1960: a Moroccan miner is picking away at a cave wall, looking for the mineral baryte, when he hits a white rock. Closer inspection reveals it’s a skull. He removes it with care and presents it to his engineer, who keeps it for a while as a souvenir. But one day, when visiting the town of Rabat, the engineer decides to hand it over to experts at the university. They’re intrigued, and set about examining it, but their archaeological dating techniques are primitive, especially when it came to ancient bones, and their knowledge about human origins is also lacking. Their best guess is that the skull may be 40,000 years old and possibly Neanderthal, which seems odd, because Neanderthals never set foot in Morocco.
Skip forward forty-four years, to 2004. The Jebel Irhoud Moroccan cave remains of interest to those excited by old bones. More skulls and tools have been discovered over the years, which is why the French paleoanthropologist Jean-Jacques Hublin is there with a team of scientists. Among an abundance of fossils, one find particularly excites them: five skulls from people who appeared to have died at about the same time.
Alongside the skulls, in the same layer of rock, they uncover more human bones and teeth, and scores of carefully crafted flint blades, including spear blades designed to be mounted on wooden shafts. Some of these blades show signs of being burned, perhaps thrown into cooking fires after use, or maybe used as the points of barbecue forks. This offers the scientists the means to date them, and they also cross-check with a technique of calculating age by assessing the fossilisation of dental tissue. These test results provide a shock: the tools and skulls are around 315,000 years old, which puts back the date of the first known appearance of modern humans (Homo sapiens) by about 120,000 years.
The skulls look pretty much like present-day humans from the front; they suggest wide faces with heavy brows and smallish chins. ‘The face is that of somebody you could come across in the Metro,’1 said Hublin, who is now director of the department of human evolution at Leipzig’s prestigious Max Planck Institute for Evolutionary Anthropology. Skull measurement also suggests their brains were the same size as those of contemporary humans, but with one key difference: they had longer, lower braincases, more typical of earlier hominins than the more rounded braincases of all modern humans; seen from the side, they would appear slightly odd.
It might be that the different skull shape suggests different cognitive capacities among these very early humans but we can’t be sure. Certainly, aspects of their behaviour appear to be as sophisticated as those of later humans. These gazelle-cooking cave dwellers seemed capable of making a variety of tools and weapons, including wooden-handled spears, and their flint came from another site nearly forty kilometres away, which suggests the ability to plan and to travel long distances to seek resources.
Over the next thirteen years Professor Hublin’s team continued to work on the site, making further finds and analysing the bones and tools, using new techniques of genetic analysis, until they were ready to go public. In 2017, the team published a paper in the journal Nature that shocked the archaeological world and overturned conventional wisdom on human origins; not only of the dating of modern human origins but also of the distribution. The other huge implication of this discovery is, as the paper’s authors put it, that ‘these data suggest a larger scale, potentially pan-African origin.’2 This quote relates to an alternative to the conventional wisdom that all humans had a single common African ancestor, and raises the possibility that, instead, we had many common ancestors from different parts of Africa.
Adding to this pan-Africanist picture are recent discoveries at an archaeological site called Olorgesailie, in a dry basin of what was once a lake in the Eastern Rift Valley of Kenya. The first interesting artefacts were discovered in 1919 but real excavation started only in 1943, directed by the pioneering British-Kenyan archaeologists Mary and Louis Leakey, with Italian prisoners of war providing the hard physical graft. The site became famous for its hoard of hand axes made between about 600,000 and 1.2 million years ago, along with fossils of a variety of extinct animals, including giant baboons and some bones and part of a skull of a Homo erectus child, dated at nearly one million years old.
The paleoanthropologist Rick Potts, who leads the Smithsonian’s Human Origins Program, began working in Olorgesailie in 1985, for what he thought was a three-year stint that has ended up passing the thirty-three-year mark. In recent years his team has made a series of remarkable discoveries, including carefully crafted human tools made from a volcanic black rock, obsidian. Potts’s team was able to date these tools by analysing radioactive isotopes of uranium and argon contained in the obsidian; they dated to between 305,000 and 320,000 years old. In other words, they are about the same age as the human skulls and tools found in Morocco. And yet these tools were typical of the Middle Stone Age period, previously thought to have started well over a hundred thousand years later.
The hoard included spear tips, blades, scraping tools and awls (small pointed piercing tools). But the most intriguing discovery related to the stuff they were made from. The closest source of obsidian is 100 km away as the crow flies, provided the crow flies over rugged mountains. And yet, huge amounts were imported. Potts and his team considered all the possible explanations and concluded the only answer was long-distance trade, which would mean this trading network preceded any other known network by more than 100,000 years. Further evidence of trade came from other discoveries, including lumps of manganese ore and iron oxide that had been ground into powder with awls, almost certainly to create paint, which suggests symbolic activity.
