The normal story we are told is that as rose civilization, so declined evolution. The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, inverts that formula as indicated by the title. The idea that humans are beyond evolution isn’t limited just to non-scientists, Steve Jones, an evolutionary geneticist, made the same argument last year. I’ve pointed why the emergence of modern culture and all its accoutrements, such as effective medicine, does not mean that the power of evolutionary forces are somehow negated. In The 10,000 Year Explosion Greg Cochran and Henry Harpending suggest that the rise of complex societies, and in particular agriculture, increased the tempo of evolution! Contrary to the idea that humanity is the post-evolutionary animal, Cochran & Harpending sketch out compelling reasons why one can not separate our biological heritage from our cultural development (and vice versa).
Not only are there theoretical reasons why evolution should not stop, but a slew of recent research suggests that the human genome is characterized by non-trivial levels of natural selection even within the past few thousand years. The 10,000 Year Explosion draws upon this research, as well as Cochran and John Hawks’ model of adaptive acceleration. But while the papers I point to above are basically genetics leavened by a sprinkling of historical events, The 10,000 Year Explosion is to a large extent a work of history which is informed by biological science. The relationship between history and biology should be obvious since the origins of the latter are as natural history, though today it spans the gamut from biophysics to paleontology. Evolutionary change occurs in an environmental context, and cultural change affects the environmental context. Not only that, but the human “environment” is to a large extent self-created, our species’ expansion to northern climes only being enabled by the utilization of clothing derived from other animals.
Cochran & Harpending thematic structure is relatively simple. They begin at a coarse scale of space & time, and slowly converge upon fine-grained instances of evolution in action. By taking a synthetic vantage point on human history The 10,000 Year Explosion clarifies historical issues, and shows just how human creativity has had a feedback relationship with biological evolution. Instead of a duality or opposition between nature and nurture, a story is told which shows how nature and environment and human creativity operative together in an almost symphonic manner, as cultural changes trigger biological changes and those themselves open up new cultural possibilities. The protean nature of human culture naturally results in the inference that rather than a species which evolution forgot, we may actually be on the crest of the evolutionary wave.
Though there is a fair amount of population genetic algebra for those with a technical inclination, the meat of the book are several case studies. Questions such as the Indo-European expansion and the rise to prominence of Ashkenazi Jews are examined through the lens of evolutionary genetics. The conclusions and arguments outlined in these sections are often provocative, but in the “post-genomic era” we are already taking steps toward consilience, so this is only the first of no doubt many intellectual endeavors to navigate the waters between disciplines. Despite the abstruse theoretical frameworks, the concreteness of the specific illustrations as well as the clean and compact prose renders The 10,000 Year Explosion a relatively quickly read, and so an excellent introduction to the discoveries of the new century.
Related: The website of the book.