Wednesday, August 08, 2007

The Evolution of Affluence

Cultural evolution can be a controversial topic. When one thinks about evolution it is natural to think about variation and change in the rather straightforward anatomical traits that one can visually assess or the more complex and discrete traits found at the level of the genome. But behaviors, beliefs, attitudes, and the like are no less phenotypes than one's hair or eye color, and they are, for the most part, heritable (there are some curious exceptions, such as celibacy). For some reason the academic interest in the evolution of behaviors, beliefs, attitudes, sometimes classified under the rubric of "cultural evolution", has tended to center in the field of philosophy of biology: one finds few working biologists who specialize in it, and only a handful of sociologists and anthropologists, historians, and economists. This is unfortunate, because it is an empirical discipline in the end, and it needs some folks besides philosophers doing some work if it is to really take off.

The field took a hit in the early days that has not helped it much since. When Edward Osborne Wilson published his Sociobiology: A New Synthesis in 1975 it caused something of a stir among both philosophers, biologists, and sociologists, some of whom saw his interpretation of the interaction between biological traits and human behavior as a thinly-veiled neo-fascism on the rise. That was, of course, a silly idea, but the damage was done, and sociobiology was often viewed with some suspicion during the late 1970s and the 1980s.

Now Gregory Clark, an economic historian at the University of California, Davis, has a new book forthcoming from Princeton University Press (A Farewell to Alms, due out next month) that seems situated to cause a similar stir, though thankfully without the charges of neo-fascism. According to Clark, the growth in affluence that was witnessed by countries where the Industrial Revolution had its greatest impact was a consequence of cultural evolution. That is, whereas historians and economists ordinarily trace the effects of such things as the Industrial Revolution to the institutions and practices that underlie them, Clark wants to trace the whole kit and caboodle to fundamental changes in human behavior that he thinks were consequences of cultural evolution.

In particular, he notes that technological change often increases the capacity of humans to feed and take care of themselves, but often the technological advantage is soon swamped by a "Malthusian trap" in which the population expands in such a way that the overall affluence of the people is not increased in any tangible way. What happened on the eve of the Industrial Revolution was quite interesting. From 1200 to 1800 in England the population went through several evolutionary bottlenecks, such as the Black Death, where the population was suddenly and severely reduced. Casualties were mostly in the cities, and so immigration from the countryside was required to replenish the inhabitants of the large, industrial centers. These people, in turn, came to be better off than they had been when living in the country, and as they grew richer and better able to care for themselves and their children, it was their offspring that mostly survived the various bottlenecks. By the late 1700s the population of England was largely derived from the economic upper classes of the Medieval period. By studying documents from the period from 1200-1800, Clark shows how work hours steadily increased, literacy and numeracy levels rose, and the rate of interpersonal violence dropped. More importantly came a concomitant preference for saving over consumption. These behavioral traits slowly became embedded in the English population, and they stoked the furnace of the Industrial Revolution.

According to Clark, the peoples of industrialized nations such as England are substantially different from the peoples of hunter-gatherer societies as a consequence of this behavioral evolution in which the more affluent out reproduce their poorer neighbors, thus insuring the survival of the behavioral traits that gave rise to their affluence in the first place and, as a result, helping future generations to survive population bottlenecks. It is a fascinating hypothesis, and I am eagerly awaiting the publication of the book. Those who would like to learn more should check out this story at the New York Times.


Apollodorus said...

Genetic transmission of capitalist behavior, huh? Well, if anybody had managed to show that there is a genetic basis to specifically 'capitalist' behavior in the first place, then the idea might be plausible. I am certainly not one of those who thinks that human behavior has no significant foundation in biology, but I have a hard time believing that non-violence, saving money, and working long hours are anything but vastly underdetermined by genetics. How should we account for the widespread preference for saving and thriftiness among people who lived through the Great Depression, particularly when we observe that their children and grand-children do not share their concerns? Have genes become so thoroughly anthropomorphic that they know how to respond appropriately to complex changes in socio-economic circumstances?

I suspect that this aspect of the book will in fact be attacked as a sort of neo-fascist, ideological application of biology by people who think that any attempt to explain much about human beings by reference to biology must be something of just that sort. I doubt whether people will take it very seriously as a scientific claim, though, and so it probably won't raise as much a stink as Wilson's book. Then again, a complete absence of evidence has not stopped people from insisting that all kinds of behavior are genetically determined, so maybe people will take it more seriously than I imagine.

At any rate, the book as a whole sounds very interesting. I doubt whether society and culture can really be explained and understood without attributing a large and active role to practices and institutions, but this book promises to raise a lot of interesting questions about exactly what role they do play.

Scott Carson said...

Perhaps you'll feel differently once you've read the book, which I'm sure you plan to do as soon as it's published.

I imagine that the folks who lived through the depression were probably already displaying the selected behaviors, since the Industrial Revolution was by then largely over. That their grandchildren (or some of them, anyway) tend not to display the same traits hardly strikes me as a counter example: it seems rather a confirmation of the hypothesis that economic conditions (that is, environmental factors) can affect the behavioral traits of successive generations.