Potts has no doubt about the significance of these finds. ‘What we’re seeing in Olorgesailie is right at the root of Homo sapiens,’ he said in a 2018 interview. ‘It seems that this package of cognitive and social behaviours was there from the outset.’3 The American archaeologist Alison Brooks, who together with her colleague Sally McBrearty has done so much to draw the world’s attention to the wealth of prehistoric evidence of modern human behaviour in Africa, studied the artefacts at the Kenyan site: ‘There was an argument that Homo sapiens came along and then developed all these things but now it seems that the behaviour and the morphology came along together,’ she said.4 What Brooks and Potts are suggesting is that the cognitive capacity for modern human behaviour was there right from the start; from the time the first anatomically modern humans evolved.
It’s time to reverse gear and consider the deep origins of the hominin family. Humans, chimpanzees and bonobos had a common ancestor more than six million years ago, but it was another four million years before the first hominins – Homo habilis and Homo gautengensis – evolved 2.5 million years ago, after which several sub-species popped up in Africa, soon to migrate to Asia and Europe. In looking at our ancestral cousins, the starting point is usually said to be Homo erectus, so named because they walked upright, but there is a view that several other early hominins, previously identified as other species, may really have been early examples of Homo erectus. Five Homo erectus skulls and skeletons, discovered along with their stone tools in Georgia in 2005, were of individuals thought to have been killed by sabre-toothed tigers between 1.77 and 1.85 million years ago. An interesting detail is that there were significant differences among the group; had they been found separately, they might well have been identified as different species. This led palaeontologists to question whether African skulls previously discovered were really examples of different hominin branches rather than part of the variety in Homo erectus. However, the British anthropologist Chris Stringer has his doubts:
Africa is a huge continent with a deep record of the earliest stages of human evolution and there certainly seems to have been species-level diversity there prior to two million years ago. So I still doubt that all of the ‘early Homo’ fossils can reasonably be lumped into an evolving Homo erectus lineage. We need similarly complete African fossils from two to 2.5 million years ago to test that idea properly.5
Anyway, Homo erectus arrived on the scene more than two million years ago and soon migrated over the Levantine corridor and the Horn of Africa, spreading to Asia (China, India, Indonesia and Java) and through parts of Europe, living in hunter-gatherer communities, using fire, travelling by raft, making tools and weapons and caring for the old and the ill. Over time, they developed brains at least three-quarters the size of modern humans’.
The next big hitter in our past is Homo heidelbergensis (thought to have evolved from Homo ergaster, an African offshoot from Homo erectus), which shows further skull expansion, suggesting a larger brain relative to body size. These hominins first emerged about 700,000 years ago and were still around less than 200,000 years ago. In this time, they spread to Europe (their name comes from the discovery of one of their skeletons in a cave in Germany) and through much of East and Southern Africa. They hunted with stone-pointed wooden spears, used cutting tools, and may have been the first in the human family to bury their dead. They may have painted with red ochre pigment, and also had the genetic and auditory equipment to be at least anatomically capable of speaking and hearing words, suggesting linguistic capacity. Homo heidelbergensis was the direct evolutionary ancestor of the Neanderthals and of the Denisovans, and probably of us.
As we’ve seen, the origins of modern humans have been moved back, but even before 315,000 years ago, archaic Homo sapiens were involved in symbolic behaviour, including painting, using tools and creating weapons. Archaeologists in Zambia, for example, have found pigments and paint-grinding equipment at least 350,000 years old.
There is much debate about where and why the evolutionary change to greater intellect happened. On the why question, some have emphasised physiological factors such as evolving to walk upright or evolving to have opposable thumbs, while others have looked to the environment. A recent environmental theory is that sudden shifts in the climate of the East African Rift Valley created a need to adapt to dramatic environmental change. ‘It seems modern humans were born from climate change,’ said Mark Maslin, professor of geography at University College London, who co-authored a geographical study on climate change in this period.6 His fellow author, Dr Susanne Shultz, from the University of Manchester, added that 1.9 million years ago a number of new species appeared, which they believe was directly related to new ecological conditions in the Rift Valley, in particular the appearance of deep freshwater lakes. ‘Among these species was early Homo erectus with a brain 80 per cent bigger than its predecessors,’ she said.7 Another compelling theory is that the social skills demanded for living alongside other hominins in communities provided the impetus, with the brightest and most innovative in the group more likely to flourish and to produce more offspring. But this is entirely speculative; it might be that the strongest and most attractive had more children than the smartest.
All these reasons relate to natural selection but it’s possible that the growth of the modern human brain was at least partly the result of a coincidence of genetic acquisitions through genetic drift (a random process, often occurring in population bottlenecks). Whatever the causes, the human brain evolved rapidly over a short space of evolutionary time. Two and a half million years ago hominin brains were not much larger than those of chimpanzees. By 315,000 years ago the brain had trebled in size and it’s possible it came with the full range of intellectual and creative potential we have today.
The Kenyan tools and trade networks, the Moroccan skulls and a 195,000-year-old Ethiopian skull, among others, all provide evidence that modern humans were evolving in multiple sites around Africa. Another example is the Florisbad Skull, found in the Free State province of South Africa in 1932 along with tools from the Middle Stone Age period. One of the interesting things about this skull was that it had a brain volume of 1,400 cm3, larger than that of modern humans (this does not in itself suggest greater brain capacity; it might be that its bearer had a bigger body). However, because it had some archaic features, and was first classified as belonging to a near ancestor, it was dubbed Homo helmei. In the 1990s it was dated, using the technique of electron spin resonance, and found to be 260,000 years old. Following the Moroccan discovery, it has been reclassified as ‘archaic Homo sapiens’ or just plain ‘Homo sapiens’.
