Steven Pinker’s recent essay attacking group selection has been roundly criticized for its misrepresentation of evolutionary theory, archaic appeals to parsimony, and dismissal of recent work on human altruism. Here I’d like to address a particular undercurrent in the monograph: the intersection between evolutionary theory and causation in human history.
In several places, Pinker contrasts evolution by natural selection with the phrase “ordinary cause and effect”, which instead describes geological processes like the erosion of mountains, or in human affairs the rise of states and spread of new technologies. The rapid adoption of European muskets by Japanese samurai during the 1500s is, to borrow Pinker’s language for an example I’m familiar with, a “banal” and “obvious” story of a superior weapon simply sweeping in. Appealing to general theoretical concepts like “natural selection” here is “pointlessly redescribing ordinary cause-and-effect sequences.”
Yet this dichotomy does violence to what is (perhaps!) the most significant feature of Charles Darwin’s theory of evolution: its complete ordinariness. Discarding previous appeals to special, invisible forces, Darwin realized that all of life’s evolution is but a long-term consequence of quotidian events in the lives of organisms, what we’d otherwise call their “history”.
It’s rare to actually have recorded histories of non-humans animals, but when we do, we tend to make a big deal out of them. The meticulous work of Peter and Rosemary Grant’s team in the Galapagos, documenting the lives and deaths of entire islands of Darwin’s finches, has been celebrated as a textbook case of evolution in action [1]. With really nothing more than careful recording of births and deaths among birds, along with their physical features, we can actually see the population’s average characteristics changing, season by season, drought by drought, just as Darwin imagined.
So why reserve a special term like “natural selection” for events like the 1977 drought on Daphne Major at all? Why not simply say, “finches with bigger beaks could eat tougher seeds, and so do better in hard times?” Pinker’s justification, which is quite good, is that this simple process leads to an amazing and unexpected long-run result: adaptation, and eventually the creation of new species.
The problem, of course, is that counterintuitive outcomes also arise in geology and human history. Pinker’s dismissive erosion example aside, Darwin was first introduced to the implications of relentless, incremental change by geologist Charles Lyell. A copy of Principles of Geology accompanied the 22-year-old on the HMS Beagle, and Darwin’s Journal is filled with geological observations and speculations. By applying Lyell’s ideas,Darwin correctly guessed the complex origins of Pacific atolls (once coral reefs ringing now-eroded volcanic islands).
Likewise, the “obvious” or “banal” diffusion of technologies in human history are often not so obvious. Despite its early popularity in feudal Japan, the Portuguese matchlock was an ineffective weapon of war; expensive, highly inaccurate, prone to explode, useless when wet, and painfully slow to reload, the gun’s full utility was realized only well after widespread adoption and improvement by innovators like Oda Nobunaga [2]. True also of automobiles and personal computers, this counterintuitive regularity in the evolution of technology led historian George Basalla to quip, “Invention is the mother of necessity.” [3]
So trying to contrast the “ordinary” with “natural selection” is at the very least unwise. And in biology, we don’t value such ideas just because they help describe the non-obvious (though that is important!). “By direct study it will never be possible to achieve the same understanding of the marsupial or dinosaur radiation as of the Darwin’s Finch radiation,” notes Peter Grant of his work on Daphne Major, “but the principles established for the finches can be applied to the marsupials and dinosaurs.”[4]
Pinker is apparently hostile to something similar for human history, derisively asking us, “what does “natural selection” add to the historian’s commonplace that some groups have traits that cause them to grow more populous, or wealthier, or more powerful, or to conquer more territory, than others?”
As Pinker’s language gives away, though, historians often struggle to explain events at all. As we’ve seen, “obvious” answers for the diffusion of innovations often fail. For popular topics, like the Fall of Rome, hundreds of distinct explanations have been proposed with no consensus emerging (and some even doubting that Rome fell at all!) [5].
And even those who have defended the profession from anti-causal postmodernism, like Richard J. Evans and John Lewis Gaddis, agree that cause-and-effect explanations for a particular event usually apply only to that place, at that time [6,7]. From experience, historians as a whole tend to be extremely skeptical of generalized theories of historical change.
