According to Pinker, group selection “adds nothing to conventional history” as an explanation of cultural change. Rather than arising from processes of random mutation and indifferent selection, he argues, cultural traits arise and spread as a result of the complex intentions and interactions of agents: “Conquerors, leaders, elites, visionaries, social entrepreneurs, and other innovators use their highly nonrandom brains to figure out tactics and institutions and norms and beliefs that are intelligently designed in response to a felt need”. Pinker insists that natural selection isn’t natural selection unless mutations are random: “unless the traits arose from multiple iterations of copying of random errors in a finite pool of replicators, the theory of natural selection adds nothing to ordinary cause and effect”. In short, the variability that natural selection acts upon must be randomly generated rather than deliberately generated – and, in that sense, intelligently designed.
As Pinker himself observes, however, nobody ‘owns’ the theory of natural selection. On our view, the process by which variable forms are intelligently generated and intelligently selected is not a theoretically banal alternative to natural selection, but rather a special variety of natural selection, in which the generation and selection of variability is accomplished via cognitive systems (themselves evolved). As we see it, the theoretical utility of the concept does not derive from the randomness of the variability (or from the indifference of the selective process), but rather from the efficiency of explanation it affords. In any case, deliberate alterations in artifact form are arguably just as “random” as genetic mutations – both are subject to a host of constraints within which new variants can occur.
While we agree with Pinker that the multifarious intentions of agents shape the emergence and spread of cultural traits, these are merely aspects of the proximate causation in cultural evolution and do not preclude the possibility of selection by consequences. Moreover, a comprehensive account of cultural evolution should really consider all of Tinbergen’s Four Whys. Consider the problem of explaining why the moving pistons in a car drive the main axle. A proximate explanation is that the pistons in an internal combustion engine deliver power to the car’s wheels via a series of mechanical devices such as a crankshaft and gearbox. (And of course these features were ‘designed’ that way.) An ultimate explanation is that vehicles equipped with this arrangement actually move and the design was selected for. But a more complete explanation must also consider developmental questions concerning the nature and sequencing of the car assembly process, such as how pistons, crankshafts, gearboxes, and axles come to be installed and connected up. And we also need to consider the constraints on design imposed by prior forms of motor vehicle construction, which are essentially questions about phylogeny.
If the ‘ultimate’ perspective adds explanatory power in the biological domain (it is more efficient to talk about how singing is a behaviour that was selected for in male songbirds because it served to attract females in the ancestral past, than to give a blow-by-blow account of the fates of every songbird in evolutionary history) then it should also add explanatory power in the cultural domain (if the design of a product involved thousands of iterations of generate-and-test then it is more efficient to talk about how a particular design feature is adapted to, say, a particular commercial environment, than to detail the fates of the myriad intermediate forms along the way). Perhaps the reason why Pinker finds it hard to recognize this is that intelligent design is commonly associated with supernatural theories of creation that have no place in science. If so, that impediment to understanding can surely be dismissed. To appreciate that designed creations evolve does not expose us to the charge of theistic creationism.
Harvey and Ryan: Basically, I am in agreement with you. One of fundamental postulates of Darwinian evolution is that there is heritable variation; this variation does not need to be generated by a purely random process, as Pinker claims.
But I also think that Pinker goes way too far when he portrays the process that generates cultural variation as purely non-random – “intelligently designed.” People are just not that smart – if we were, we would have long ago solved all the societal problems.
In reality, when one examines how the process of, for example, techological change is actually accomplished, to a first approximation it is done by something that very closely resembles blind tinkering (a thousand of chimps banging on a thousand typewriters comes to mind) followed by a selection process.
This tinkering can happen quite rapidly within people’s brains. Take an example that most of practicing scientists are intimately familiar with – coming up with an explanation for an empirically observed pattern. I have introspected on this issue, and I believe that what happens is that your brain rapidly throws out numerous possibilities most of which you immediatey reject, and voila! you have an explanation (or two). Because the process is very rapid (it may even appear instantaneous) it is sometimes not even apparent to you, but at the base it can be reasonably described as random generation of explanations followed by very rapid selection – weeding out of less ‘fit’ variants.
