Wired for Culture: Origins of the Human Social Mind (9 page)

We think of Europe as one of the most crisscrossed, settled, and resettled areas of the planet, and so genes should be thoroughly mixed. But even in Europe knowing a person’s genetic profile can often place them within a hundred or so miles of their birthplace, or if not them, their parents’ birthplace. In fact, plotting measures of genetic similarity among people of European ancestry produces a pattern that resembles the shape of Europe. Clusters on the lower left of the grid are from Spain and Portugal, the United Kingdom samples fall in the upper left, with French samples in between, those from Scandinavia and Germany fill the upper right, and samples from Romania, Bulgaria, and the nations of the former Yugoslavia fill in the lower right.

If we measure large numbers of neutral genetic markers from populations around the entire world and then use them to form clusters, we get back groupings that bear a striking resemblance to what have conventionally been recognized as the major divisions of people on the planet: Europeans and Western Asians, Africans, people from the Americas, Eastern Asians, and Australasians. But this is merely a statistical statement and should not be used to say that there are “races” of people with abrupt or clear genetic boundaries between them—there are not. All of humanity shares the same genes and we can all happily and successfully interbreed. And contrary to the pronouncements of some well-known public figures right up until recently, there is not a shred of evidence that human groups differ in the genetic factors that cause intelligence or even in general cognitive abilities. But the existence of distinct clusters of genetic similarity and dissimilarity seen all over the world tell us that we are a species that has made a habit of maintaining our differences.

CULTURES SLOW THE FLOW OF INFORMATION
FROM “OUTSIDE”

THE ENGLISH
famously lost an important battle to William, Duke of Normandy, at Hastings in the year 1066. William the Conqueror’s reign and the Norman conquest of England that he brought with him carried with it many elements of the French language. French was even the official language at the English court for around three hundred years, and the effects can still be heard in the words of government like “parliament,” “legislature,” “executive,” “judicial,” “bureaucracy,” and of course “government
.
” But the English language, like its people, stubbornly refused to be overrun. It is true that English today boasts a large vocabulary because about half of its words derive from the Romance or Latinate languages, of which French is one. But the other half proudly shows off its Germanic ancestry, and its core vocabulary words are more likely to be of Germanic than French origin. For example, English speakers say “good” (from German
gut
) not
bon
, “mother” and “father” (from German
mutter
and
vater
) not
m
è
re
and
p
è
re
, and “milk” (from the German
milch
), not
lait
. On the other hand, this large mixed vocabulary gives English a freedom and variety of expression other languages will not enjoy. English speakers sitting down to dinner (from the French
dîner
) can refer to “beef” (from the French
boeu
f
) or “cow” from the German
kuh
. And there is pork and swine, mutton and sheep.

It can be revealing of our sentiments to see how cultures treat instances of traits coming in from “outside.” When cultural traits are transmitted vertically from parents to offspring or teachers to the young, no one takes much notice. But traits acquired from other cultures are far more likely to be regarded with suspicion or even indignation, the home population being seen as an unwilling and impotent victim. The French are convinced their language is now suffering the reverse of what happened to English after William the Conqueror. France, in a spasm of linguistic isolationism, now devotes a government ministry to slowing or banning what is portrayed as an overwhelming march of English and American words, customs, and phrases into the French language and culture. Phrases like
le weekend
or “fast food” just won’t do for this ministry. The result is that while the other nations of the world work away on their computers, the French resolutely sit at their
ordinateur
(and the Swedes at their
dator
). The British are alert and often piqued at what they perceive to be Americanisms invading their language. But one review of the English language by the
Oxford English Dictionary
researchers revealed that English had admitted at least 90,000 new “meanings” (being what a word refers to) over the past century, but only 5 percent were acquired from outside British culture. If change is an enemy, it resides within, but it would appear that cultures like to shoot messengers.

So sensitive are cultures to their use of language that George Bernard Shaw once purportedly remarked that Britain and America are “two nations divided by a common language.” Some attribute the quote to Oscar Wilde or even Winston Churchill, but regardless of who said it, it is not hard to find examples. Older British hotel staff might still ask visiting American guests what time they would like to be “knocked up” in the morning. An American family hosting a British visitor might be disappointed to hear their guest describing their house as “homely,” which to Americans means unprepossessing. American visitors can elicit similar reactions in their British hosts when they comment on a person’s trousers by saying “nice pants” (suggesting to the uneasy Britons that the Americans have somehow gained knowledge of their underwear). Or as so often happens in a pub, an American guest might request two drinks at the bar by holding up two fingers to the bartender—a dangerous gesture in the UK at best, but plainly rude when it is the back of your hand that faces someone.

These anecdotal accounts can be placed upon a firmer footing. If cultures routinely swap traits with other cultures, they should tend to share the most traits with those of their nearest geographical neighbors. If, on the other hand, cultures are more closed than this and tend to acquire their traits from previous generations, then they should tend to have the traits of the cultures from which they descend; that is, of their ancestral culture. Geography and ancestry are normally correlated, but measures that can separate the two show that traits related to hunting and fishing practices, family structure and kinship, are often handed down over generations rather than acquired from neighbors. Techniques and patterns of Iranian rugs and even Native American longhouse designs tend to be handed down from generation to generation rather than acquired from neighbors.

Cultures can and do acquire ideas and skills from those nearby, but neighboring societies often differ far more at a cultural level than might be expected because they resist such influences—just think of Québec and the rest of Canada, or the outpouring of cultural diversity that occurred when the Soviet Union collapsed: in Central Asia alone, Turkmenistan, Uzbekistan, Kazakhstan, Chechnya, Tajikistan, Moldova, Kyrgyzstan, and Dagestan reappeared, all differentiated by culture, ethnicity, and language. Even under the influence of close geographical neighbors, or oppressive regimes, cultures can remain stable and coherent units. Cultural evolution is not the free fair exchange of ideas it could be.

