7
Reuniting Humanity

Our societies are being torn apart. The United States grows ever more politically and socially polarized. Europe has greater support for right-wing nationalist parties than we've seen in a century. Across the globe we see similar patterns.

Social problems on this scale require systems-level solutions. Without an understanding of how the system works, the problems will remain or even lead to new problems. Proximate solutions are like applying duct tape to a leak instead of identifying the leaky pipe and repairing it. As philosopher and writer Robert Pirsig put it,

If a factory is torn down but the rationality which produced it is left standing, then that rationality will simply produce another factory. If a revolution destroys a government, but the systematic patterns of thought that produced that government are left intact, then those patterns will repeat themselves.

The ties that bind us are the very same ties that tear us apart. We are quick to blame greed and selfishness, but these vices have been our companions throughout human history. They are not explanations in themselves and certainly not systems-level explanations.

What destroys the high scales of cooperation evident in a peaceful, prosperous society is lower scales of cooperation. The president who steals from the people to enrich her family; the mid-level manager who gives jobs and other perks to his friends. These temptations are ever present, but when there are not enough jobs to go around, when the world feels more zero-sum, we enter a vicious feedback loop that incentivizes these lower scales of cooperation. When that zero-sum switch is flipped in people's heads then fractures widen, cooperation falls, and the few increasingly benefit at the cost of the many.

In our society, those living paycheck to paycheck are the first to feel the effects of zero-sum circumstances: stagnant wages, lack of quality education, unaffordable health care. These people are like the canaries in the proverbial coal mine. The societal-level forces from which they suffer will eventually hurt us all.

The goal of a successful society should not be just tolerance but harmoniously working together in friendship and comity. Ever higher levels of cooperation is a secular aspiration that aligns with the preachings of the major world religions. To achieve these higher scales of cooperation there must be enough to go around such that fair competition is incentivized. Humans do not necessarily expect perfect equality of outcomes, but they do have a desire for fairness in the competition that leads to those outcomes. In practical terms, this means that when a population's size is increased, often through immigration, we must also invest in infrastructure to ensure there's enough for everyone.

Access to housing, health care, education, and other essentials must keep pace with population growth. Racism, discrimination, nationalism, tribalism, and polarization are not ultimate causes – they are proximate symptoms of the circumstances we find ourselves in when this doesn't happen. This in turn can lead to vicious feedback loops that decrease the circle of those we care about. When the frequency of buses slows down, when car parks are harder to find, we increasingly favor our own families, friends, class, and ethnicities, and are unable to work together for the common good. To see how easily this can happen and the vastly different futures it can create, let's look at Norway and Britain.

Norway versus Britain

Every Norwegian is born with an inheritance of around $250,000. The 5.5 million citizens of Norway start life with access to over $1 trillion through the Norwegian Government Pension Fund Global, also known as Oljefondet or the ‘oil fund’. The oil fund was founded to manage the profits from the vast oil reserves discovered in Norway's part of the North Sea in 1969. The fund has since reinvested profits in the largest companies in the world. This small country, with half the population of Los Angeles County, now owns more than 1.5% of the world's stock market. It is the world's largest sovereign fund. In 2021 alone, returns from just the United States contributed more than $100 billion.

The Norwegian government uses this vast wealth to ensure a high quality of life for all Norwegians. For example, health-care costs are capped at around $200 per year, after which everything is free. Education – elementary, secondary, and university – is free, even for foreign students. Norwegians are a lucky people, but their enviable situation was not entirely down to luck and nor was it inevitable. It was the result of specific decisions. To see the path not taken, we need only look across the North Sea at Great Britain.

Britain also discovered a similar amount of oil on its side of the North Sea at the same time, and has since produced about the same amount of oil as Norway. Britain's population is larger of course, but Britain has also had access to large amounts of coal.

Rather than create a sovereign fund with these resources, which would benefit all, the British government of the time prioritized the profits of private companies and the pockets of a few wealthy people. Rather than plan for the future or consider how to maximize the potential of all its citizens, it took a smaller share of taxes on those profits and used them to bolster political support through tax cuts that primarily benefited the wealthy. Much of this money went into more property for the already rich, inflating the UK housing market and raising the cost of living for everyone else.

So, instead of helping all British citizens, the bulk of Britain's oil profits passed into the hands of oil company shareholders and wealthy citizens. Those closest to the oil benefited from higher salaries and a boost to the local economy, but relative to the value of the oil, these were small spillovers trickling into their bank accounts and the Aberdeen economy. Without strategic investment, the rest of Britain received mere droplets.

And British governments continue to make decisions that favor the few. Today, Britain's poorest are the poorest of all the major countries of Western Europe, with the lowest income share. Norway's are the wealthiest. Norwegians and their descendants will be wealthy for many generations to come. Perhaps forever. Britons today and their descendants will not.

How did this happen?

