The 10,000 Year Explosion: How Civilization Accelerated Human Evolution

By Razib Khan | January 26, 2009 8:53 am

5152fXI3EtL._SL500_AA240_.jpgThe 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.

CATEGORIZED UNDER: Evolution
  • D. C. Sessions

    Hardly surprising. Even in the world’s most advanced societies in the late 19th century, infant and child mortality exceeded 50%. Mortality up through reproductive ages was also quite high, asa glance at my (North American) family tree shows, with less than half of the adults making it past 35. There’s lots of room for selection pressure in that kind of environment.
    The interesting question, to me, is whether the same can be said today where pre-reproductive mortality is in single-digit percentages. It would appear that the primary selection pressure today is on fertility, and reading ScienceBlogs would suggest that (per Kornbluth) what we’re selecting against is any inclination to pursue postgraduate education.

  • Tod

    The Middle Eastern region which had “intensive, year-round agriculture” , “division of labour”, and writing long before anyone else ought to have gone much further down the road of selection.
    Cold European countries where these things (and the selective force they exerted) arrived thousands of years later ought to have been held back by comparison. Middle Easterners must have been made significantly more intellectualy capable than Scandinavians at some point.
    The Middle East may have suffered an implosion since then as qualities once selected for became maladaptive. inclination to pursue postgraduate education. could be an contemporary example of this.

  • dearieme

    Are there serious believers in the no-evolution-for-60000-years doctrine who believe it for scientific reasons, or should I assume that it’s always, or almost always, believed for political reasons? In other words, is it merely a sort of wishful thinking, or can a decent case be made for it?

  • http://congenialtimes.blogspot.com Mark

    “The Middle East may have suffered an implosion since then as qualities once selected for became maladaptive. inclination to pursue postgraduate education. could be an contemporary example of this.”
    Arab Muslim populations also experienced significant gene flow during the Islamic slave trade from outside populations. Perhaps this introduced additional alleles into the population that enhanced reproductive success but weren’t as suited to the maintenance of an advanced civilization?

  • Resti

    @Tod

    The Middle Eastern region which had “intensive, year-round agriculture” , “division of labour”, and writing long before anyone else ought to have gone much further down the road of selection.

    Cold European countries where these things (and the selective force they exerted) arrived thousands of years later ought to have been held back by comparison. Middle Easterners must have been made significantly more intellectualy capable than Scandinavians at some point.

    Human beings have legs. At the time when agriculture was developed in the Middle East it is perfectly possible that the majority of the ancestors of present day Scandinavians were physically located in the Middle East where it was happening.
    The spread of agriculture to Europe was possibly just as demic as was the spread of European culture to North America. A native Swede today may have as many genes from the Swedes of the time of the rise of the Fertile Crescent as a typical Ohioan has genes from the Native Americans.

  • Resti

    @Mark

    Arab Muslim populations also experienced significant gene flow during the Islamic slave trade from outside populations. Perhaps this introduced additional alleles into the population that enhanced reproductive success but weren’t as suited to the maintenance of an advanced civilization?

    In what ways do present Arab countries not have an advanced civilization? Relative to western Europe they don’t have a high GDP per capita, but many are still ahead of the poorest “white” countries (e.g. Moldova or Macedonia) even on that score. The technological level of present day Egypt would make the ancient Egyptians gasp in amazement if they could see it. You seem to be making a relative rather than absolute comparison.
    I see little reason to put Arab countries relative lack of development at the door of genes. It was not so long ago that most of southern Europe was at a comparable level, and while agriculture being long enough ago for evolution to be a factor, Europe becoming richer than the Middle East is much, much more recent than that.

  • http://scienceblogs.com/gnxp razib

    The spread of agriculture to Europe was possibly just as demic as was the spread of European culture to North America. A native Swede today may have as many genes from the Swedes of the time of the rise of the Fertile Crescent as a typical Ohioan has genes from the Native Americans.
    you’re off by around 2 orders of magnitude. a native swede probably has on the order of 10-50% (with more studies on the lower range than the high) total genome content attributable to the neolithic demic diffusion from the middle east. the mid-east signal of the ‘wave of advance’ gets weaker with distance….