Until recently the debate around the geographical origins of humans seemed to have been settled. The idea so decisively seen off was one suggested by the American anthropologist Milford Wolpoff; that modern humans evolved more or less simultaneously in different parts of the world.8 If he was right, we’d anticipate big genetic differences, possibly relating to intelligence, although Wolpoff refuted this, referring to the gene flow resulting from interbreeding between people. ‘Humans today are widely variable but without enough population differences to be considered subspecies or races,’ he said.9
However, all recent genetic evidence favours the idea that humans have their evolutionary roots in Africa. The fossil record shows modern humans going back more than 300,000 years in Africa, but the record of skulls and bones from Australia, China, India and Europe is far more recent, in most cases after Homo erectus is thought to have died out. The genetic record also shows that modern humans are closely related to each other and to what the British paleoanthropologist Stringer called ‘all the fossil people’, in reference to the ancient skulls from Europe, Africa, China and Australia that he has studied. ‘If modern humans had evolved all over the world,’ he wrote, ‘you would expect them to have deep roots back to their ancestors in that place but [the skulls] weren’t showing that. They were showing a compact group, as though they had originated from the same place.’10
This conclusion was bolstered in 1987 by DNA evidence said to suggest that a common, female ancestor of all humans alive today (popularly known as ‘mitochondrial Eve’) lived around 200,000 years ago, probably in East Africa. The dating is imprecise because it is based on an assessment of the expected rate of human genetic mutation, which is uncertain. The current best guess is 160,000 years. Either way, it was impossible to reconcile with the Wolpoff theory, which would suggest our last common ancestor lived around two million years ago.
The term ‘mitochondrial Eve’ is a bit misleading, because it conjures images of a single, intrepid, pioneering, human female ancestor. However, she would have lived in a community, and there were certainly Homo sapiens communities in other parts of Africa whose lineages did not survive. Some have questioned the assumption that mitochondrial DNA evidence alone confirms the ‘out of Africa’ thesis. For example, the geneticist Alan Templeton noted that mitochondrial DNA patterns could not be equated with actual human populations and suggested the data could also be used to support multi-regionalist theory.11
The idea that Africa was the human cradle has been reinforced by evidence that, compared to other mammals, there is little genetic diversity between different human populations (if we’d evolved wherever Homo erectus travelled, we’d expect far more diversity) and, even more decisively, by evidence that genetic diversity is significantly higher among African populations than anywhere else in the world. This is what you’d expect if small groups of Africans migrated relatively recently, because the gene pool of the billions of descendants of these migrants would be drawn from these small groups rather than from Africa as a whole, or from whole regions of Africa.
There are two key caveats to the out-of-Africa idea. The first is decisive: genetic evidence that humans interbred with Neanderthals, and with another hominin, the Denisovans, after migrating from Africa. Non-African people have small traces of Neanderthal and/or Denisovan DNA in quantities that vary depending on the regional origins of their ancestors. The second is more speculative but gaining ground: the increasing evidence, particularly from the fossil record, that modern humans evolved all over Africa. This would not in itself discredit the original out-of-Africa theory of a single small population responsible for populating the world. However, if modern humans were making appearances all over Africa it seems unlikely that only one ancestral line survived.
Several experts have shifted their thinking recently. The University of Oxford archaeologist Eleanor Scerri drew together leading anthropologists, archaeologists, geneticists and climatologists to review the evidence, and the result was a World Health Organization-funded paper that has shaken their world. These twenty-three authors ‘challenge the view that our species, Homo sapiens, evolved within a single population and/or region of Africa’ and instead argue that humans ‘evolved within a set of interlinked groups living across Africa, whose connectivity changed through time’.12 They believe that the whole of Africa, not just one small corner, is the cradle of modern humanity.
One of their arguments relates to the oldest African population, the San of Southern Africa (also called ‘Bushmen’). The authors note that the San have the highest levels of genetic diversity among all human populations today, which suggests an early divergence from common African ancestors somewhere between 150,000 and 300,000 years ago. This divergence lasted until the arrival from East Africa of Bantu-speaking people less than 2,000 years ago; the San shared genes with them, and later with Europeans and mixed-race people. A similar perspective is offered by the Harvard geneticist David Reich, who was part of a team that studied the genetics of the San and other populations in 2016. He suggests that the separation began around 200,000 years ago and was mostly complete by 100,000 years ago, with evidence of only limited gene sharing with other African populations after that. Reich says it is possible that ‘Pygmy’ groups from Central African forests have a similarly distinctive ancestry.13 It is worth remembering that the earlier dates of divergence pre-date the current best guess for ‘mitochondrial Eve’, of 160,000 years ago.