So from the multilevel selection point of view even ‘intelligent design’ may well be approximated by rapid selection of randomly generated variants that happens within human brains. At the next level, such ‘intelligently designed’ ideas have to compete by attempting to spread to other individuals, and there may also be competition between groups that converge to different equilibria.
This is one of the greatest insights of Darwin – that what looks like intelligent design may actually be a selection process over randomly generated variants.
The main idea Harvey Whitehouse and Ryan McKay articulate is correct and it has a long pedigree.
Darwin in the Descent of Man articulates a two-stage hypothesis for the evolution of morality. In “primordial times” natural selection acted at the tribal scale to favor the evolution of the “social instincts” such as sympathy and patriotism. In “civilized times” the social instincts acted to guide the evolution of traditions, customs, laws, and religion via the “example of the best men,” “public opinion,” and “a good education.” In civilized times natural selection “plays a subordinate role.”
I read this but didn’t completely understand what Darwin was driving at until I read Robert Richards’ important book on Darwin and the Emergence of Evolutionary Theories of Mind and Behavior in the late 1980s.
Don Campbell in 1965 reinvented the same idea, more or less, and called it “vicarious selection.” Evolved systems for learning and decision-making acted as stand-ins for natural selection and in the case of culture acted as forces shaping culture.
Cavalli-Sforza and Feldman termed the same process “cultural selection” in their ’81 book.
To Rob Boyd and I “cultural selection” is too easily confused with actual natural selection on cultural variation. Anyway, we wanted a more fine-grained taxonomy. In our 1985 book we used the term “decision-making forces” for the general phenomenon and subdivided these into “guided variation,” the non-random creation of new cultural variants by learning and invention, and “biases,” non-random choices among existing cultural variants. Biases we divided in turn into several types.
Our students and some other folk have followed our scheme, with important suggestions about terminology from Joe Henrich and Richard McElreath. Rob and I have written several versions of an historical essay about all this, the latest one cited below.
Both of these are available on the authors’ web pages.
Henrich J & McElreath R (2003) The evolution of cultural evolution. Evolutionary Anthropology 12:123-135.
Richerson PJ & Boyd R (2010) The Darwinian theory of cultural evolution and gene-culture coevolution. Evolution Since Darwin: The First 150 years, eds Bell MA, Futuyma DJ, Eanes WF, & Levinton JS (Sinauer, Sunderland MA).
A beautiful response.
I’m also glad that Harvey and Ryan have addressed this part of Steve’s essay. Here are some quick points.
1) This part of Steve’s essay is a critique of cultural evolution, not group selection. His claim about intentional psychological processes not qualifying as cultural evolution would apply even if cultural evolution took place entirely at the individual level.
2) The question of whether Lamarkian evolution still qualifies as evolution has been discussed by Jablonka and Lamb in “Evolution in Four Dimensions” and by Hodgson and Knudsen in “Darwin’s Conjecture”. The conclusion is that if Lamark was correct, Darwin’s theory of natural selection would be much the same. And, as any historian of evolution knows, Darwin was Lamarkian in his own views on heredity.
3) In Darwin’s Cathedral, I divide proximate causes of cultural change into three categories; a) Conscious intentional processes such as overt decision making.
b) Psychological processes that take place between conscious awareness, such as some forms of imitation.
c) A raw process of variation and selection; many inadvertent social experiments, only a few of which hang together.
All of these are demonstrably important in historical change. Steve needs to acknowledge the role of (c), even if he thinks that (a) and (b) don’t qualify as cultural evolution.
4) There is ample evidence that intentional planning might as well be random when unforeseen consequences and the complex interactions between different people’s intentional plans are taken into account. In the classic case of the Nuer replacing the Dinka, members of both tribes were assiduously attending to their own affairs in local terms (tending their cattle, raising their crops, conducing their raids) without a glimmer of awareness of the consequences operating over decades and generations.