In 1965 Britain and Norway divided the North Sea shelf by a median line. In September 1969 oil was discovered in British waters. Three months later it was discovered in the Norwegian waters. The discovery of such a vast resource might seem like a boon but it doesn't always lead to increased wealth for the country concerned. Or at least not wealth for all. Sometimes the sudden discovery leads to what's called the resource curse – lower development, greater inequality, increased corruption. The resource makes everything worse than if it were never discovered at all, because people fight over it, the winners use the money to suppress the losers, and the country spirals deeper into poverty. The laws of life allow us to understand these dynamics.

A resource curse happens if a country is not cooperating at a sufficiently high scale to exploit the resources for its citizens’ collective benefit. Typically, when we talk about a resource curse, we have in mind failed states like the tribally diverse and incredibly unequal Democratic Republic of Congo, a massive country in the middle of Africa blessed with diamonds, gold, oil, and rare metals but whose people remain the third poorest in the world. Countries like the UK are not directly comparable with the DRC but they do have a milder version of the resource curse – let's call it a resource hex – with similar causes.

In both cases, there is a small cooperative group based on class and/or ethnicity who do not feel they owe anything to the country as a whole because of the large cultural gap between them and everyone else. And so, they ask the question, can we exploit this resource without involving anyone else? The answer is often yes. For example, an oil company is often a more cooperative group with more shared goals than a large yet divided nation and can work effectively in collaboration with a relatively small number of people within the nation, such as the ruling political party. The returns from the fields can then be used to maintain those people in a position of power at a smaller cost to the oil company than if they were sharing the benefits of the oil with the whole country. In this way a small number of people cooperate at a lower scale to control the resource, making themselves wealthy but leaving the rest of the population poor. Indeed, the few who control the resources are not only wealthier but also now have the means to control the rest of the country and put their own interests first.

Recall from the last chapter that Putin doesn't carry oil fields in his pockets. His power is contingent on cooperating with those who benefit from some share of the resources he controls (such as the oligarchs). In turn, those supporters derive their power and influence from those who get some smaller share from them (their supporters), and so on all the way down to the local policeman, judge, or small-business owner. Historian Rutger Bregman once accused Fox News host Tucker Carlson of being ‘a millionaire funded by billionaires’ (the interview unsurprisingly never made it on air but can still be found on YouTube). I don't know enough about Carlson's income sources to comment on the accuracy of Bregman's claim, but, in general, corrupt cooperative power structures undermining the general public's welfare are often a case of billionaires funding millionaires. And the millionaires in turn funding ordinary people. Ordinary people who are happy to accept a decent income, putting food on their table and a roof over their head, especially given the lack of alternative options in a captured economy. Everyone else not connected to this corrupt network of cooperation? Too bad.

Norway understood the resource curse and actively attempted to avoid it. So far, they have succeeded.

In 1971 Norway laid out the ‘ten oil commandments’ to ensure that this vast new wealth would benefit all Norwegians then and into the future. These commandments served as the beginning of the oil fund, a formal institution – codified norms – around which Norwegians could coordinate and compel one another to ensure the vast wealth was used for the greater good. Norway continued down this path, accumulating so much money that during the 2008 financial crisis the oil fund was able to buy up half a percent of shares in all the companies in the world. When the market recovered, over 60% of the oil fund was now made up of stock market returns. As current CEO of the fund, Nicolai Tangen, eloquently described it, ‘Norway found oil twice, first on the continental shelf and second in capital markets’.

Britain never even got to that point. Long before the 2008 financial crisis and long after, the profits were pilfered away by the few at the expense of the many.

What was the difference between Britain and Norway? An obvious answer is that British politicians lined their own pockets and the pockets of the wealthy well connected and Norwegian politicians did not. But this is a proximate explanation and just moves the question back a step. Why did British politicians act in the interest of the few and Norwegian politicians act in the interest of the many? An ultimate explanation emerges from considering the laws of life.

Britain launched the Industrial Revolution on the back of cheap and available coal. The energy was plentiful but needed innovations and people to access it. Through cultural evolution and cultural-group selection, social and technological infrastructure and cooperation evolved to exploit that available energy. The efficiencies didn't yet exist to exploit the resource with a smaller group so vast numbers of people received education and training that in turn gave them access to the energy and improved their lives. Britain was a society divided by class, but this mass empowerment shook up the old order. The energy unlocked was enough to springboard Britain toward higher scales of cooperation. It used that energy and cooperation to exploit other wealthy but less cooperative targets and created an empire that colonized and dominated the world.

Eurasia was connected by trade routes, such as the Silk Road, swapping technologies and ideas across the more easily traversed east–west latitude. The more climatically and geographically variable and difficult north–south orientation of Africa and the Americas couldn't connect into as effective a collective brain and so was outcompeted. But even within Eurasia, once Britain and later the rest of Europe harnessed a vast new energy source and later industrialized with the power this energy provided, other parts of Eurasia, including China and India, were also outcompeted. From the eighteenth century to the beginning of the twentieth century Britain was a powerhouse. Then the world wars began.

