Wired for Culture: Origins of the Human Social Mind (5 page)

Even so, if we think all of this means we are not in thrall to many of our cultural ideas, or even controlled by them, we would be wrong. This is because the analogy between memes and biological brain parasites breaks down for most aspects of culture. We are not in general locked into a life-dinner “arms race” with culture, continually evolving to avoid its clutches while it evolves to get better at infecting us for its gain at our expense. Where a parasite, suicide meme, or even a silly tune harms its host or at best does it no good, the rules, beliefs, ideas, and customs that make a culture have, on balance, advanced our interests. We have been far better off with than without them. And sure enough, when we look at the products of culture, the list of things that have promoted our survival and well-being is long—tools, spears, arrows, baskets, shelters, methods of hunting and fishing, or even just how to tie a knot in a rope. E. O. Wilson once said that people are “just DNA’s way of making more DNA,” and what will emerge throughout the rest of this book is that culture—that software collection of ideas, routines, rituals, and behaviors written into our brains—is the most successful way there has ever been of making more people.

But this raises a point of great and fundamental importance to our psychology: we have every reason to suspect that our culture’s hold on us is far stronger than that which manipulative parasites or exploitative memes can exact from their hosts. They are things we seek to avoid, and most of us do, even if not always successfully. But we will have been selected to embrace many aspects of our cultures, even allowing them a degree of mind control, because they became the most potent trait we could acquire. We have good reason to expect that human children have been shaped by natural selection to absorb information about their culture from their parents and other teachers, rather than rely on instincts coded by genes. We have to be that way for the simple reason that we rely more than any other species on the accumulated knowledge of our ancestors to survive and prosper. It is true this makes our children vulnerable to people and ideas that wittingly or unwittingly take advantage of them. And yet, we cannot escape the fact that you—for the most part—embrace your culture because it is your ticket into the future, just as your genes—for the most part—embrace your body because it is their ticket into the future.

If we accept that our cultures have promoted our genetic interests throughout our history, then the arbitrariness of our particular cultural affiliation tells us something else: it reminds us that our particular culture is not for us, but for our genes. You could just as easily have received a different set of cultural ideas from the ones you happen to carry around in your mind. This is a shorthand way of saying that our dispositions for culture evolved because they were those that led to the greatest reproductive success. Were our particular culture for us, we might have a choice in the matter of which one we join and which one we might die for. Maybe we have a taste for fish, or are drawn to hot climates. But few of us ever do have a choice because we seem programmed willingly to accept the culture of our birth, and Scotland’s soccer fans—not to mention the resilience of culturally defined emotions such as xenophobia and racism to attempts to stamp them out—tell us it is hard to adjust to a new cultural environment once the one we were born into has been installed into our minds.

Still, it is not enough merely to say that culture has been successful. It would have collapsed long ago as an evolutionary gamble if people could have achieved success without succumbing to its control. In return for this allegiance to culture, we are entitled to expect that it will have evolved ruthlessly to promote our existence. Realizing that both of these things can be true is a large part of what this book is about. Chapter 1 is about the prosperity that culture has delivered. Chapter 2 helps us to understand how the mind control that culture exerts on us could have evolved and why it is so important to our societies—an idea we will revisit again in Chapter 4. Chapter 3 is about how culture has farmed or domesticated our many talents.

CHAPTER 1

The Occupation of the World

That humans invented a new kind of phenotype or body, the
cultural survival vehicle
, to propel them around the world

THE RISE OF THE GENUS
HOMO

T
WENTY-EIGHT THOUSAND YEARS
ago, in a large cave at the southern end of Gibraltar, what might have been the last of the Neanderthals died. They hadn’t been pushed there by the encroaching Ice Age that would reach its peak in Europe about 8,000–10,000 years later. Instead, this was their last redoubt, having been displaced, outcompeted, or simply killed by modern humans who had relentlessly marched all over Europe following their arrival some 12,000–15,000 years earlier. It must have been a time of terror, confusion, and despair for the Neanderthals, whom we now know were over 99.5 percent identical in the sequences of their DNA to us, and who had been living in Europe for perhaps 300,000 years. The new modern people would have been cleverer and more inventive, more adaptable, more mobile, and certainly more successful. They would have carried a baffling and frightening array of technologies, and they would have been good at using them. Their standard of living would have fallen far short of ours, but to the Neanderthals, life in human society must have seemed luxurious and privileged. And to make matters worse, these modern humans might even have shown up singing and playing instruments, dancing, wearing sewn clothes, producing art and making carved figures. It would have been like a scene from a science fiction story of a people confronted by a superior alien race, except it was really happening.