5) In many ways, Steve’s essays represents the whole field of evolutionary psychology associated with Cosmides/Tooby/Pinker, which had little to say about transmitted culture and tried to explain everything it could in terms of so-called invoked culture. This is also true for what Steve says about group selection. His school of EP has always taken the 1960’s consensus as gospel without questioning it or adding to it. That’s why Steve’s essay is a sign of progress–like Rip Van Winkle waking up after a long nap.
Re: (2). I am puzzled, however, why Hodgson and Knudsen insist that cultural evolution is not Lamarckian. See, e.g., here: http://www.geoffrey-hodgson.info/lamarckism.htm
Hodgson has a chapter in “Darwin’s Conjecture” on the topic of Lamarckism. Lamarckian inheritance depends on the germ line products being reverse engineered and coded into the germ line. That’s not impossible in cultural evolution – but it isn’t common either.
Most alledged “inheritance of acquired characteristics” in cultural evolution is similar to the way in which dogs pass on the fleas they acquired during their life to their own offspring. That phenomenon not considered to be a case of Lamarckian inheritance by most biologists.
Tim, why is reverse-engineering rare in cultural transmission? Richerson and Boyd argue that cultural transmission by imitation is precisely that, and that’s one of the major modes of cultural variant spread.
Much depends on how the split between the germ line its products is made – and that’s a controversial issue:
“Internalists” place the cultural “germ line” in the brain, and categorise behaviour as being forms of expression of that heritable material. However, internalism has many problems: it struggles to say what qualifies as being a “brain” (now that there is much cultural transmission between computers) and it destroys germ line continuity, replacing it with a “bizarre” flip-flopping between the germ line and its products.
By contrast there is “externalism”, which has many prominent supporters. This puts the germ, line in brains, artifacts and behaviour equally. In externalism, behaviour and artifacts contain heritable cultural information. The movement between brains and behaviour is not obviously more deserving of the label of being a “developmental program” than the shift from behaviour to brains. Instead, both are seen as a form of biological metamorphosis. Cultural mutations in behaviour are passed on, just as cultural mutations in brains are. Heritable behavioural mutations often take place in the components of it that could be described as being in the “germ line” – rather than being “germ line products” – and that perspective results in no Lamarckian inheritance.
Copying CDs, DVDs, solid-state memory, speech and writing seems to have a pretty neglible Lamarckian component. Most cultural inheritance these days looks a lot like the “ordinary” Darwinian kind – that involves pretty low-level template copying.
Externalism doesn’t rule out the possibility of Lamarckian inheritance. Sometimes, there’s a pretty unambiguous split that shows where there is a developmental program – and it is pretty clear that it is being reverse-engineered. However, most cases of imitation aren’t really like that. In those cases, describing imitation as a case of “Lamarckian inheritance” seems like “reaching”.
Tim, on your point about dogs passing fleas: but how is that different from passing on plant cultivars and domesticated animals?!
In the context of Lamarckian inheritance, dog fleas seem very similar to inherited plant cultivars and inherited domesticated animals. Hodgson says this about dog fleas, on
the page you previously cited:
“Almost all biologists now deny that acquired characters can be inherited in the biological sphere and reject Lamarckism, but none of them would see the phenomena described in the previous paragraph as a challenge to the current consensus in biology.”
Pinker articulates his position on video – in my “Memetics features directed mutations” article.
“if the design of a product involved thousands of iterations of generate-and-test then it is more efficient to talk about how a particular design feature is adapted to, say, a particular commercial environment, than to detail the fates of the myriad intermediate forms along the way”
It would surely be appropriate to mention genetic algorithms (and evolutionary computation more broadly) in this context. New software and hardware designs are created by means which are explicitly Darwinian in their inspiration. And this is not a speculative thing done only in the most ivory of towers, but a workaday tool of industry—even in the John Deere factories!
http://www.talkorigins.org/faqs/genalg/genalg.html
https://en.wikipedia.org/wiki/List_of_genetic_algorithm_applications
Pinker already mentions genetic algorithms in his essay and believes it is fine to treat think of them in terms of natural selection.