  • Resti

    you’re off by around 2 orders of magnitude. a native sweden probably has on the order of 10-50% (with more studies on the lower range than the high) total genome content attributable to the neolithic demic diffusion from the middle est.

    Based on what in particular? As far as I was aware this question has not been settled. What is being used as a proxy for pre-neolithic Scandinavian DNA in your estimate, or do we have some? Time measures of genetic changes are hardly useful because they say nothing about the geographic location of the people when these events occurred, and therefore how they relate to the archaeological record re. agriculture. Such studies on modern populations can tell us who is descended from whom, but not the geographical locations of the ancestral populations, and therefore how they fit with the history of agriculture as left by the archaeological record.
    Many studies I’ve seen use the Basques as a proxy for pre-neolithic Europeans. This is in my opinion highly dubious, though they are pre-Indo European expansion linguistically I see little historical reason to believe that the Basques are pre-neolithic in origin any more than any other Europeans. I have never seen a satisfactory explanation for this assumption. Coon had the Basques firmly in the neolithic Middle Eastern origin camp by old style skull measurement in comparison to historical skeletal remains which unlike the genes in modern populations CAN be placed in a particular location at a particular time along with tools and utensils. If the Basques are predominantly post neolithic, many of these studies fall like a pack of cards.
    Assuming linguistic conformity with genes, the fact that the Basques are pre Indo-European can only place them at around the second millenium BC. Anything that speculates on their origins before that time based on language is pure hypothesis. There is a massive time gap between the second millenium BC and the beginnings of agriculture, even at it’s latest anywhere in Europe, and I have never seen it filled by anything but pure convenient assumption by those who hold the Basques up as a remnant of pre agricultural Europe.

  • http://scienceblogs.com/gnxp razib

    Based on what in particular?
    follow these cites. some of your criticisms are well taken. i’ll try to keep it short: some lineages have really deep coalescences in the past. the geographical relationships might have shifted, but daughter populations exhibit a pretty obvious bottleneck effect that allows one to ascertain time depth. *most* northern european lineages separated from modern middle eastern ones well before the demic diffusion of the neolithic period. a minority are related to modern middle eastern ones.
    p.s. there is now ancient DNA extraction. the results are mixed (the focus on mtDNA causes problems).

  • http://congenialtimes.blogspot.com Mark

    Resti said:
    “In what ways do present Arab countries not have an advanced civilization? Relative to western Europe they don’t have a high GDP per capita, but many are still ahead of the poorest “white” countries (e.g. Moldova or Macedonia) even on that score. The technological level of present day Egypt would make the ancient Egyptians gasp in amazement if they could see it. You seem to be making a relative rather than absolute comparison.”
    Well, yes, I was making a relative comparison. The question was why Middle Easterners, who have experienced agriculture the longest, have fallen behind Europeans in recent centuries. Tod suggested it may be because advanced civilization selects against the very alleles necessary for its maintenance. I said that gene flow from other populations may have sped such a process up in the Arab world.
    Resti also said:
    “I see little reason to put Arab countries relative lack of development at the door of genes. It was not so long ago that most of southern Europe was at a comparable level, and while agriculture being long enough ago for evolution to be a factor, Europe becoming richer than the Middle East is much, much more recent than that.”
    And I see no reason to exclude genes as a possible reason for the relative lack of development of the Arab world. I’m not saying that I believe genes ARE the reason or are LIKELY to be a reason. Just that the possibility shouldn’t be dismissed out of hand.

  • Oli

    There is plenty of development in oil producing countries UAE and Saudi. I don’t think that genes have anything to do with this argument. Countries experience varying levels of growth all the time.

  • Roy Wilson

    Interesting theory, but unlikely. Evolution is, first and foremost, influenced by reproduction. Most studies suggest that, instead of the smartest, most capable people reproducing most rapidly, artificial selective pressures are favoring the least intelligent and capable.
    Evolutionary pressures are indeed in play, but not in a positive way.

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This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

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