With the extinction of the Neanderthals, just a single species of human—modern humans or
Homo sapiens
—remained in a lineage that had spawned six or more previous species. That lineage, the genus
Homo
or humans, arose about 2.25 million years ago on the plains of Central–East Africa in the form of
Homo habilis
or “handy man,” a small but upright ape whose fossil was discovered by Mary and Louis Leakey in Tanzania in the early 1960s (a recently discovered fossil of a species possibly even older than
H. habilis
has been attributed to the
Homo
lineage and named
Homo gautengenis
). Another lineage of upright apes, the Australopithecines, was alive at the same time. Its most famous member is “Lucy,” or
Australopithecus afarensis
, who lived perhaps 3.2 million years ago in and around modern-day Ethiopia. The Australopithecines had smaller brains and were more primitive than
Homo
, and they would later go extinct, possibly the first casualty of the newly evolving human lineage. Both of these lineages of upright apes—
Homo
and the Australopithecines—trace their ancestry back through even earlier species, and eventually back to a chimpanzeelike common ancestor that lived perhaps 6–8 million years ago.

Homo habilis
clearly bore the marks of its ancestry to the apes, but not long after its appearance, sometime around 1.8 to 2 million years ago, a species called
Homo erectus
appeared. It stood fully upright and might have reached a height of five and a half to six feet tall. If you were to meet one you would recognize it as different from us, but you would also see in it the first real indicators of what we would become. Gone were the small brains, short legs, and long arms of the Australopithecines and early
Homo
species, and in came the bigger brains, long legs, and shorter torsos of so-called humans. Around 800,000 years ago, possibly even earlier, some
Homo erectus
populations made their way out of Africa and inhabited parts of Eurasia. Other
Homo erectus
, known by some archaeologists as
Homo ergaster
, remained in Africa. It was these
H. ergaster
populations that by about 800,000 years ago had evolved into a species known as
Homo antecessor
, which in turn gave rise by 500,000 years ago to a species called
Homo
heidelbergensis
.

There might have been one or two other premodern or archaic humans around this time with names such as
Homo helmei
and
Homo rhodesiensis
, but there seems to be a growing view that they can all be included within
H. heidelbergensis
. It is difficult to be precise and opinions vary, but
H. heidelbergensis
seems to have spawned two new lineages. One of these lineages would eventually lead to the Neanderthals and a species whose identity was only just confirmed in 2010, and which is known by just a single tooth and a finger bone. Originally designated
X-woman
, this species is now being called
Homo denisovan
after the Denisova Cave of southern Siberia where the tooth and finger bone were found. Dating of the cave suggests these people were still living as recently as 30,000 years ago, meaning they overlapped with both Neanderthals and modern humans. Remarkably, it has been possible to extract ancient DNA from the tooth and finger bone, and this reveals the Denisovans to have been a sister species to the Neanderthals.

The second lineage is the one that would eventually lead through one or more premodern archaic humans to us. Our species, so-called fully modern humans, finally emerged from their archaic
Homo sapiens
ancestors only around 160,000–200,000 years ago. This might have occurred in East Africa, as has long been believed, or possibly in southern Africa, as hinted at by modern genome studies. But wherever we arose, we are still a very young species by comparison to most, like one of those birth-of-a-star events beloved of astronomers. Given our recent appearance, it is not surprising that the first modern humans would have been almost indistinguishable from us today, and one of them brought up in modern society would not be out of place. They had large brains, possibly even somewhat larger than our own, and somewhat bigger bodies; but compared to Neanderthals they were lighter, less robustly built, had high foreheads, and lacked the protruding brow that characterizes that species.

Homo sapiens
was distinguished from other
Homo
species, including premodern humans, not just by their appearance but also by showing the first glimmerings of symbolic thinking in the form of art and adornment. It was a revolutionary development in our minds because now one object could stand for another or even for a set of ideas, and a symbol’s presence acted to communicate those ideas to other people. Until recently, the earliest evidence for symbolic thinking came from Blombos Cave in Western Cape Province, South Africa where pierced and painted seashells thought perhaps to be early examples of jewelry, and even an engraved stone, have been found and dated to around 75,000 years ago. But excavations not far away at Pinnacle Point in Western Cape Province have now found little beads of red ochre pigment that might be 160,000 years old. Evidence such as this is notoriously difficult to interpret, but these small fragments of ochre are clearly and deliberately scratched as if to make a powder, suggesting that these modern humans were painting something; though whether it was their bodies, caves, or other objects isn’t known.

Some modern human groups might have moved north through the great continent of Africa around 120,000 years ago in what was the first “out of Africa” migration. Fossil evidence suggests that some of these people turned eastward and crossed the narrow Bab al-Mandab Strait at the southern end of the Red Sea and into present-day Saudi Arabia. Others continued northward, eventually making their way into the Levant in an area of what is present-day Israel, where archaeological digs show they might have lived alongside Neanderthals. Opinion is divided, but modern humans apparently didn’t last in the Levant, or if they did, their numbers were so small that no fossil or archaeological traces remain after around 75,000 years ago. But then back in Africa sometime around 80,000 years ago, maybe somewhat later, the flickerings of symbolic thinking and communication that had characterized our species from its origins gave way to a flowering of culture. Abstract and realistic art appeared, jewelry in the form of threaded shell beads, teeth, ivory and ostrich shells, ochre and tattoos; small stone tools appeared in the form of blades and burins; bone, antler, and ivory artifacts were made; there were tools for grinding and pounding; and improved hunting and trapping technology, including spear throwers, and possibly even bows, and nets.

