I hate the cover of The Humans Who Went Extinct
(THWWE). There’s an image of the savannah at sunset and superimposed in the right-hand corner is the face of a waifish Neanderthal child. Very adorable. But every time I look at it, I have visions of thuggish Cro-Magnons smashing through a sleepy Neanderthal camp bashing in this kid’s head and tossing her infant siblings up in the air to catch them on their spears.
That aside, THWWE is a fascinating interpretation of the hominid family bush, our place on it, and the places of our cousins. Finlayson doesn’t advocate a radically new perspective but he does want to reassess how much we can know based on the available genetic, fossil and archaeological evidence, and argue that we still have a long road ahead before coming to a definitive narrative (if ever).
Over the last couple of months I’ve read two other works that bear on this topic – The Origin of Consciousness in the Breakdown of the Bicameral Mind – and it’s instructive to see the different interpretations reached by these four authors. Where Jaynes saw human consciousness arising very late – within the last 3,000 years – Finlayson is of that school (of which I’m an auditing student, as well) which argues that “consciousness” to some degree is an outgrowth of a suitably complex brain. He ascribes it to earlier hominids, australopithecines, and primates in general, as well as cetaceans, octopi, elephants – basically all the higher order animals – as well as modern humans. The author argues that modern human success is the result of favorable climate and cultural factors with little contribution from biology – at least no significant contribution in the last 150,000 to 200,000 years. Which places him in clear opposition to both Jaynes and Cochran and Harpending, the latter of whom see genetic mutations as the basis for nearly every development in hominid history. Finlayson’s viewpoint isn’t completely unbalanced: We’re descended from a line of primates better adapted to the climatic conditions that prevailed over a large portion of the Eurasian-African super-continent at a particular point in history that allowed them to spread out over a wide range. But the final advantages that catapulted modern H. sapiens
over Neanderthals and others were climatic and cultural.
A constant theme throughout the book is that modern humans are the product of chance. At any point in the story, a different climate, a more disease-resistant population, or any other variable could have favored a cousin species and would have produced a far different world then the one we live in today.
So what were these initial lucky breaks that has brought us to where we currently stand?
1. In general, primates have flexible joints. It made brachiating (tree climbing) easier and allowed some of them to come down to the ground and walk upright.
2. When the tropical forests that were our primatial cradle began to retreat and fragment due to climate change, our primate ancestors who lived on the margins of the range were able to adapt to a bipedal stance, among other things.
This concept of living on the margins is another important idea in Finlayson’s argument. In essence, when a species finds itself in crisis, it’s the populations on the margins of its range that do best – if they’re able to adapt at all. Time and again, our progenitors were caught at the edges and forced to adapt. As mentioned, Finlayson sees less and less direct evolutionary pressure as time goes on in this change and a greater role for culture. But the defining factor is always climate: Absent the catalyst of environmental change, there’s vanishingly little pressure for either biological or
One more point about margins: They’re regions of ecological diversity and the species living there are adapted to exploiting a wider variety of resources to survive. This flexibility makes them “innovators” as compared to the “conservatives” – those stodgy, stay at homes who populate the heartlands of a range.
3. Among the “other things” mentioned above was an omnivorous diet. Fruits, nuts and the occasional insect may have been on the original menu but hominid digestive tracts can handle a wide variety of cuisines. Critical for our ancestors who found themselves very far from the tropical Kansas of our origins.
The first widespread expansion of the Homo
genus came with H. erectus
- venerable icon of paleoarchaeology textbooks and probably one of our direct ancestors. Finlayson is at pains to point out that we don’t have enough evidence to reconstruct direct connections between hominid fossils. Any claims to the contrary are provisional and can be upset by the next find. (The evidence often consist of nothing more than a few bone fragments and some teeth. The prominence given to Lucy, the australopithecine girl, is due to the completeness of the skeleton, c. 40%, which tends to make it loom larger than it deserves. Though she’s clearly on the road to Homo
, Lucy is not necessarily a direct ancestor to our version.)