During the Second World War, despite harsh conditions, Britain was an even more united kingdom. The aristocracy had begun to weaken in the late nineteenth century and the classes became more permeable as the children of former aristocrats married wealthy industrialists. In any case, when facing an existential threat, people tend to bind together and corruption decreases as groups are forced to put the best people in power rather than ‘their people’. When you're not at war, there's no harm in your brother-in-law running the armed forces. But when the enemy is at your door, you want someone with competence and experience of warfare in charge – someone who can actually win.

At a proximate psychological level, shared suffering also leads to increased cooperation; it forges strangers into bands of brothers. The suffering of the Second World War led to unprecedented levels of national camaraderie. Old fractures in class and culture gave way to common purpose. Britain was swept by reforms that helped a larger number of people.

Class boundaries, which were already weakening, weakened further as estate taxes (so-called death taxes if you're American, which we'll get to) were raised from 65% in 1940 to a peak of 75% in 1945. In 1942 the Beveridge Report, a social manifesto, laid out a plan for universal social security, free health care, employment benefits, and ultimately the creation of a social welfare state. In 1946, after the war's end, the revolutionary recommendations were implemented, turning Britain into a welfare state with social safety nets and a free National Health Service (NHS) that at the time was the ‘envy of the world’, as is sometimes dubiously claimed today. But the end of the Second World War was also the end of the empire. Britain was deeply in debt and the EROI and availability of coal in its mines was falling. The middle of the twentieth century is remembered by many Brits with fondness. It saw the final throes of an empire in decline. Life was still good, just as it is for many in America today, despite the feeling of unease and impending decline. But collapse is gradual. Britain's energy ceiling was descending. The sun would finally set on the largest empire the world had ever seen.

The end of the British Empire was the beginning of a new Britain. After 1945, the country that had once sent its sons and daughters to the farthest reaches of the empire now saw the sons and daughters of the farthest reaches of the empire come to Britain, escaping difficult circumstances – often created by British interventions – or in search of a better life. Now, in addition to the class divide, groups of people with large cultural distances between them, with psychologies culturally evolved under very different conditions, were living side by side. Such diversity doesn't always spell disaster, but it can be a challenge when it exists under conditions of resource scarcity. The paradox of diversity was at play. It was an opportunity for greatness, but also division. And division won. So what happened?

Fractured countries make bad decisions. When there isn't enough energy and resources for everyone, the scale of cooperation collapses. Just as a malnourished organism becomes weaker and sicker as lower scales of cooperation – cancers and bacteria – dominate, so too does an under-resourced society as class and ethnic divisions dominate. Britain faced diminished resources, inequalities of wealth and class divisions, and quickly rising diversity. It could not meet the challenges of cooperation.

The challenges of integration are also more complex when an already established culture welcomes large numbers of newcomers. When large numbers of European migrants settled in the countries of the New World such as the Americas and Australia, they didn't have to think about integration, they just violently displaced the indigenous populations. As a result, immigrants with culturally similar origins became the majority. But the countries of Europe already had large established cultural-groups and this created a very different dynamic for the small groups of culturally distant migrants arriving from Africa, the Caribbean, and Asia into the UK.

In post-war Britain migrant populations were growing by around 20% per decade. The various migrant communities at the time numbered around 3 million people, just over 5% of the population, but numbers were rising rapidly. The country had not yet forged a new unified multicultural British identity and old economic class lines, which had never really gone away, began strengthening their internal bonds. Without a booming economy or a government willing or able to address the issues, and the feeling that there was not enough to go round, it was too much for the country to handle. Rapid change led to racial conflict in the form of discrimination and violence in communities, political conflict in government, and policies that once again favored the wealthy.

Exemplifying the cultural and political divide, Conservative MP Enoch Powell's infamous 1968 Rivers of Blood speech expressed the zero-sum and diversity concerns of many at the time. As he described it, local communities ‘found their wives unable to obtain hospital beds in childbirth, their children unable to obtain school places, their homes and neighborhoods changed beyond recognition, their plans and prospects for the future defeated’. His speech called for an urgent and immediate halt and reversal of immigration. Even for the time, it was an argument made using incredibly racist and emotive language, and Powell was shunned. But he had tapped into real concerns that were unaddressed and unexpressed by other parties. Many argue that it was Powell's speech and the importance of the issues he expressed that explain the unexpected Conservative Party victory over the incumbent left-leaning Labour Party in the 1970 general election.

In the 1970s and 1980s Britain was racked by race-based violence. Black British rioted against police harassment and South Asian communities were routinely targeted by anti-immigrant groups. This violence was a symptom of a failed integration policy and served to further polarize communities, widen fractures, and encourage people to self-segregate within their own ethnicity – if only for safety. Lower scales of cooperation dominated.

Britain also continued to fall apart along old lines of class and wealth. The estate tax, which peaked in 1969 at 85%, was soon replaced by a weaker inheritance tax with more loopholes that would continue to fall to pre-war levels of 40% in the 1980s, where it remains today.