The twenty-three WHO-backed scientists put forward several other paleontological, genetic and environmental arguments for the African multi-regionalist view, one being that early Homo sapiens fossils ‘do not demonstrate a similar linear progression towards contemporary human morphology’. In other words, they don’t all look alike; instead, they exhibit ‘remarkable morphological diversity and geographical spread’.14 They show that these early humans were spread all over Africa, rather than being concentrated in one place, and that their skulls looked different from place to place, even though they started using similar, more sophisticated, tools at similar times. The authors paint a picture of ‘semi-isolated’ populations adapting to local ecologies but ultimately connecting with each other, prompting a ‘sporadic gene flow’. Incidentally, the time period they’re talking about starts at least half a million years ago, but not until about 100,000 years ago did all or most humans have the same rounded skull shape we have today. In the preceding 400,000 years there was a more diverse range of human size and shape, including skull shape and size. Most of these groups evolved in isolation for long spells, each developing distinct features; more distinct than the differences between modern humans. But as the environment changed and impenetrable areas became more penetrable, people moved, had sex, and exchanged both genes and ideas. And eventually a more cohesive humanity emerged.
The twenty-three authors also raise the possibility that ‘African archaic interbreeding’15 might help explain the slightly different skull shapes found in different parts of Africa. Recent genetic analysis shows that it is more than a possibility. About half a million years ago, Homo sapiens began to separate from Homo heidelbergensis but the two groups continued to coexist for hundreds of thousands of years. There is now compelling genetic evidence that humans bred with an archaic ghost population probably around 35,000 years ago,16 although this date is far from certain. The result is that around 2 per cent of the genetic ancestry of some contemporary African populations derives from this source, about the same amount as the Neanderthal genetic contribution to non-Africans,17 and with close matches to the Neanderthal DNA sequences in non-Africans, which is hardly surprising when you consider that Neanderthals also descended from Homo heidelbergensis. This interbreeding may have continued, at least in isolated pockets: 11,000-year-old human remains found in West Africa show archaic, pre-Homo sapiens features.18
Modern humans in Africa also coexisted with at least one other hominin: the recently discovered, small-statured and small-brained hominin Homo naledi, several of whose remains were found in 2015 in a cave in the Gauteng province of South Africa, along with their tools. In 2017 these skeletons were dated at between 236,000 and 335,000 years old. So far, there is no evidence that H. sapiens interbred with them.
It is now certain from full genome genetic analysis that humans interbred with Neanderthals soon after leaving Africa, probably in the Middle East around 49,000–54,000 years ago, and this contributed to non-African DNA (2 per cent on average). Pockets of interbreeding continued after humans arrived in Europe 43,000 years ago; the evidence for this is drawn from a skeleton in a Romanian cave showing 6 to 9 per cent Neanderthal ancestry, suggesting a Neanderthal ancestor about six generations before.19 However, these later pairings do not appear to have contributed to modern human DNA, possibly because lower fertility among human-Neanderthal hybrids meant most lineages died out. One contribution the Neanderthals made to modern European and East Asian DNA relates to keratin proteins, naturally selected because they provide protection in cold environments.20
Around 45,000 years ago humans bred with another recently discovered offshoot from Homo heidelbergensis, the Denisovans, of which one branch lived in parts of Europe and another in New Guinea and the Philippines. Between 2 and 6 per cent of the DNA of people with deep historical roots in some of these areas comes from the Denisovans (the higher end found among people in New Guinea). We know far less about the Denisovans than we do the Neanderthals because the archaeological record is sparse; a few teeth, some finger bones, a toe bone and a bracelet. However, we do know from whole genome DNA analysis that like humans and Neanderthals, they branched off from Homo heidelbergensis about 400,000 years ago and were still around 40,000 years ago. We also know that while they had much in common with Neanderthals and interbred with them, they were genetically distinct. From their teeth we believe they had a vegetable-rich diet and from the bracelet we assume they were capable of symbolic thinking. One of their contributions to modern humanity is a gene mutation, carried by modern Tibetans, that helps people living at high altitude.21
Modern humans also coexisted with Homo floresiensis (popularly known as the ‘hobbit’ because the first skeleton found was only 1.1m tall) who lived on the island of Flores in Indonesia between 190,000 and 50,000 years ago. They went extinct about the same time as modern humans arrived in the area, suggesting that we may have been responsible for their demise. Recent genetic analysis has shown that Homo floresiensis was not a diminutive version of Homo erectus, but rather a distinct species of hominin. It is now thought that their ancestors were among the first to leave Africa, perhaps two million years ago, and that they evolved further in Asia. Despite their small bodies and brains, they had sophisticated stone tools, probably used fire for cooking and hunted cooperatively. The latest discovery of hominins who coexisted with humans came from the 67,000-year-old remains of several individuals found in an island cave in the Philippines. Homo luzonensis were small, tool-using tree-climbers who seem to have reached their home by raft. It is also likely that modern humans coexisted with Homo erectus (who became extinct about 140–150,000 years ago), when H erectus was living exclusively in Asia and modern humans were beginning to venture out of Africa.
So for about 90 per cent of human existence, we have coexisted with at least seven other species of hominin and interbred with at least three. Given the rate of recent discoveries, it seems likely that we will find other unknown species.