But back to Erectus: By about 1 million years ago (1 mya), their populations stretched from China to the Atlantic and extended down the eastern side of Africa (there’s a nice map of this on p. 60 of my edition). Then disaster struck – the cycle of ice ages and interglacials kicked into gear and hominids experienced fragmentation, decimation, recovery, and then further fragmentations, decimations and recoveries (or not) in approx. 100,000-year cycles. One of these relict populations produced H. heidelbergensis
, an offshoot of which further evolved into Neanderthals. Another fragment became the proto-H. sapiens
who were our direct ancestors.
One of Finlayson’s more interesting interpretations of the evidence is that the Neanderthals were the last, moribund population of the Heidelberg line. The cyclical population collapses, the disappearance of the climate zones Neanderthal had evolved in, and the more flexible cultures of H. sapiens
drove them into extinction. But that doesn’t mean that Neanderthals, or Heidelberg humans, were unsuccessful as a species. They survived for half a million years or more and kept modern humans out of Europe until about 45,000 years ago. Their nemesis, according to Finlayson, was Mother Nature. Had Europe retained the forests, climate and fauna in which Heidelberg was born, early humans would have been far less successful in penetrating Europe and prevented from doing so for far longer. This points up a weakness, I think, in Finlayson’s argument: The near absence of any consideration of biological evolution. He seems to be of the view that Neanderthal and Cro-Magnon were essentially the same mentally; purely cultural and climatic factors allowed the latter to prevail. If that’s the essential difference, why weren’t Neanderthal able to adopt Cro-Magnon methods? Perhaps Finlayson avoids the subject because we don’t have sufficient evidence yet to say anything useful about the subject. Genetic assays of the Neanderthal genome is an exciting new branch of science but still in its infancy, despite its impressive achievements to date. Finlayson is perhaps wise in remaining agnostic.
Most reconstructions of prehistoric humans put the Agricultural Revolution (c. 12,000 years ago) as the decisive moment in our evolution that solidified H. sapiens’
place as the dominant hominid. Finlayson argues that the real revolution took place 30,000 years earlier among a population of humans struggling to survive on the steppes between the Black and Caspian seas. Here, some tribe discovered how to store food and cooperate at large scales. In a word, they had discovered “surpluses” and how to manage them. This new way of life was so successful that it had transformed every culture throughout Eurasia within 20,000 years – from the edges of China straight across to the Atlantic and (most significantly) in the Middle East, where there turned out to be a wealth of exploitable plants and animals to support the looming farming age.
The epilog – “Children of Chance” – summarizes Finlayson’s views. In the course of 1.5 to 2 million years a succession of hominids were in the right places at the right time with the right adaptive abilities to exploit and survive climatic changes and displace older, less flexible populations. The author’s outlook for human life, as a species, is optimistic – hominids have a few more chapters to write – but, in the short term, he sees a period of disruption and displacement that will alter how H. sapiens
lives in ways at least as fundamental as the discoveries of surpluses and farming. He believes the survivors of the coming crunch will be those living, as usual, on the margins. As he puts it, “Taming the future is the essence of the human story. Recall that the successful populations that ultimately led to us were always those living on the edge of others who monopolized the good-quality territory. We were born from the poor and feeble that had to spend every ounce of energy searching for the scraps that kept them alive. This may seem a little undignified for those of us who see ourselves at the pinnacle of evolution but that is the sobering reality of our story. Every step of the way in the unpredictable story that led us was marked by populations of innovators living on the periphery” (p. 214).
I have no illusions about where I live – I’m a product of the heartlands, that “good-quality territory” that’s rapidly becoming untenable. I can only hope that the real crunch holds off until I’m safely dead or near enough that it doesn’t matter :-)
More seriously, I highly recommend this book. It’s very well and clearly written, and it packs an amazing amount of information into its 220 pages. As a plus, the endnotes provide some useful guides to further reading.