Democracy and large-scale cooperation are easier when goals and values are shared. When a population agrees on the fundamentals, they can put the best person in power to implement that shared vision. But when there is disagreement on fundamentals, people fight to put their person in power because the opposition represents such different values. For example, if you're in Denmark, until recently an extremely culturally homogeneous society, and you agree on the desirability of universal health care, you can vote for the person who can best implement it. If you are in the United States and are divided on whether universal health care is fundamentally desirable in itself, you will be voting for who will or won't implement it and each group needs to put their person rather than the best person in power.

If wealth inequality is low then more people have a shot at a position of power and a broader range of people in power will ensure policies that benefit more people. But if inequality is large, a small proportion of the wealthy will control political decisions to their benefit.

Britain's political class run quite different cultural software – they speak differently and see the world differently – to the rest of the country. It's a product not just of privilege but of a specific and incredibly effective institutionalized privilege honed over centuries. It's a system that creates a cultural bottleneck and perpetuates the interests of the powerful, who are the product of and in turn feed their own children into the private school pipeline.

(In the UK the term ‘public school’, somewhat confusingly, refers to an elite private school, originally called ‘public’ many centuries ago when such schools first emerged because they had no religious, guild- or other group-based prerequisite for entry. The two most well-known public schools are Eton and Harrow. For ease of understanding of those less familiar with the British terminology, I will refer to the problem as the private school pipeline, but will continue to refer to these specific elite schools as public schools.)

The private school pipeline traditionally starts with prep boarding school at age eight, though sometimes children are sent as young as four. No longer living with their parents or within the broader community, the private school pipeline immediately starts programming children's brains with homogeneous cultural software. From here, most continue to private secondary schools, again, typically living in the school as boarders, limiting outside cultural input. It's a good academic education, highly successful at getting pupils into Britain's two most elite universities, Oxford and Cambridge. Nonetheless, it's remarkable how the mannerisms, accent (remember, accent is an important cue of cultural identity), and ways of thinking of children who attend these schools, differ from those of the rest of the population. Former chancellor and current prime minister Rishi Sunak, a private school student, was once interviewed for a documentary as a twenty-one-year-old. Asked about the diversity of his friends, he said: ‘I have friends who are aristocrats, I have friends who are upper class, I have friends who are working class . . . Well, not working class.’

For many private school pupils, like Sunak, the pipeline ends in positions of power, often in government or finance, always as a result of being part of an exclusive, self-sustaining network of power built on shared experience and world view. As a result, Britain's leaders and many members of the elite are not the best and the brightest, who have fought their way to the top on merit. Rather, the elite and particularly the political class, future prime ministers, finance ministers, heads of newspapers and major public and private corporations are where they are because they were all once friends in the same exclusive playgrounds. Of Britain's fifty-five prime ministers, forty-five went to private schools. Twenty prime ministers went to Eton alone.

Returning to the North Sea in 1969 and the decades that followed, an entrenched class system with a ruling elite far removed from the experiences of ordinary people, personally unaffected by and disinterested in addressing the rising challenges created by significant cultural diversity, meant that when Britain found the treasure, the spoils were never going to be shared by all. That oil boom still temporarily rescued Britain from a decline caused by falling EROI in its failing coal mines, but it was not invested in a way that secured Britain's future and so the decline continues.

In contrast, 1969 Norway had a population that was less than a tenth that of the UK, at under 4 million people, was ethnically homogeneous (remember the paradox of diversity), more economically equal, and already enjoyed greater social mobility. Today, Norway has enjoyed a positive-sum productive cycle. Its energy budget and oil fund continue to benefit all Norwegians, who now have one of the highest levels of income, household wealth, standards of living, and the highest level of social mobility in the world. This last statistic reveals the power of truly equal opportunity.

The differences between the way Britain and Norway handled their oil booms are a result of both path dependence and the specific political decisions made within each country. They are the same dynamics playing out today in an increasingly divided and polarized United States and European Union. Although decline is gradual, the same vicious vines are penetrating every aspect of these and other societies too, tearing people apart. We face the paradox of ever-increasing diversity. The lives of our children will be more difficult than our own, so resolving the paradox becomes evermore urgent but also evermore difficult. So much so that many are afraid to even address the topic for fear that pointing out the elephant in the room might wreck it.

Resolving the paradox of diversity

Some topics are hard for scientists to discuss because they fear their words can be twisted or misused to support hatred, cruelty, and xenophobia. None of us wants our work to make the world worse. Of course not all topics are equally controversial or have the same potential to be exploited for political gain. Knowing the mating behavior of butterflies is very different to identifying the sources of inequality between groups or how to sustainably manage immigration and maintain a harmonious multicultural society.

These topics are so difficult to discuss because they involve real implications for real people – mothers, fathers, children; their livelihoods, freedom, even their safety. Discoveries in these spheres are the equivalent of what engineers call dual-use technologies – technologies that can be used for both peaceful and violent aims.

