When Chris Stringer started his graduate research in anthropology in 1970, the prevailing view among his peers was that modern humans had evolved separately from earlier hominids (like Neanderthals) in widely different parts of the world.
This was the multiregionalist view.
Times have changed.
Stringer’s new book, Lone Survivors: How We Came to be the Only Humans on Earth, is a careful review of the latest research on human origins–in particular, how genomics has dramatically changed the field. (I’ve written about him previously here.)
And while Stringer argues that the multiregionalist view has been decisively shown to be wrong, the model that has come to replace it … is by no means uncomplicated. (And in nine chapters and 278 pages, he lays it all out.)
Proponents of an alternative view, that of a Recent African Origin (RAO) for humanity, began to gain ground in the late 1980s, Stringer chief among them–when mitochondrial DNA studies pointed to an African female (dubbed ‘Eve’ after the Biblical account in the Book of Genesis) as the common ancestor of everyone, or put another way: the source of mitochondrial DNA passed down through the ages on the matrilineal side to everyone living today.
This discovery was quite at odds with what the multiregional theory would have predicted (separate mitochondrial lineages for populations in different regions–Asia, South America, Africa).
And that was a problem. The multiregional model gave Africa no special place in human evolution, even though Darwin himself believed Africa to be the continent from which humans originally emerged. Furthermore, as Stringer writes, the theory claimed “specific connections in individual features between Homo erectus fossils more than a million years old in each region and humans in the same regions today.”
As the genetic evidence grew, that claim became harder to defend. But while the multiregional theory lost support, it did not disappear, and now it may enjoy a new lease on life, albeit in form much different from the one championed by its original proponents.
As Stringer writes, new genomic studies –including sequencing of the Neanderthal genome and that of the more recently discovered archaic humans dubbed Denisovan — in combination with fossil evidence from different regions of Africa have persuaded him that a kind of ‘local’, African-based multiregionalism may turn out to be the more accurate account of human evolution.
Overall, I think that the preeminence of Africa in the story of modern human origins was a question of its larger geographic and human population size, which gave greater opportunities for morphological and behavioral variations, and for innovations to develop and be conserved, rather than the result of a special evolutionary pathway. “Modernity” was not a package that had a unique African origin in one time, place, and population, but was a composite whose elements appeared at different times and places and were then gradually assembled to assume the form we recognize today. [p. 267]
He also points out, that the ability of early humans to imitate and conform was probably more important to the success of a regional population than the evolution of intelligence in the abstract.
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