Yet within the last several decades, mathematically-minded historians [8], economists [9,10], psychologists [11], anthropologists [12-14] and sociologists [15] have used the tools of Darwinian evolution and dynamical systems theory to produce substantive gains to our understanding of ourselves as a species.
Because humans are so uniquely dependent on culture and technology, this Darwinian approach necessarily develops new evolutionary ideas (e.g. blending inheritance, strategic learning biases, and gene-culture feedback loops). And, because of the overriding importance of groups to human existence, models of cultural group selection have also become a staple of this analysis.
As in evolutionary ecology, the value of these models (including group selection ones) is often not in their ability to make predictions, but to help us understand essential causal relationships. They “sharpen intuition and sensitize imagination” for how particular social phenomena arise, and prompt us to look in places we otherwise wouldn’t have [16]. These models also tell us that seemingly trivial examples (yes, including the spread of steel-belted radials and touchtone phones) can provide deep insight into similar phenomena throughout human history.
1. See Jonathan Weiner’s The Beak of the Finch for an excellent overview of the Grants’ work in the Galapagos.
2. Noel Perrin, Giving Up the Gun: Japan’s Reversion to the Sword, 1543-1879. (Boston: D.R. Godine, 1979).
3. George Basalla, The Evolution of Technology. (Cambridge University Press, 1988), p.6.
4. Peter R. Grant. Ecology and Evolution of Darwin’s Finches. (Princeton University Press, 1986), p.404.
5. Peter Turchin. “Arise ‘cliodynamics’”. Nature. (2004) 454, pp.34-35.
6. John Lewis Gaddis, The Landscape of History: How Historians Map the Past (Oxyford University Press, 2002).
7. Richard J. Evans. In Defense of History. (WW Norton, 1997).
8. Peter Turchin. Historical Dynamics: Why States Rise and Fall. (Princeton University Press, 2003).
9. Samuel Bowles. Microeconomics. (PrincetonUniversity Press, 2004).
10. Herbert Gintis. Game Theory Evolving. 2nd ed. (Princeton University Press, 2009).
11. Maciej Chudek, Joseph Henrich. “Culture–gene coevolution, norm-psychology and the emergence of human prosociality”, Trends in Cognitive Science. 15(5) 2011, pp.218-226.
12. Richard McElreath, Robert Boyd, Peter J. Richerson, “Shared norms and the evolution of ethnic markers” Current Anthropology. (2003) 44(1), pp.122-129.
13. Peter J. Richerson, Robert Boyd, Not By Genes Alone (University ofChicago Press, 2005).
14. Alex Mesoudi, Andew Whiten, Kevin Laland. “Towards a unified science of cultural evolution”, Behavioral and Brain Sciences. (2006) 29, pp.329-383.
15. Rodney Stark, Rise of Christianity: A Sociologist Reconsiders History. (Princeton, N.J.: Princeton University Press, 1996).
16. Quote from Jonathan Roughgarden, Theory of Population Genetics and Evolutionary Ecology: An Introduction (New York: Macmillan, 1979); thanks to Ryan Baldini for the reference.
Peter Turchin
July 2, 2012
Bret, thanks for bringing up Rodney Stark’s work, which is a great example of using (implicitly) a group selectionist reasoning about why early Christianity was so successful. For example, he discusses how early Christians ministered to people, even non-believers, who were suffering from the plague. There are clearly costs! In fact, pagan doctors would run away from diseased patients, because they did not want to contract the plague. Christians helped, and many died, but in the end Christianity won over the Roman religion.
More generally, much of research by sociologists and political scientists on history is implicitly (and sometimes explicitly) group selectionist. I expect two new commentaries on this issue, taking opposing sides, to appear at the SEF in the next few days.
Have you read Farewell to the Alms by Gregory Clark? Another example of a very Darwinian approach to history, but one taking resolutely the selfish gene point of view.
Matt Zimmerman
July 4, 2012
Bret, your opening reminds me of Huxley’s supposed response to Darwin’s theory natural selection: “How extremely stupid of me not to have thought of that!”
The point being that the logic of natural selection seems exceedingly obvious once it is pointed out.
Jones sabo he explained
April 12, 2013
Magnificent website. Lots of useful info here. I’m sending it to some buddies ans additionally sharing in delicious. And of course, thank you to your effort!