That behaviors are heritable seems to me to be beyond doubt, but you're right that in most cases causal explanations are massively underdetermined by the data. But not, I don't think, for the reasons you posit: there's no need, as far as I can see, for any discussion of "genetics" as such here, though it depends upon what you mean by that term and what sorts of things you want to include under the rubric of "genome". Based on what you write, it sounds to me as though what you have in mind is a fairly straightforward molecular notion, but that is an unduly restricted notion of "genome" for this sort of topic, and it would appear to unfairly beg the question against the hypothesis. I imagine that all we really need do to justify an evolutionary explanation for this behavior is to put together the sort of case that Clark has put together. Granted, it's fairly controversial evidence, but it's not wildly implausible, and to talk about the hypothesis as grounded in "a complete absence of evidence" strikes me as rather unfortunate posturing, given that all we know about it is what's been printed in the New York Times. In fact, based on the description there I would say that it sounds as though there is far more scientific evidence in Clark's book than in Wilson's, to be perfectly frank.

For what it's worth, nobody is saying, and nobody ever has said, that "behavior [is] genetically determined". What people say, and rightly, is that behavior is a phenotype like any other, a function of genotype plus environmental factors. As such it is heritable. If it is implausible to construct any evolutionary explanations at all for behaviors, then all of evolutionary biology totters on the brink of pointlessness, since the construction of evolutionary explanations for phenotypes and genotypes appears to be a large part of what that particular science is all about.

But perhaps you don't like evolutionary biology: it is a historical discipline after all and, as such, will always be open to charges of underdetermination.

Apollodorus said...

Maybe I've had the same experience with evolutionary explanations of behavior as lots of people have had with Christianity; all I've heard is the nonsense version, I don't understand the real stuff, and I mistakenly read the nonsense into the real stuff. Maybe.

The idea that seems implausible to me (and not only to me, but also to people like Stephen Jay Gould and Richard Lewontin, if I've understood them correctly) is that genes cause behavior in a very straightforward way; e.g., the presence of some gene or combination of genes X in an animal leads to the frequent display of behavior Y. So, e.g., some unspecified genetic combination might be alleged to cause aggressive behavior in males but not so much in females, or to cause us to feel sympathy for others and therefore not harm them, or whatever. Clearly no explanation could ignore the environment entirely, since aggressive behavior, sympathy for others, etc. occurs in certain contexts, is directed towards others, etc. Even still, plenty of people seem to want to say that there are genetic causes for behavior of this sort; the environment's role is to trigger a kind of response in the animal.

Now, I have no doubt that this sort of account works well in lots of cases. I have a hard time seeing how it is supposed to work in cases like 'saving money,' though, because a decision to save money, or a general tendency to prefer to save money rather than spend it, seems to depend on a fairly complex (though not necessarily accurate) evaluation of the context of one's actions. Even for people who save their money because they've been taught to do it, the whole process involves a lot of conceptual thought and consideration of a whole range of their actions. The fact that behavior is heritable doesn't seem to imply anything at all about its genetic basis; there is plenty of evidence that shows that much behavior is not biologically inherited, but taught. To show that it's genetic, one should be able to point to particular genes, right?

The genetic account seems, rather, to imply that the behavior of saving money, or at least the urge to do so, is a rather mechanical process; the requisite genetic material is present and active, so the person wants to save money rather than spend it. The requisite genetic material is present and acive, so a person has blue eyes. I have a hard time seeing these things as parallel. So, from what little I've read, did Gould and does Lewontin. The core of their critique of Wilson et al. (minus the evil neo-fascism part) was that it conceives of the relationship between genetics and behavior in an overly straightforward way; they argued instead that genetics accounts for what we can do, perhaps what we are predisposed to do on a very general level, but not what we actually do at any given moment. Again, it's possible that I've misunderstood them, too, and it's been quite a while since I've read anything of theirs. But I don't take myself to be raising any complaints more fundamental than those.

Your restatement of the view, though, makes it seem a bit less mechanical. If I've radically misunderstood how genetic explanations of behavior are supposed to work, then straighten me out.

And yes, I think I will actually read the book.

Apollodorus said...

One additional point: you're right that there seems to be a whole lot of evidence in Clark's book, and more than in Wilson's. From the review, though, that evidence does not seem to be evidence for the claim that the behaviors in question have a genetic basis. In fact, the review suggests that Clark offers little or no evidence for that particular claim. It's unlikely that his colleagues would describe the view as "maybe just not necessary" or "a speculative leap" if he had put forth solid arguments for it. Unlikely, but possible.