Nuclear technology gets you power plants. And bombs. Rockets can launch satellites. And warheads. But while there are a lot of stages and resources involved in moving from the theory to developing and launching actual nuclear warheads, in the human and social sciences, mere discoveries and words alone can cause harm. So what should we do?

One approach takes the view that unwelcome hypotheses should not be explored and unwelcome results should be suppressed, denied, and condemned for fear of possible societal harms. Noble lies must be enforced and a fuller discussion never takes place because the topics themselves become taboo. This is an intuitively tempting but dangerous path.

Censoring science is self-defeating. It feeds into the narrative that scientists are not to be trusted because they are suppressing the ‘truth’ in an attempt to protect themselves. That in turn creates a space for less scrupulous scientists or even non-scientists to fill with questionable work, driven by specific social and political agendas rather than the pursuit of truth. These become the sole sources of information on random Google searches, reported in dark corners of the Internet and sometimes by the media. They leave people with a sense that governments, academics, and the elite are not on their side, which in turn feeds into misinformation, conspiracies, and falling institutional trust. Remember, it's not about information, it's about who we think is on our team and whom we think we can trust.

Here's a recent example. Early in the COVID-19 pandemic, the public were told that masks were ineffective if not worn correctly. This was a short-sighted attempt to preserve masks and other then scarce personal protective equipment (PPE) supplies for health-care workers. It was an attempt to influence the public, treating them with a disrespect that was costly when supplies were secured and the messaging then flipped to the importance of wearing masks. And that short-sighted decision prevented people from being told that the masks they should have worn in the first place were proper PPE supplies – N95/FFP2 or N99/FFP3 – the kind of masks physicians working with contagious patients wear and the very same masks people were initially told were ineffective for public use. It was a catastrophic failure of a panicked public health messaging system. How could anyone trust what they were being told? The mistrust created by this expedient messaging will cost lives in the decades to come as people ignore well-evidenced advice on other public health matters.

Being forthright and truthful about even challenging topics is critical to trust in science. If you can't trust scientists, you can't trust science.

And so in a world where public messaging emphasizes that ‘diversity is strength’ or that ‘diversity is destroying us’, depending on which channel you're watching, it is important to acknowledge that, in reality, diversity is a double-edged sword. As the collective brain teaches us, diversity is a fuel for innovation and economic progress as diverse ideas recombine into new innovations. Immigrants have been the super-serum that led to America's super-strength in innovation and technology.

In April 1924 the New York Times declared ‘America of the melting pot comes to end’, a reference to the newly introduced 1924 US Immigration Act that created immigrant ethnic quotas based on national origin. It was a restriction on ‘less favorable’ Europeans – those from southern and eastern Europe. Restrictions, such as the 1882 Chinese Exclusion Act, already reduced migration from non-white parts of the world. America was losing some of its lifeblood.

Recent analyses suggest that the 1924 Act led to a massive 68% baseline decline in indicators of innovation, such as patents, in industries where these migrants, such as Italians and Jews, worked. There was also an overall decline in innovation across other industries – innovations spread and are built upon, and so there were fewer innovations everywhere. To what degree can we generalize results like these from a particular population at a particular time?

The first and perhaps most obvious issue with generalization is that ‘immigrant’ is not a useful category. To ask if immigrants contribute more or less to the economy, commit more or less crime, or are happy or unhappy in their new homes is as crude as asking if citizens contribute more or less to the economy, commit more or less crimes, or are happy or unhappy. When we talk about our ingroup, it's more obvious that we need to disaggregate broad, sweeping claims, be they positive or negative. We need to disaggregate by factors such as the nature of the economy at the time of immigration, the characteristics of both immigrant and local populations such as culture, age, economic conditions, the cause for migration, and level of education.

Humans are a migratory species. Not only have we been marching across the globe for thousands of years, but we have done so back and forth, replacing, mating, cooperating, and fighting with one another on the way. Few populations are guilt-free in replacing a population that was there before. But until the late nineteenth century's age of mass migration, migration was primarily from geographically and culturally closer places. Without large ships and airplanes, we lacked the ability to quickly and cheaply traverse the planet. That is no longer the case.

Today, more people from more culturally distant societies increasingly live side by side. And at a global level, their culturally distant countries of origin are forced to coordinate on global issues as never before. Our world is smaller, but diversity remains. This new form of culturally distant migration and cooperation has enriched our societies but also created new problems.

Remember that diversity has been central to the success of all complex life on earth. Diversity provides the new traits needed to make life evolvable. The recombinatorial power of sex increased evolvability and the speed of genetic evolution. Today, diverse societies recombine diverse cultural traits to empower cultural evolution. Beyond Hawaiian pizzas, businesses started by foreigners, for example, tend to be more profitable and more likely to expand. But there are many barriers to cultural traits meeting and recombining. These are often challenges in communication, coordination, and cooperation – barriers created by diversity itself.