The fishermen who lived in a cliff-top cave on the Indian Ocean side of South Africa liked to paint. They used large shells to collect colourful dirt, pounded it, ground it and enriched it with iron oxide to create an ochre-coloured powder, which they carefully blended with mammal bone marrow and finally with charcoal. Next, they liquefied the mixture, and stirred it, before using spatulas and home-made crayons to decorate their tools, their artwork, their beads and probably themselves. In this sense, they behaved pretty much like cave artists in Europe or Australia or elsewhere in Africa. Except for one detail: the blended ochre work of South Africa’s fishermen has been dated as at least 55,000 years older than any other cave-art workshop previously discovered.
What is clear from the excavation of the Blombos Cave – about 320 kilometres east of Cape Town – is that this small community of hunter-fisher people living about 100,000 years ago knew a great deal about seeking out and storing substances, and in combining them they must have had a basic knowledge of chemistry. They used their paint not just for utilitarian ends but with decorative purpose. They engaged in creative, self-aware behaviour that would have involved discussing ideas, planning and abstract thinking. The earliest discovery of residues of ochre used by cave people goes back at least 160,000 years and as we’ve seen, people in Kenya were extracting red paint from iron-bearing rocks more than 300,000 years ago, but the Blombos discovery, which involves blended ochre paint, is even more significant, because it reveals symbolic activity, which would necessarily involve the use of complex language, creative thought, planning and conception. As the lead researcher, Christopher Henshilwood, put it: ‘We’re pushing back the date of symbolic thinking in modern humans – far, far back.’22
Among the many astonishing discoveries from Blombos made by archaeologists over the past two decades are two large ochre plaques inscribed with geometric designs of interlocking triangles and horizontal lines, dated at 77,000 years old; twice the age of anything similar found in Europe.23 We don’t know what these engravings meant but finds at other coastal caves in the area have revealed similar symbols, suggesting they were widely used at the time, perhaps to keep records. The American paleoanthropologist Ian Tattersall, who has long studied European cave art, said this constituted ‘the most remarkable early evidence of symbolic activity’.24 Later, archaeologists discovered a broken-off fragment of rock that had been drawn on with an ochre crayon in a criss-cross pattern that looks as if it’s part of a larger design. In 2018, after seven years of tests, this was dated as 73,000 years old, making it the world’s oldest rock drawing. ‘There’s no doubt that it’s a symbol that meant something to the people who made it,’ Henshilwood was quoted as saying. ‘It’s a symbol that’s been repeated over and over again.’25
Other discoveries include 77,000-year-old spearheads shaped using a technique called ‘pressure flaking’, previously thought to have first emerged in Europe 20,000 years ago, and engravings on bone dated at about 70,000 years.26 Blombos has also produced beads from necklaces and other ornaments, showing that members of this community adorned themselves, which provides further indication of the nature of their self-conscious intelligence.27 Archaeologists working there have, in addition, uncovered a range of other tools, weapons and implements, including bone-point hooks used to catch large catfish, thought to be more than 70,000 years old. This suggests that these people had a lifestyle similar to that of the cave dwellers of Europe tens of thousands of years later.
Although Africa is under-researched, Blombos is hardly an isolated case. Other examples come from a cave at Pinnacle Point on the south coast of South Africa, where in 2009 a team of researchers found stone tools that had been heated to more than 300°, using a technique of burying them under a fire, which made them easier to shape. Tools showing clear evidence of this form of heat treatment were found to be 72,000 years old but others, which were more ambiguous, went back 164,000 years. Until these discoveries, the consensus among archaeologists was that this form of heat treatment emerged in Europe around 20,000 years ago. The team also found scraped and ground ochre used for painting, barbed bone points for shell fishing and small sharpened blades for arrows and spears, dated at 71,000 years old; at least 11,000 years older than previous examples.28
Examples of symbolic behaviour from ancient times in Africa are emerging at a rapid clip as archaeologists, palaeontologists and geneticists combine. There’s evidence of decorative objects and body ornaments such as pendants, bangles and beads that pre-date those of Europe by tens of thousands of years. Pierced shells for necklaces, dated at 70,000 years, were found in the Porc-Epic Cave in Ethiopia, a similar age to those in the South African caves, while beads and other ornaments have been found in Morocco that might be 130,000 years old. At least 100,000 years ago people began burying their dead, and more than 60,000 years back grave gifts began to appear, reflecting belief in an afterlife. Evidence of the symbolic organisation of space, dating back 100,000 years, was found at the Klasies River mouth in South Africa, along with evidence of controlled burning, an early agricultural technique to stimulate corn production, and grindstones to process the corn, while in Nazlet Sabaha in Egypt, people were mining chert, to make tools, 100,000 years ago.