It might be worth pointing out that Clark's claim about 'genetics' does in fact seem to be that this "repertoire of skills and dispositions" like "thrift, prudence, negotiation, and hard work" were transmitted genetically and not culturally. People didn't learn to act in these ways; they were not lead by practical reason, social practices, institutions, or anything of the sort to actualize potentialities that they had all along. Rather, they were just naturally thrifty, hard working, and so on, while their forebears weren't. Surely this claim needs to be justified by concrete evidence of some genotype that leads to thrift, hard work, etc., when placed in the right environment. We can, as I understand it, provide concrete evidence of genotypes for phenotypes like eye color, skull structure, immunity to certain diseases, etc. Why can't we do the same for thrift, and if we can't, why should we find it plausible to treat behaviors like thrift, hard work, etc. as "phenotypes like any other"? This is what I mean when I talk about a complete absence of evidence. That claim isn't posturing; it's either a valid criticism that proponents of these sorts of explanation can't answer or it's a simple misunderstanding on my part. I'd be happy to know for sure whichever turns out to be true.

Darwin said...

I guess the question, then, will partly be: how heavily does the book rely on a purported genetic basis for the traits being discussed.

It seems to me that the descent issue could be key as a matter of education/training event without a genetic basis. Or there might be some combination of a genetic set of capacities paired with the cultural knowledge to make use of them.

I don't necessarily tend to be into explanations that try to attribute such complex systems strictly to genetics, but it wouldn't surprise me to find that they are highly heritable, and also that there may be some sort of genetic component.

I'd be especially interested to see what his counter-examples look like: cultures in which the values he finds in Britain seem to have difficulty taking root.

It's true that Gould (whom I generally enjoy) and others have come down very hard on the idea of these sorts of things having any biological basis -- but that may in part be because Gould was very personally invested in a tabula rasa view of humanity -- in part due to his political inclinations.

Certainly, it sounds interesting.

Scott Carson said...


You keep writing "genetic basis", but I don't see what that has to do with anything. Nobody says that there is any kind of "genetic basis" for behavior (at least, nobody sensible), and I don't really have any idea where you're getting the notion that Clark is speaking strictly about the genetic basis of the traits rather than the overall evolutionary strategy of the trait. What people say in cases such as this is what is virtually trivially true: behavior is a phenotype, and that means that behavior is a function of interactions between the genome and its environment.

Now, it's true that not all phenotypes evolve by means of natural selection: natural selection is only one mechanism of evolutionary change. But when the changes that take place in human behavior take place as a consequence of selection pressure, and when those changes result in differential reproductive success, that just is evolution of the trait.

So I'm not all that sure what the mystery in this particular case is supposed to be, other than the fact that, as usual, it will be hard to test any overly specific claims about just what environmental factor is causes precisely what change in behavior. I'll grant you that the stories that get told about cases like these sometimes come across sounding like "just so" stories, and there have been some rather egregious failures that have made some a little shy to advance such explanations (for example, attributing criminal behavior to the double-y chromosome when in fact it seems rather to be connected with lower intelligence). But overall, I just don't see the problem.

It seems to me that folks generally have a little difficulty thinking of something like "a propensity to save rather than to party hearty" or "a propensity to altruism rather than Calliclean personalism" as a phenotype, and that it is merely this difficulty that stands in the way of taking Clark's thesis seriously.

Apollodorus said...
This comment has been removed by the author.
Apollodorus said...

Maybe you and I didn't read the review in the same way. I'm reacting particularly to this paragraph:

Dr. Clark says the middle-class values needed for productivity could have been transmitted either culturally or genetically. But in some passages, he seems to lean toward evolution as the explanation. “Through the long agrarian passage leading up to the Industrial Revolution, man was becoming biologically more adapted to the modern economic world,” he writes. And, “The triumph of capitalism in the modern world thus may lie as much in our genes as in ideology or rationality.”

As I understand this, Clark is claiming that the behaviors to which he attributes the social and economic change might have evolved culturally or genetically. If they evolved culturally, then they were learned behaviors that took root among the upper classes, whose descendants continued to behave in those ways after they had gone on to make up the lower classes. If they evolved genetically, then the behaviors were not so much learned as genetically based. In other words, thrift, hard work, and the like were not behaviors that were more or less equally possible for all of the people and actually cultivated by some, but behaviors that one group of people displayed because they had the necessary genes and the others didn't. I might be making mistakes here, but surely you can't claim that my interpretation has no basis in the review.

I'm quite frankly mystified by your claim that nobody sensible claims that there is a genetic basis for behavior. If you mean that nobody claims that behavior has nothing to do with the environment, then sure. Yet the whole controversy surrounding evolutionary psychology has to do with the extent to which human behavior is genetically based and how well genetics and evolutionary modes of explanation generally account for behavior. You might want to argue that the critics misunderstand EP or that nobody sensible buys EP and that the controversy is therefore irrelevant. But denying legitimate controversy isn't the same as denying controversy altogether. So I really don't know what your denial is supposed to mean.

Let me be clear, as I may not have been, that my skepticism here is not directed at the applicability of evolutionary modes of explanation to the phenomena that Clark discusses. It is directed instead to the claim that these behavioral changes are to be explained in some non-trivial way by genetics. The rest of Clark's account seems far more plausible.