A successful immigration policy requires population-level thinking that considers cultures not as homogeneous blobs (Chinese are like X, Canadians are like Y), but as distributions of different traits. As you know from your own country, state, or city, we can talk about New York culture or British culture, but not everyone is even remotely the same in either of these places. Those differences reflect differences in the relative frequencies of different beliefs, values, and behaviors – not all Americans are laissez-faire about norm-breaking, but they're more laissez-faire than Germans, not all of whom insist that norms be followed. Immigration policies are ultimately policies that enable the host country to sample these different distributions and traits. And there are many ways to do so.

Numbers alone are important. Immigrants from a particular population arriving in small numbers are more likely to integrate with local populations. It's difficult for the only two Norwegian families in a Nova Scotian town to not integrate with locals. But when immigrants arrive in larger numbers, they can represent a cohesive cultural-group, sometimes preserving a fossilized version of the cultures from which they came. An Indian friend of mine was shocked to discover attitudes toward dating in a London Indian community, which seemed to her to be like those of her parents’ generation. She was right: it was members of her parents’ generation who had migrated and preserved the values in the communities she visited.

When immigrants arrive in large numbers with no restrictions, such as during a humanitarian crisis that leads to mass movement of refugees, it is as if the host country were randomly sampling from the whole distribution of their countries of origin. Not everyone will follow the norms common in their own country, but with unrestricted migration, you are more likely to see a fuller representation of the entire distribution – the whole variety of people in the proportions found in a country.

New migrants bring new cultural values, norms, practices, and psychologies that can differ from those of the host country. At a noticeable level, these differences culturally enhance our society, allowing us to enjoy a good taco on Tuesday and a spicy curry on Thursday. Not every Mexican can make a good taco, but the proportion of people with good taco-making skills is higher in Mexico than in the United States. In the United Kingdom, it's nearly impossible to get a good taco – there just aren't enough Mexican migrants. But immigrants bring more than just food.

Some valued cultural traits might be present at higher proportions than in the local population – valuing hard work, education, or entrepreneurship. But other less-desirable cultural traits can also be present at higher rates than in the local population – reduced tax compliance, less support for gender equality, reduced belief in the rule of law. Even with smaller cultural differences, these migrant communities shape societies.

The present regional differences in the United States can be traced to their founding immigrant populations. The Puritans, for example, brought an emphasis on education to New England. The Scotch-Irish brought an honor culture of politeness, avoidance of offending others, maintaining reputation, and condemning ‘improper conduct’ to the Deep South. This trend has continued, with cultures remixing and finding more and less compatible previously arrived traits. For example, migrants from agricultural societies who used plowing rather than hoeing are, even in the second generation, more likely to agree with statements such as ‘When jobs are scarce, men should have more right to a job than women’ and ‘Men make better political leaders’. It's not just beliefs. Fewer women from these groups are in the workforce.

It should be emphasized that these are always overall average effects that mask the distributions. There are many New Englanders even of Puritan ancestry who don't value education, Southerners even of Scotch-Irish ancestry who don't possess an honor culture, and those from plow-based agricultural societies who have a highly developed sense of gender equality.

New methods we've developed for measuring these cultural differences between groups based not on averages but entire distributions of cultural traits are revealing. One metric, the cultural fixation index (CFst), gives a score between 0 (identical cultural trait distribution) and 1 (completely non-overlapping cultural trait distribution). Using the United States as a comparison culture, for example, we find that most countries range from 0 to 0.3 in their cultural distance from the United States, suggesting large overlaps between all peoples in the world. But those cultural distances combined with that range predict many broader cultural and psychological gaps in personality, values, corruption, and even the tendency to donate blood or return a lost wallet. The following figure shows how distant different countries are from the United States. The height of the bars are just labels, but greater distances are found as you move further to the right.

Cultural distance from the United States calculated using CFst on the World Values Survey. Source: Muthukrishna, et al. (2020).

Unsurprisingly, the most culturally close countries to the US are Canada, Australia, New Zealand, and Great Britain. Singapore is culturally close to the US as well, a result of many Singaporeans receiving an American education – what you might call a cultural download. The most culturally distant countries are Egypt, Yemen, Jordan, Azerbaijan, Pakistan, and Indonesia. We also find large cultural distances within countries – in the figure, the bigger the polygon, the larger the cultural distance. Note that similar cultural distance from the United States does not suggest cultural closeness to one another. Britain and Bolivia are similarly geographically distant from the US but not geographically close to one another. Similarly, Colombia and Bulgaria are similarly culturally distant from the US but not culturally close to one another.

Non-metric multidimensional scaling (NMDS) plot of cultural distances between regions in China, India, USA, and EU, with a larger shape revealing a larger cultural distance.

The United States is highly diverse but regionally much more similar than the other largest populations – China, India, and the European Union. The diversity in the United States is not primarily regional.