All over Africa the archaeological record shows economic activity and technological innovation going back well over 100,000 years. Sophisticated bone tools, dated at 80,000 years, of a form previously thought to have been introduced in Europe, were found at a site in Katanda in the Congo. Small tools that are components for larger tools have been found at several sites dating back 65,000 years. This technique only became commonly used in Europe around 20,000 years ago. Recent discoveries in Kenya suggest long-distance trade goes back more than 300,000 years. There’s also evidence from around 100,000 years ago of hunting techniques such as pitfall traps, clothes made from animal hide, and buttons and needles made from bone.29
One reason why these are such recent discoveries – most of them made since the new millennium – is that until recently there was not much happening in terms of archaeological digs in large parts of Africa. (The same applies to genetic analysis, which is strongly Eurocentric.) This is one reason why much of the evidence comes from South Africa; more archaeologists work there. As the biological anthropologists Sally McBrearty and Alison Brooks put it: ‘Africa is vast, researchers are few and research history is short.’30 They also suggest that a factor in our skewed perception of the African record is the reliance on research conducted in caves (such as Blombos), which provide ideal conditions for preservation but are hardly typical, because ‘the vast majority of African occupation sites are in open-air contexts.’31 What is clear, however, is that evidence of innovative, creative, self-aware, symbolic behaviour goes back a very long way: at least 100,000 years and, from the recent Kenyan and Moroccan evidence, perhaps more than 300,000 years.
This brings me to the subject of the Israeli historian Yuval Noah Harari, whose bestselling book Sapiens: A Brief History of Humankind, published in 2014, declared that 70,000 years ago humans began a ‘cognitive revolution’. He starts with the daily use of fire for cooking around 300,000 years ago. This led to the evolution of a shorter intestinal track, meaning more energy to spare, and larger brains, heralding the arrival of Homo sapiens 200,000 years ago.32 But although these early H. sapiens had big brains, their brain structure was ‘probably different from ours’. Harari adds: ‘They looked like us but their cognitive abilities – learning, remembering, communicating – were far more limited. Teaching such an ancient sapiens English, persuading him of the truth of Christian dogma or getting him to understand the theory of evolution would probably have been hopeless undertakings.’33 But this all changed ‘as a matter of pure chance’34 because ‘accidental mutations changed the inner wiring of the brains of sapiens enabling them to think in unprecedented ways and to communicate using an altogether new type of language.’ He adds: ‘We might call it the Tree of Knowledge mutation.’35 After this, Homo sapiens just like us started ‘doing very special things’.36
A similar view was advanced by Harari’s intellectual hero, the geographer Jared Diamond. In his bestseller, Guns, Germs and Steel, he proposed that humans experienced a ‘Great Leap Forward’ 50,000 years ago.37 This was prompted by the ‘perfection of the voice box and hence the anatomical basis of modern language’ and also ‘a change in brain organisation’.38 Before then, he tells us, humans had modern bodies but not modern brains, which would suggest that the Homo sapiens who made their way to Australia 70,000 years ago were less than fully human in the modern sense and even those who started their trek through Eurasia 60,000 years ago would have missed the ‘Leap Forward’ boat.
This pair were preceded by the anthropologist Richard Klein, who proposed that modern human behaviour was prompted by a single mutation of a brain gene about 50,000 years ago. Humans were incapable of modern behaviour before then.39 Klein could produce no convincing evidence of this gene mutation, because there was none. But he was writing before the work of McBrearty and Brooks was published, as was Diamond, and before the evidence from the Blombos and Pinnacle Point caves emerged, so perhaps they can be partially excused. Not so Harari. It is clear he was writing in complete ignorance of any of the African discoveries that had been prominently published in several books and academic papers more than a decade before Sapiens.
Harari chooses fire as the catalyst for bigger brains, saying its daily use started only 300,000 years ago, and that Homo sapiens only started 200,000 years ago. Today, most scientists working in this field put the starting time for the evolution of Homo sapiens at 500,000 years ago, and recent discoveries have shown ‘modern’ human behaviour going back more than 300,000 years. There is clear evidence that Homo erectus used fire for cooking (in other words, ‘daily use’) 600,000 years ago, and perhaps as long as two million years ago. Homo heidelbergensis also used fire for cooking, and the Moroccan Homo sapiens cave-dwellers were cooking with fire 315,000 years ago. Even the small-brained Homo floresiensis cooked using fire. As the prime candidate for getting the brain ready for Harari’s ‘pure chance’ cognitive revolution, fire is a dud. But really, there’s no evidence for any genetic kick-start or ‘great leap forward’.