CULTURE AND THE MISSING YEARS

IF THE
genetic changes that defined our species were in place by 160,000–200,000 years ago, and social learning has been the force we think, why then did it take until 60,000–70,000 years ago before we were able to leave Africa and successfully colonize the rest of the globe? These are sometimes called the missing years for modern humans, and so staggering is the space of time for a species not to make use of its full capabilities that many authors suggest there was a very late genetic change, perhaps even as late as 40,000 years ago, that finally made us “fully” human. Forty thousand years ago is identified as the likely candidate time period because this was the time of a great flowering of human cultural innovations, including ornamentation and painting, but also tools and other aspects of what archaeologists call “material culture,” or the things we made that leave a trace in the archaeological record—for example, fine hand axes, small and complicated blades, art and decoration and arrowheads.

But such a late genetic change is unlikely since it implies that the change occurred after modern humans had left Africa. Then to explain how all modern humans came to have the same capabilities requires awkward scenarios in which, for example, some genetically superior group arises perhaps 40,000 years ago in Europe, or Asia Minor, or Australia, or New Guinea, and then resettles the entire world; or worse, that they don’t, implying some groups are inferior to others. Another suggestion is that the same mysterious late genetic change occurred repeatedly in separate groups, at all the different places in the world we were to be found at that time. Neither of these scenarios is correct. The genetic evidence shows that we all trace our ancestry back to African populations that lived probably 60,000 to 80,000 years ago, not to some more recently inhabited part of the world where a supposedly superior group arose.

Instead, our missing years might be the product of a phenomenon known as
random drift
that can cause small populations to lose information, and thereby slowed the pace of cultural evolution early in our history. In small populations, chance or random events from one generation to the next can strongly influence whether something or someone survives. This can slow the rate at which they can adapt if the effects of drift oppose useful changes. Its consequences can be worked out precisely using mathematical arguments, but the idea readily surrenders to a verbal one. Imagine you live in a small island tribe of around fifty people and there are five among you who carry a gene that improves celestial navigational skills. I do not suggest that there are genes for celestial navigation, but if you have ever tried to use the nighttime stars to navigate, as the Polynesians did to dramatic effect in occupying the Pacific, you will recognize that any genetic differences among people that made some better at this than others would have been strongly favored. Suppose now that all five of these people set out in a large boat on a seagoing journey, and during that journey a terrible storm blows up and they all drown at sea. In one stroke of bad luck this valuable gene has been driven to extinction, at least in this society.

But now, instead of fifty people in the tribe, let’s consider there are five hundred, and that as before 10 percent of the people or fifty carry this special gene. It would take a particularly extreme spell of bad luck—or perhaps a very big boat—for all fifty of these people to find themselves in the same boat on the same stormy night. There is no reason to restrict the argument to genes. In a small group, ideas, technologies, and skills can easily be lost owing to the effects of random drift. The reasons could be bad luck, or perhaps there are not enough models for others to imitate, key people might die, there are fewer people to come up with new ideas, and fewer people to correct others’ mistakes. We must also bear in mind that learning by watching and imitation is difficult, and so knowledge and skills are prone to drifting away from their starting points. Most of the time when you try to imitate someone doing something complicated, you get the task or the behavior wrong the first time around: just watch someone fly-fishing or hitting a golf ball and then try to repeat the action. Now imagine someone is trying to learn that same skill by watching
you
.

In his book
Guns, Germs, and Steel
, Jared Diamond describes how isolation and small population sizes can even cause societies to lose traits directly related to survival and prosperity. Diamond tells us how when Europeans first landed on Tasmania in the eighteenth century, they sent back descriptions of a culture that had lost many of the technologies originally taken there from the Australian mainland. People had reached Tasmania by 34,000 years ago but became cut off from mainland Australia when sea levels began to rise around 24,000 years ago. By the time the European explorers arrived tens of thousands of years later, the Tasmanians had no bone tools, no fishhooks, no hafted tools or spears, and no spear throwers. They had even lost their appetite for fish! Having lost bone tools they could not sew clothes. They had resorted—as did the Tierra del Fuegians of South America—to smearing their bodies with seal or other marine mammal body fat to preserve their own body heat.

If you think these examples say more about Fuegians or Tasmanians than they do about you, ask yourself if you could make fire without matches, or tell the difference between the edible and inedible plants in your local wood or forest. Dependence of knowledge and learning on the size of the group is surprising to us because we enjoy the benefits of societies that write things down, or draw pictures, or take photographs. Even so, we still see the value of groups today as when we get together to play card or other games. Often no one individual knows all the rules, but by pooling everyone’s slightly different portions of the knowledge the game can usually be reconstructed.

DEMOGRAPHY AND THE “RULE OF TWO”

IT IS
not enough that our species could use social learning to acquire the skills to move into most of the environments on the planet. And neither is it enough to say that we acquired the psychological dispositions to protect and keep intact our cultural survival vehicles. For our species to occupy the entire globe, our populations would have had to be expanding. Had they not been, we would either have stayed put, or when we moved to new lands we would have vacated the territory we left behind. But this is not what happened: the combination of human culture and social learning has meant we have repeatedly produced excess numbers of people, enough in fact to occupy the entire world. Indeed, human beings are distinguished in the biological world as having broken a hallowed rule of demography that we can call the “rule of two,” and to have done so over long periods of time.