paleoneurology

I've gotten a couple of e-mail questions from readers about this new book, Big Brain: The Origins and Future of Human Intelligence. The authors are Gary Lynch and Richard Granger.

Both Lynch and Granger are experts in neuroscience, with a long list of publications on memory, cortical organization, and chemical regulation of brain activity. Neither of them is an anthropologist or archaeologist.

So I suppose I shouldn't be surprised to see what appears to be complete lunacy in the book description:

Our big brains, our language ability, and our intelligence make us uniquely human. But barely 10,000 years ago--a mere blip in evolutionary time--human-like creatures called "Boskops" flourished in South Africa. They possessed extraordinary features: forebrains roughly 50% larger than ours, and estimated IQs to match--far surpassing our own. Many of these huge fossil skulls have been discovered over the last century, but most of us have never heard of this scientific marvel. Prominent neuroscientists Gary Lynch and Richard Granger compare the contents of the Boskop brain and our own brains today, and arrive at startling conclusions about our intelligence and creativity. Connecting cutting-edge theories of genetics, evolution, language, memory, learning, and intelligence, Lynch and Granger show the implications of large brains on a broad array of fields, from the current state of the art in Alzheimer's and other brain disorders, to new advances in brain-based robots that see and converse with us, and the means by which neural prosthetics-- replacement parts for the brain--are being designed and tested. The authors demystify the complexities of our brains in this fascinating and accessible book, and give us tantalizing insights into our humanity--its past, and its future.

Now, I haven't read the book, and this is not a review. I think a book that puts together the state of the art in neuroscience and tries to relate that to many aspects of human evolution would be a great book. Maybe this book has some of that stuff in it.

But it seems pretty evident from the description that there has been a major misfire. If the description of the book is accurate then they have the evolutionary biology almost entirely wrong. I assume the description is at least in the ballpark, since it is the publisher's description, and it's borne out by this Discover magazine review:

Judging from fossil remains, scientists say the Boskops were similar to modern humans but had small, childlike faces and huge melon heads that held brains about 30 percent larger than our own.

That's what fascinates psychiatrist Gary Lynch and cognitive scientist Richard Granger. "Just as we're smarter than apes, they were probably smarter than us," they speculate. More insightful and self-reflective than modern humans, with fantastic memories and a penchant for dreaming, the Boskops may have had "an internal mental life literally beyond anything we can imagine."

OK, that's a pretty surprising story: an ancient race with unique mental endowments, living in an exotic part of the world. It sounds uncannily like the Atlantis myth. What is the reality here?

First, if you do a simple Google Scholar search for "Boskop", you will discover that this has not been a going topic in human evolution for nearly fifty years. Most intellectual effort on the topic of "Boskopoids" happened between 1915 and 1930. I want to emphasize how easy it is to discover these things by a simple Google search. This is obscure knowledge, but for a good reason -- it's obsolete and has been for fifty years!

The supposed "Boskop race" was named after a South African skull -- consisting of frontal and parietal bones, with a partial occiput, one temporal and a fragment of mandible -- found on a Transvaal farm in 1913. The skull is a large one, with an estimated endocranial volume of 1800 ml. But it is hardly complete, and arguments about its overall size -- exacerbated by its thickness, which confuses estimates based on regression from external measurements -- have ranged from 1700 to 2000 ml. It is large, but well within the range of sizes found in recent males.

Robert Broom named the skull Homo capensis, emphasizing its differences from recent peoples of the region, and proposing a close relationship with European Cro-Magnons. Other remains found later were also attributed to this "type," and so the "Boskop race" became a category of paleoanthropology. Few people know that before Raymond Dart made his name by analyzing and reporting on the Taung skull, he had written in to Nature with a description of "Boskopoid" crania (Dart 1923).

But this concept of a "Boskop race" did not emerge from any clear understanding of the South African past. In fact, MSA, LSA, and recent archaeological-associated remains were lumped indiscriminately into the category. What provoked the racial category was a confusion about the relationships of recent and historical southern African remains. Anthropologists had attempted to apply primary racial categories such as "Negroid," "Bushman," "Hottentot" and "Strandloper," corresponding to extant or recent tribes or other groups. But the distinctions between these categories did not appear to extend far into the prehistoric past. So anthropologists looked for the origins of these racial types within the sample of prehistoric crania -- constructing a "Boskopoid" type for those with later "Bush" or "Strandloper" resemblances.

This category became untenable as further information about the archaeology of South Africa came to light. Ronald Singer (1958) reviewed the "Boskop race" evidence as it existed by the 1950's. He concluded that there was no reason to maintain that any "big-headed, small-faced group" had existed in prehistory, separate from the current biological variability of "Bushman, Hottentot and Negro." But that view is unsupportable -- in fact, what happened is that a small set of large crania were taken from a much larger sample of varied crania, and given the name, "Boskopoid." This selection was initially done almost without any regard for archaeological or cultural associations -- any old, large skull was a "Boskop". Later, when a more systematic inventory of archaeological associations was entered into evidence, it became clear that the "Boskop race" was entirely a figment of anthropologists' imaginations. Instead, the MSA-to-LSA population of South Africa had a varied array of features, within the last 20,000 years trending toward those present in historic southern African peoples. Singer ends his paper thusly:

It is now obvious that what was justifiable speculation (because of paucity of data) in 1923, and was apparent as speculation in 1947, is inexcusable to maintain in 1958.