So imaginative had our species become, archaeologists define the appearance of so-called modern humans—in comparison to the “archaic” modern humans who immediately preceded us—by our artifacts, or the things we made, as much as by any real changes to our appearance. Genetic evidence points to a time around 60,000 years ago, maybe somewhat earlier, maybe somewhat later (the dates cannot be more precise than this), when populations of these modern humans left Africa for a second time. They followed coastal routes across the Arabian Peninsula and into India, thereby acquiring the name “beachcombers.” Modern human populations eventually made their way to Indonesia and Papua New Guinea, and then by 45,000 to 50,000 years ago into Australia. The speed with which they got there after having left Africa leads some to believe that these first occupiers might have been descendants of the earlier out of Africa migration into the Middle East, but no one knows for sure. Other modern human migrations up through the Middle East eventually took people into Eurasia, where they replaced the resident
Homo erectus
and X-woman/Denisovan
species, and into Europe by around 40,000 to 45,000 years ago, where by 28,000 years ago they had replaced the Neanderthals.

No one can be sure whether modern humans simply outcompeted these other
Homo
species or whether they moved in and killed them off in direct confrontations. As with so many questions like this, the truth is almost certainly some of each. But startling recent evidence reveals that not all of our contacts with these people would have been warlike; some might even have been amorous. A few of the Neanderthal skeletons and the sole Denisovan fragments come from individuals who died recently enough in our past to fall within the range of time that it is possible to extract ancient DNA from their bones. A careful comparison of the complete genomes of these Neanderthals with those of modern humans, and a similar comparison between modern humans and the new Denisovan species, suggests that we might have interbred with both of them. If we did, some might find it reassuring to note that the evidence indicates the contact was limited: modern humans share around 4 percent of their genome with Neanderthals and Denisovans. This is to say that against the background of our genomes being approximately 99 percent or more similar to these species anyway—reflecting our recent divergence from a common ancestor—there are regions whose precise genetic signature gives them away as being even more recently shared.

But there is a further twist. Current evidence indicates that interbreeding with these archaic
Homo
species occurred in two brief episodes. One episode happened possibly in the Near or Middle East shortly after a subset of modern humans left Africa. The second occurred further to the east, probably near to where the Denisovan fossils were found, and only in ancestors of modern-day Melanesian and Australian Aboriginal people. Spectacularly, neither signature of interbreeding is observed in people of African descent. So, we learn that the descendants of modern human populations that migrated out of Africa are mongrels owing to dalliances that occurred while their ancestors were trekking their way around the world. Intriguingly, when the genetic analyses revealed that Neanderthals had red hair, speculation arose as to the origin of red hair in some modern-day Scottish people—it is, after all, an unusual human trait. But the Scots can rest easy knowing that at least this part of their heritage did not come from Neanderthals—the gene causing red hair in modern humans differs from that in Neanderthals.

The era of our occupation of the world might have been a time when sightings of yeti, abominable snowmen, bigfoots, and possibly even hobbits were common, because there would have been at least three and perhaps as many as six distinct human species simultaneously walking the Earth. In addition to ourselves, the Neanderthals, the remnants of
Homo
erectus
and Denisovan populations in Asia, and an unnamed archaic
Homo
species in India, there was possibly one other.
Homo floresiensis
, discovered in 2004 and nicknamed “Hobbits” by newspaper editors straining for a headline, stood around three feet tall. These tiny upright apes lived in caves in an isolated pocket deep in the jungles of the Indonesian island of Flores, possibly until 17,000 years ago. Nobody can be sure but they appear to be a dwarfed and small-brained descendant species of the
H. erectus
populations that had left Africa. Features of their anatomy, at least, indicate they are a separate branch of
Homo
evolution to our own. They almost certainly survived longer than the other competitors to modern humans by staying out of sight—there is no evidence that modern human populations ever made contact with them.

After around 28,000 years ago the only places left on Earth for modern humans to occupy had never before seen human species of any kind. By around 18,000 years ago, groups of what we would now think of as Siberian people moved north and east into a large landmass known as Beringia that had been exposed when sea levels dropped during the last Ice Age. Beringia connected what is now present-day Russia and Alaska, allowing these Siberian people to walk into the Americas. They quickly colonized the northern and southern landmasses of this large continent that spanned nearly the entire north-south axis of the world. People might have reached Cape Horn at the southern tip of South America—nearly 9,000 miles in a straight line from where they first entered North America—by as early as 15,000 years ago, although the evidence is controversial. To get there would have meant moving out of cold polar regions through the temperate climes of North America, across the dry deserts of Mexico, through Central America, and then down the rugged coasts of Patagonia. Eventually people would move all the way to the harsh, cold, wet, and windy environment of the islands of Tierra del Fuego that lie just off the southern tip of South America.