelligence of adult and young chimpanzees, but a large difference when the same comparisons is made for (most) humans.

Henrich emphasises three different kinds of learning: individual learning, the process by which infants pick up cues from the world around them; social learning, in which they pick up cues from their parents and teachers; and cultural learning, the accumulated knowledge which enables almost everyone to be able to make fire. But in different ways: you and I can do it in our houses with the aid of a box of matches, but are incapable of doing it in the wild; isolated tribes know how to do it in the wild and have no idea how to do it in London.

Evolutionary arguments in social science have still not fully recovered from the setback they received when the eugenics movement was discredited by the racial policies of the Nazis. Even recently, E O Wilson, the biologist who was led the study of evolution by the social life of insects such as ants, found himself greeted by protesters. Henrich’s narrative is punctuated by frequent paragraphs designed to ward off accusations of racism.

Ideas about group selection, which had been present in the work of Darwin and many successors, lost favour in three decades after the Second World War with the discovery of the human genome and the careful exposition of the mathematics of evolutionary processes. The unit of natural selection was the gene. And agents would incur costs to cooperate with others only in proportion to their genetic relationship. ‘We expect to find that no one is prepared to sacrifice his life for any single person but that everyone will sacrifice it when he can thereby save more than two brothers, or four half-brothers, or eight first cousins’, wrote W D Hamilton, one of the founders of mathematical evolutionary biology, in 1964.

But we now recognise multiple levels of evolution, and Henrich describes the interacting roles of natural selection, group selection, and cultural selection. These mechanisms of evolution map into his trilogy of individual learning, social learning, and cultural learning, and these three types of mechanism interact in a process of coevolution.

New Zealand provides some of the best dairying country in the world, and a majority of the population of New Zealand is lactose tolerant – able to digest milk as adults – although most of the population of the world is not. There is a complex process at work here. The prevalence of lactose tolerance in New Zealand is observed, not because such tolerance is advantageous in New Zealand, although it is. Most New Zealanders are lactose tolerant because they are descended from Western Europeans, and most Western Europeans are lactose tolerant. Lactose tolerance and the practice of dairy farming developed together in Western Europe in a process of coevolution, which occurred over centuries in an area in which climate conditions were favourable to this type of agriculture.

When Western Europeans settled in New Zealand, they did so in large part because it provided  a climate similar to but somewhat better than the one to which they were accustomed. And they discovered land well adapted to dairy farming. So they imported their cows and their farming practices. And modern New Zealanders encourage their children to drink milk. Natural selection at the level of the gene, group selection by groups of immigrants, and cultural selection of agricultural techniques, operated together. Biological learning – genetic predisposition towards tolerance, social learning – ‘drink your milk up children’ – and cultural learning – the practice of efficient dairying, interacted. Most New Zealanders of Polynesian descent are not lactose tolerant, although we can expect that this will change as intermarriage and other mechanisms of natural selection take effect.

So the secret of our success is the collective intelligence produced by genetic, social and cultural coevolution. The product of that collective intelligence is very different in different cultures, as Henrich’s examples of the lost Western explorers illustrate so clearly. No individual knows how to build that Airbus, but tens of thousands of people taken together do. And that observation raises larger questions for economists and economics. How does the extraordinary coordinated operation that takes millions of parts, builds them into subassemblies, and transports the whole variety of pieces from wings to engines to seats, until they all miraculously fit together when a final assembly operation in Toulouse creates a finished aeroplane, but one customised to the purchaser, come about?

The economist’s conventional taxonomy of markets and hierarchies only scratches the surface of this achievement. An Airbus certainly isn’t put together at the end of a grand auction which buyers and sellers joust together, offering to buy and sell aircraft parts until a competitive equilibrium is reached. Nor – this is closer to reality but still a long way from it – is there some Big Boss who decides to build an Airbus and invents the first steps in a hierarchy of principal-agent incentive contracts which are ultimately reversed as the necessary pieces are passed up the hierarchy. Perhaps the better way of describing the process is as the assembly of a collection of capabilities, culminating in the capability which is the collection of skills necessary to organise such an elaborate production.

The larger question is how such capabilities are developed in the first place. It is little more than a hundred years since the Wright brothers completed the first manned flight. The accumulation of knowledge since then has enabled us to fly supersonically, put men on the moon, and build huge passenger-jet aircraft. Small bits of that knowledge can be described as intellectual property, but the bulk of this collective intelligence is a communal property available to everyone. The incremental processes of small modification and invention, tested by selection, which have developed that shared knowledge is why we are as productive as we are.

As I put Henrich’s book down, I was reminded of Gary Becker’s claim that ‘all human behavior can be regarded as involving participants who maximize their utility from a stable set of preferences and accumulate an optimal amount of information and other inputs in a variety of markets. If this argument is correct, the economic approach provides a unified framework for understanding behavior that has long been sought by and eluded Bentham, Comte, Marx, and others’. The extraordinary combination of naïveté and hubris on display is far too characteristic of a modern economic approach to issues of policy.

I prefer the style and the humility of Henrich’s concluding paragraph. ‘To move forward in our quest to better understand human life, we need to embrace a new kind of evolutionary science, one that focuses on the rich interaction and co-evolution of psychology, culture, biology, history, and genes. The scientific road is largely untravelled, and no doubt many obstacles and pitfalls lie ahead, but it promises an exciting journey into unexplored intellectual territories, as we seek to understand a new kind of animal.’

You can buy The Secret of Our Success here.

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