The Harvard geneticist David Reich shows in his book on ancient DNA that not only does the archaeological case fail but so does the genetic. One candidate proposed as the spark for the cognitive revolution is the FOXP2 gene, which is important for language and speech. But this evolved 1.9 million years ago.40 Reich adds that if there were a single mutation essential to modern human behaviour, you’d expect it to be more common in some populations than others. But this has not happened. As Reich puts it: ‘This seems hard to reconcile with the fact that all people today are capable of mastering conceptual language and innovating their culture in a way that is a hallmark of modern humans.’41
A major premise of two bestselling books on human origins is, quite simply, wrong. But Harari and Diamond are far from the worst offenders. The view that the Eurasian experience prompted an intelligence spurt has an even more dubious past. One example comes from the American anthropologists Henry Harpending and Gregory Cochran, who speculate that genetic changes prompted the explosion in European, Middle Eastern and Asian cultures after their arrival in Eurasia, although they add that ‘[o]bviously, something important, some genetic change, occurred in Africa that allowed moderns to expand out of Africa and supplant archaic species.’42
This would not explain why previous hominin populations did the same. Migration is usually explained in terms of the need for more hunting and gathering space when populations are rising, not in terms of superior intelligence. As I will discuss later in this book, Harpending and Cochran are at the forefront of race science. They achieved notoriety for their contribution to a paper arguing that Ashkenazi Jews are innately more intelligent than anyone else, and Harpending has also argued sub-Saharan Africans have not evolved for hard work.43
A related view, held by almost all those who pursue a race science agenda, is that cold climates prompted the evolutionary advance in intelligence for those who migrated. The argument, advanced most avidly by the overtly racist psychologists such as Richard Lynn and J. Philippe Rushton, is that the cold posed challenges that required long-term planning, nudging selection for intelligence-related genes. Aside from the fact that their argument is contradicted by their own IQ data – for example, one lower-IQ group in Lynn’s IQ-of-Nations schema is the Inuits (Eskimos) – there’s the question of why cold rather than heat would prompt evolution for advanced cognition. Did the Neanderthals or Siberian Denisovans who lived through ice ages in Europe for 400,000 years evolve to have more intelligence than us? And when it comes to the idea that higher intelligence got us moving, what of Homo heidelbergensis, Homo erectus and Homo floresiensis? Some of them left Africa nearly two million years before modern humans did (the remains and tools of a hominin – probably early Homo erectus – were recently found in China and dated at more than two million years old44).
Most biological anthropologists who speculate about the environmental and social factors that might have nudged evolution for higher intelligence tend to focus more on the impact of communal living: when our hominin ancestors started living in small communities they would have needed social skills of various kinds to prosper, to attract mates and to pass on their genes, which would have applied as much in warm climates as cold. In other words, when it comes to the role natural selection plays for intelligence in people, where to look is at other people, and our hominin ancestors started living in communities millions of years before arriving in Eurasia.
The challenges of a warm climate – such as having to survive drought, floods and longer-term climate change – seem no less intelligence-demanding than the need to survive cold winters. In any event, the idea of Africa being one happy, warm, easy, undemanding kindergarten is ridiculous. Before the migration to Eurasia, people like us were living in caves by the sea, beside rivers and lakes, in the grassland savannahs, forests, semi-desert areas, snowy mountain regions, tropical forests and many more environments, and they’d been migrating up and down Africa for hundreds of thousands of years.
It is also worth remembering that Africans have more genetic variation than people in the rest of the world, because small groups migrated, so if there were to be natural selection for genes implicated in higher intelligence, this would most likely have happened in Africa. One view, supported by archaeologists such as Henshilwood, is that there was indeed a leap forward (a ‘leap’ spanning tens of thousands of years) and that it happened not in Europe but in Africa, starting at least 160,000 years ago.45
The strongest argument against the Eurasian view comes from evidence that I’ve already touched on. McBrearty and Brooks, who examined this African record of innovation, adaptation and inventiveness, argue that the ‘human evolution’ view of a great leap forward in Europe prompted by some genetic advance suggests a ‘profound Eurocentric bias and a failure to appreciate the depth and breadth of the African archaeological record’.46 They believe the rapidly increasing volume of evidence from archaeological research shows that our pre-human ancestors were well on their way to becoming fully human, in terms of cognitive potential and behaviour, 300,000 years ago.47
Ian Tattersall, a specialist in European cave dwellers, agrees, rejecting the idea of human evolution as ‘a gradual progression from primitiveness to perfection’, arguing that ‘this conceptual hold-over from the past is clearly in error. We are not the result of constant fine-tuning over the aeons.’ He suggests that the earliest anatomically modern humans were born with the full intellectual potential of later humans but this lay fallow until unleashed by cultural stimuli. He also believes there has since been no significant evolutionary advance in the human brain.48 These scientists and archaeologists all agree that by the time Homo sapiens emerged with their current morphology, they had also attained their full intellectual potential.
Much of the focus on the Eurocentric view has come from the flowering of artistic expression in Europe after the Cro-Magnon arrivals. Until recently, the oldest known example of rock art was that in the El Castillo cave in Spain, where one motif was found to be at least 40,000 years old, dating from soon after Homo sapiens arrived in that part of Europe. However, in 2018 that was overtaken by the announcement of the discovery of the 73,000-year-old ochre line drawing on the rock fragment at Blombos. Also in 2018, a painting of a banteng (South Asian wild cow) was discovered on a cave wall in Borneo. Dated as at least 40,000 years old, this is the oldest known example of figurative rock art. Other examples of rock art from the Chauvet Cave in France have been dated at 35,000 years, and rock art really takes off from then.
But Europeans were not alone in painting their caves at this time. Rock paintings of animals at the Apollo 11 Cave complex in Namibia may be more than 27,000 years old. It seems likely that as more African archaeological sites are excavated, even older African examples will emerge, complementing the 2018 Blombos discovery. As it stands, the discoveries over the past two decades at Blombos suggest that artistic expression in Africa predates the earliest European cave art by at least 35,000 years.