That is pretty much where matters have stood ever since. "Boskopoid" is used only in this historical sense; it is has not been an active unit of analysis since the 1950's. By 1963, Brothwell could claim that Boskop itself was nothing more than a large skull of Khoisan type, leaving the concept of a "Boskop race" far behind.

Today, skeletal remains from South African LSA are generally believed to be ancestral to historic peoples in the region, including the Khoikhoi and San. The ancient people did not mysteriously disappear: they are still with us! The artistic legacy of the ancient peoples, clearly evidenced in rock art, is impressive but no more so than that of the European Upper Paleolithic or that of indigenous Australians.

And their brains were not all that big. Boskop itself is a large skull, but it is a clear standout in the sample of ancient South African crania; other males range from 1350 to 1600 ml (these are documented by Henneberg and Steyn 1993). That is around the same as Upper Paleolithic Europeans and pre-Neolithic Chinese. LSA South Africans fit in with their contemporaries around the world.

To be sure, there has been a reduction in the average brain size in South Africa during the last 10,000 years, and there have been parallel reductions in Europe and China -- pretty much everywhere we have decent samples of skeletons, it looks like brains have been shrinking. This is something I've done quite a bit of research on, and will continue to do so, because it's interesting. But it is hardly a sign that ancient humans had mysterious mental powers -- it is probably a matter of energetic efficiency (brains are expensive), developmental time (brains take a long time to mature) and diet (brains require high protein and fat consumption, less and less available to Holocene populations).

So, how did this idea of ancient Boskops make it into a book by two neuroscientists in 2008?

If not through science, then possibly from science fiction. The "Boskop race" was immortalized in popular writing by Loren Eiseley, who included an essay on Boskop Man in his collection, The Immense Journey, first published in 1958. As you can see, by this time the entire concept of a "Boskop race" had fallen into scientific disrepute. But Eiseley was undeterred: he conjured the idea that the Boskopoids were advanced in their large brains and small faces -- the apex of a trend toward paedomorphism, the retention of juvenile characteristics. In this state, they resembled what Eiseley suggested would be the "Future Man":

We can, of course, repeat the final, unanswerable question: What did this tremendous brain mean to the Boskop people? We can marvel over their curious and exotic anatomy. We can wonder at the mysterious powers hidden in the human body, so potent that once unleashed they brought this more than modern being into existence on the very threshold of the Ice Age.

We can debate for days whether that magnificent cranial endowment actually represented a superior brain. We can smile pityingly at his miserable shell heaps, point to the mute stones that were his only tools. We can do this, but in doing it we are mocking our own rude forefathers of a similar day and time. We are forgetting the high artistic sensitivity which flowered in the closing Ice Age of Europe and which, oddly, blossomed here as well, lingering on even among the dwarfed Bushmen of the Kalahari.

What we can say is that perhaps the unloosed mechanism ran too fast, that the biological clock had speeded them out of their time and place -- a time which ten thousand years later has still not arrived. This, then, was the logical end of complete foetalization: a desperate struggle to survive among a welter of more prolific and aggressive stocks.

For Eiseley, Boskop served as a kind of memento mori -- the so-called advanced race had succumbed to "more prolific and aggressive stocks." A theme of the essay is that the entire idea of "Future Man" is anti-evolutionary -- there are no ineluctible trends of progress in evolution, because such progressive populations may always be endangered by their own direction of change.

I hate to think that the theme of a 2008 book was pulled straight from a 1958 essay, but I don't know where else they would have gotten the idea. No anthropologists have written much about the so-called "Boskopoids" since 1958. There is no such thing as an "IQ estimate" for a fossil human; that's entirely nonsensical. There's no question that there have been massive cultural changes in the last 10,000 years. But the idea that our brains' functions have atrophied from some Pleistocene state has been left long behind in the dust of nineteenth-century race studies.

So I'm left wondering: Why would two neuroscientists, after going to all the trouble to write a book about the evolution of the human brain, use completely obsolete anthropological information without doing a simple Google search to see if the facts have stayed the same as in 1923?

I don't have an answer, but I'm interested in reading the book to see if it lives up to its billing.

UPDATE (2010-01-04): Discover magazine has printed a long except from the book. The information about the "Boskop race" is more than fifty years out of date. I reflect on the excerpt ("Return of the 'amazing' Boskops").

References:

Broom R. 1918. The evidence afforded by the Boskop skull of a new species of primitive man (Homo capensis). Anthropol Pap Am Mus Nat Hist 23 (2):63-79.

Brothwell DR. 1963. Evidence of early population change in central and southern Africa: Doubts and problems. Man 63:101-104.

Dart R. 1923. Boskop remains from the south-east African coast. Nature 112:623-625.

Henneberg M, Steyn M. 1993. Trends in cranial capacity and cranial index in Subsaharan Africa during the Holocene. Am J Hum Biol 5:473-479.

Singer R. The Boskop "race" problem. Man 58:173-178.