And so new migrants bring with them cultural values both desirable and less desirable. In other experimental work, we find Canadians who have lived in countries with more corruption lead experimental groups to also behave in more corrupt ways, presumably because they have internalized or been exposed to similar behaviors. The entire group becomes more corrupt because those who take the bribery option end up with higher pay-offs and the others don't want to be seen as gullible. We find no such effect based purely on ancestry – the tendency to offer or take bribes is not a trait intrinsic to Canadians as far as we could tell. But such traits can spread.

In research on the spread of the use of tax loopholes, a large predictor of use is not only whether you would benefit from the loophole but whether you know others who use such loopholes and get away with it. The actual probability of getting caught by tax authorities like His Majesty's Revenue and Customs (HMRC) in the United Kingdom or the Internal Revenue Service (IRS) in the United States is unknown, and so many societies rely on norms of compliance perhaps supported by unknown risk of punishment rather than actual punishment of tax violations.

In almost every country, most people do not commit crimes and as such, most immigrants also do not commit crimes. But with no selective migration, migrants will possess cultural traits at a rate comparable to those found in their countries of origin. Some populations have higher levels of educational attainment matching the educational attitudes found in their countries of origin. Some populations have higher rates of violence matching their countries of origin. These can also be quite specific, such as sexual crimes being associated with gender attitudes which see women as less equal in their countries of origin. Much trumpeted and troublesome statistics are that there have been hundreds of bombings in Sweden over the last few years, primarily in foreign-born or second-generation migrant communities from regions with higher rates of violence. Similarly, around 50% of rapes and attempted rapes in Sweden are committed by foreign-born residents, most from countries with corresponding negative attitudes to gender equality and higher rates of female harassment than those found in much of Europe. These trends for foreign-born crime more generally are also found in Norway, Denmark, Finland, and Switzerland. This pattern is not unique to Europe. In Australia, for example, Sudanese migrants, many of whom experienced high rates of violence in Sudan are over-represented in crime statistics, including violent crime.

This is an emotionally heated and polarizing set of statistics that is often ignored on the left and exaggerated on the right. Even mentioning these statistics can reinforce existing prejudices and biases. Moreover, these statistics can lead to self-reinforcing feedback loops – if the migrant group is perceived to be problematic, this can lead to increases in violence and anti-immigrant targeting of the group, further widening the cultural fissures. It is also important to remember that we are talking about distributions – most migrants do not commit crimes nor necessarily excel in education, but the rates of both may match rates found in cultures of origin. The point here is not about specific crimes but that immigration is a process of sampling cultural traits and assimilating both the desirable and the undesirable. And culture isn't just about identity or country of origin – it is the beliefs and values in your head and how you behave. Those can also be shaped by education or wealth. For example, foreign-born Germans commit crime at a higher rate than other Germans living in Germany, but rates are similar to native-born Germans with comparable education and wealth. Education too is a form of cultural difference.

What should we do with all this information? Diversity may be double-edged, but it is too powerful a sword to put aside.

The first thing is to recognize the importance of the sampling strategy you choose. Are you selecting migrants based on education, on wealth, on language, or at random? How do these correlate with different cultural traits?

The choices are not always easy. One example of sampling at random is when there is mass migration by refugees fleeing war or famine (as was the case of Syrian migrants to Europe and Sudanese migrants to Australia). When a million displaced people are at your border, economic framing is the wrong choice. Mass migration is a humanitarian crisis that we navigate as best we can. But we must recognize that it is ultimately sampling at random from all the cultural traits present in migrants’ countries of origin with the heartbreaking additional trauma of forced displacement.

Samples taken from illegal migrants, whatever their circumstances, correlate with the willingness, motivation, and ability to overcome the barriers to entering a country. Perhaps those traits include high tolerance for risk and willingness to start new enterprises, but perhaps also a willingness to break the law. Within the United States, where economic integration is high, immigrants commit fewer crimes than local communities, but illegal immigrants commit more crimes than legal immigrants.

Legal migration offers the host country better opportunities for selection on the basis of cultural traits, including education. For example, countries can develop policies that select for cultural traits associated with greater personal success for migrants and greater economic benefits for the host country. Encouraging high-skilled immigration into industries where home-grown skills are lacking is a good general heuristic. Countries such as the US, Canada, UK, and Australia have benefited from migrants with relevant training for industries such as science, engineering, and health care. The US tech sector is a particularly notable success story, using high-skilled immigration to meet the growing need for engineers.

Once people migrate, ideally through a selective policy, the next step is to introduce policies of optimal acculturation. Both acculturation and integration sometimes have negative connotations based on the fear that people will be forced to change, they will lose their sense of identity, or that the process involves value judgements about which culture is better. Optimal acculturation focuses on cultural differences that impede communication and coordination, much as one might want to do when two companies merge. The aim is to close cultural gaps to the benefit of both migrants and locals, and for cultural cohesion. It involves greater understanding and communication on both sides, migrant and local. Closing the cultural gap is essential to strengthening harmony against a falling energy ceiling, tightening the bonds between us during times of economic growth and recession.