However, there’s an obvious flaw in using artistic expression to discern intelligence. At any moment in history some societies have forged ahead in terms of technological and cultural sophistication, while others retain more ancient lifestyles. Writing was ‘invented’ in the heat of Mesopotamia (today’s Iraq) more than 5,000 years ago, when the people of Britain were still hunter-gatherers. In parts of the Amazon and Africa today there are still hunter-gatherers who ignore or avoid modernity; people continue to live traditional lifestyles and reject modernity for all sorts of reasons, which tells us nothing about their innate cognitive capacity.
Two books on contemporary hunter-gatherer communities brought this home to me. In Don’t Sleep, There are Snakes: Life and Language in the Amazonian Jungle,49 the American linguist Daniel Everett describes more than two decades spent living among the Piraha people in a remote part of the Amazon. The chief academic interest in the book comes from what it reveals about language. The Piraha language seems to defy Noam Chomsky and Steven Pinker’s view of innate, universal grammatical systems involving multi-clause sentences; the syntax of the Piraha tonal language appears to be very different.
The Piraha culture also throws into question the common view, held both by religious people and genetic determinists, that religion and belief in an afterlife are ‘hardwired’ human universals. The Piraha have a rich fantasy life and believe in spirits but have no ancestor beliefs, no belief in an afterlife, no creation myths and no sense of a god. They, and their language, show little interest in anything other than the present tense: their attitudes to sex, love, death and parenting are unique. They also have no chiefs, no numbers, no art, no writing and little interest in other cultures and yet they are a vibrant community, routinely described by visitors as extraordinarily happy and content. According to Everett, suicide is unknown, as is any sign of depression. Perhaps it is not so surprising that other than using shotguns for hunting and motorboats for some transport, they show no desire to adopt the more Westernised lifestyles of surrounding tribes. But they are not lacking in cognitive potential. Although Piraha adults showed no inclination to learn to count or read, their young children seemed as perfectly capable of learning these skills as children elsewhere. Archaeologists of the future who mistakenly believed that lack of ‘achievement’ was a sign of cognitive limitation might conclude they had stumbled on a ‘backward’ tribe but when they checked their results with genetic specialists they would discover that the Piraha are the close cousins of a neighbouring tribe known for their ambition, business acumen, love of wealth and learning.
The other book was Intimate Fathers: The Nature and Context of Aka Pygmy Paternal Infant Care50 by the American anthropologist Barry Hewlett. As with the Piraha, this predominantly hunter-gatherer pygmy tribe showed no inclination towards artistic expression or technological innovation. And yet in all sorts of other ways they were innovative, not least in how they brought up their children. Hewlett’s study exposes the solipsism of the view that current Western cultural norms and values are natural and universal. He found that Aka fathers spent five times as much time with their infants as the Western average, and held, or remained within arm’s length of, their babies almost half of the time. They often hugged their infants close to their bodies for an hour or more, offering them their nipples to suck, comforting, cleaning and singing to them at night. Like the Piraha, they did not hit their children or shout at them. The parents readily interchanged roles, with the women playing a significant role in small game net hunting (as did the Piraha women) even when pregnant. Hewlett explains: ‘[T]here’s a level of flexibility that’s virtually unknown in our society. Aka fathers will slip into roles usually occupied by mothers without a second thought and without, more importantly, any loss of status – there’s no stigma involved in the different jobs.’51
I cite these examples of contemporary hunter-gatherers not to glorify their rustic lifestyles. Existential threats, as well as high child and adult mortality rates, suggest otherwise. In both cases the tribespeople show the same range of human nature as the rest of us – deceit, jealousy, drunkenness and violence are certainly in their range, as are love, gentleness, humour and kindness. I use them for two other reasons. First, to make the point that when looking at the prehistoric world ‘achievements’ such as technological innovation and artistic expression might give us strong hints of cognitive potential but their absence does not in itself imply the opposite. Second, it’s all too easy to make the error of assuming that our own way of doing things (such as in gender relations, sexual relations or parental relations) is the norm and therefore natural when really, it is culturally contingent. The Piraha show that even the structure and form of language is, in the long run, environmentally and culturally contingent.
When the fisherfolk of Blombos and Pinnacle Point were mixing their paints, carving their geometric plaques, threading their beads and using extreme heat to shape their blades and tools, other humans might still be behaving like Homo heidelbergensis. They all had the same big, complex brains, with similar innate potential, but their embrace of symbolic behaviour and of new technologies was uneven. It is likely that this potential spread through the increasingly varied and complex use of language and through travel and trade which, in itself, prompted changes in forms of communication including language, rather than through any biological advance. In other words, the human creative potential contained in those large brains emerged more quickly in some areas than in others. Or perhaps just differently.
When did people with intelligence like ours first emerge? When we combine the expanding archaeological record with our rapidly increasing knowledge of genetics it would seem likely that modern human intelligence goes very far back, perhaps all the way back to the arrival of the first anatomically modern humans. We have been fully human in every sense, including cognitive potential and all our immense creative and destructive glory, for far longer than generally assumed.