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March 17th, 2009
Spark Blog: Rewriting the History of the Modern Human Mind

by Graham Chedd

Alison Brooks lets Alan see how perfectly a million-year-old axe fits in his hand. Photo by Larry Engel

We’re in Cambridge, Massachusetts, visiting Harvard and MIT – just across the Charles River from where I’ve lived for almost my whole career as a producer of science programs for public television. So it’s familiar ground. I remember a film shoot on the top of one of the MIT towers (the Green Building, I think) for one of my first NOVA productions, when the scientist held up a ball for a shot that included the golden dome of the State House in Boston as a visual analogy of how far earth is from the sun. That must have been in 1976 or so. The Boston skyline is now very different, with the dome almost lost in a sea of tall modern buildings. That shoot is also memorable because there was a brief glimpse of the top of my head in the rushes, taken while I was with the scientist and the cameraman was lining up his shot from above and behind us. It was the first time I became aware of another emerging shining dome.

One of the people we filmed here is actually a visitor, taking a sabbatical at Harvard’s Peabody Museum from George Washington University, where she is Professor of Archeology and International Affairs. Alison Brooks and a colleague (Sally McBrearty of UConn) set the field of human origins all atwitter almost ten years ago when they published a massive paper in the Journal of Human Evolution challenging the then-prevailing view that the modern human mind suddenly gelled when our ancestors arrived in Europe some 35,000 years ago and began painting the walls of caves in southern France. In other words, that it was in the flickering oil lamps of the artists of Lascaux that the Human Spark ignited.

Sally and Alison had both worked extensively in Africa in the previous decades, and pulling together their own archeological evidence and that of others argued in their JHE paper that instead of a sudden cognitive revolution in Europe, the modern human mind emerged bit by bit much earlier in Africa – that the Human Spark in fact didn’t ignite in one glorious (and European) burst but instead sputtered into existence in the minds of our African ancestors over perhaps a hundred thousand years or even longer.

So entrenched was the idea of a sudden European origin of modern human behavior that the McBrearty-Brooks paper was met with much skepticism when it was published in 2000. But it has since not only convinced most of their colleagues, but was also one of the inspirations for this project. So it was a great opportunity for us to have Alan and Alison get together at the Peabody, in what Alan was enchanted to discover is the museum’s “Stone Age Laboratory.” Alison had spent several hours prowling through the museum’s huge collection of archeological artifacts and had laid out for us a wonderful collection of items made by humans from over 1.7 million years ago in Africa to some 20,000 years ago in Europe.

Alan was very taken by how nicely the million-plus year old stone axes nestled in his hand, but was most struck by the fact that having invented stone hand axes some 1.7 million years ago, we humans stuck with them for most of our existence. Alison showed Alan several much more elaborate tools in stone and bone found in Europe and dating to between 20,000 and 35,000 years ago as the sort of evidence that it was there and then that the Human Spark ignited. “People looked at these and they said, well, there’s a human revolution here. There’s an incredible development, an incredible flowering of human creativity and human inventiveness. It’s a revolution. Something must explain it.”

Alison told Alan that it was a trip as a graduate student to the Kalahari with her then-new husband, John Yellen, that began to plant the seeds of doubt about the conventional wisdom. In the course of his work with the Bushmen, Yellen had discovered an archeological site where there were hundreds of tiny stone points. Alison showed Alan an example: “If you found these in North America, you would say this is an Indian arrowhead, but these were not in North America and, as we were able to show, they were about 75 to 80 thousand years old.”

The Human Spark camera captures Alison and Alan’s exchange as they examine the ancient points. Photo by Maggie Villiger

Alison argues that these points must in fact have been arrowheads.

Alison: “You could put it on a little tiny spear and go after a little tiny antelope, but would you really want to go up against a giant buffalo with something that size?’

Alan: “Not before it was extinct!”

Alison: “Don’t think so. Let’s say those people didn’t have too many descendants, which is what matters after all in evolution.”

Conventional wisdom had the bow and arrow invented perhaps 20,000 years ago – guess where.

So this was the beginning of Alison Brooks’ career-long quest to demonstrate that there was in fact no single cognitive “explosion” that led to the modern human mind; that instead it was built piece by piece in Africa. And this is the theme of what will be the first program in our Human Spark series. Later we will be going with Alison to an archeological site in Kenya she has been excavating for several years now, and which she believes encompasses the critical time – and perhaps the critical place – where the Human Spark first began glimmering into life.

It will be a long way from my academic backyard. But Alison promises some exciting finds…

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