Optimal acculturation

Ineffective immigration and multicultural policies are bad for both immigrants and existing populations. Poor policies lead to immigrants not doing as well as they perhaps expect, and when there are limits on migration, they displace other migrants who may have had more success to the benefit of themselves and the host country.

If the country has a strong social welfare system, it means that locals and migrants who contribute more are subsidizing locals and migrants who contribute less or even cost the system more than they contribute. Further, support for the welfare state itself is threatened by lower contributions and more fractured societies.

Getting immigration and multicultural policies right is worth it. As Lee Kuan Yew, Singapore's founder, is said to have told political scientist Joseph Nye,

China could draw on a talent pool of 1.3 billion people, but the United States could draw on the world's seven billion people and recombine them in a diverse culture that exudes creativity in a way that ethnic Han nationalism cannot.

Lee would know all about how difficult resolving the paradox of diversity can be but also the large rewards from achieving it. He was a controversial leader, but under his stewardship Singapore knitted together multiple cultures, languages, religions, and classes of largely Hindu Indians, Muslim Malay, and Buddhist, Taoist, and Christian Chinese into one of the most successful countries on earth. Remember, big, friendly, interconnected populations become the best and brightest. It should be no surprise that Singapore is at the top of many tables for education, low crime, business, anti-corruption, and more.

So how do we get to a successful multicultural society that allows us to resolve the paradox of diversity and benefit from its rewards? Let's begin by evaluating three common multicultural strategies in terms of the degrees to which they achieve optimal acculturation. I want to emphasize that every country has different policies that continue to change over time and these categories are merely broad generalizations about their overall philosophy.

No hyphen model

In 2018 France won the FIFA World Cup. Its twenty-three-member men's football squad was made up of fourteen players of African ancestry, prompting South African-born host of America's The Daily Show, Trevor Noah, to joke that Africa had won the world cup. ‘Look at those guys,’ he quipped, ‘You don't get that tan by hanging out in the South of France.’

Diplomats don't normally pick fights with comedians, but French Ambassador to the United States, Gérard Araud, was outraged. He chided Noah, claiming that the joke denied the Frenchness of the players and fed into far-right talking points, legitimizing ‘the ideology which claims whiteness as the only definition of being French’. Conveying the French ideal, he wrote that,

France is indeed a cosmopolitan country, but every citizen is part of the French identity and together they belong to the nation of France . . . Unlike in the United States of America, France does not refer to its citizens based on their race, religion, or origin. To us, there is no hyphenated identity, roots are an individual reality.

No Algerian-French or German-French. No Muslim-French or Christian-French. Just French. France, at least on paper, is prototypical of what we might call the no hyphen model of multiculturalism.

France has a long history of this assimilationist model. Even as a brutal colonial power, its official policy was that those who adopted the French language and French culture were truly French and part of the Republic. The morality of not recognizing different ethnic groups as subcategories is up for debate, but pragmatically if such high levels of integration could be achieved, it would resolve the paradox of diversity. But this is a big challenge, and in practice, France often falls far short of the ideal.

Take North Africa for example, where the French no hyphen assimilationist model led to policies that suppressed local culture and traditions. Violence, including mass killings, torture, and forced relocation, was used to enforce policies and suppress dissent while exploiting the wealth of nations. Although North Africans absorbed the French language and some French norms, the unequal status of those from North Africa and those from France affect present-day group relations and the experiences of North African migrants in France. The colonial experience of French culture no doubt made a pathway to integration easier, and, indeed, many North African migrants continue to contribute to present-day French culture. But cultural and socioeconomic gaps remain and discrimination, prejudice, and the legacy of the colonial era have led to a North African identity and subculture within France. The present reality, in other words, is far from the no hyphen ideal.

A no hyphen model can be achieved, but it requires either small numbers of migrants from any particular origin such that cultural enclaves are unlikely to form, culturally close migrants (including socioeconomic cultural closeness) who can more easily integrate, or selective migration for those who are motivated to integrate. Ideally, it requires all three conditions.

It also requires local populations to welcome newcomers to social gatherings and other forms of bonding critical to cultural transmission. Typically, this requires sufficient resources and people to share things in common as a basis for friendship. These many conditions are often not met. Migrants often don't assimilate to French values and norms as measured by everything from beliefs and behaviors to jobs and job types, and the composition of friendship groups. These interpersonal dynamics are overlaid against France's ongoing struggle between a no hyphen model and inequality between groups, on the one hand, and the human tendency to cooperate and affiliate with similar others at a scale that maximizes personal benefit, on the other. The symptoms of this struggle manifest in everything from rife discrimination and lack of integration to public discourse on the wearing of a hijab.

At the other extreme of the no hyphen model is an approach where there is little to no encouragement for migrants to integrate at all, an approach that encourages communities to coexist as separate cooperative groups. This model is sometimes called a mosaic model (or the less alliterative ‘salad bowl’).