Arnold Kling  

The Malthusian Trap

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Tyler Cowen chews, but does not swallow, a new paper by Greg Clark. Clark writes,


we can test empirically whether the average person in 1800 was any better off than the people of 10,000 BC on any dimension, and the answer is no.

I've seen other economists suggest that the escape from the Malthusian trap began in 1500. Most economists believe that populations everywhere have escaped the trap by now, but I gather that Clark thinks that the populations of sub-Saharan Africa are deeper in the trap than ever.

But here is where Tyler starts having indigestion: Clark writes,


In the Malthusian era on average every woman could have only two surviving offspring. But these two had to be selected by some mechanism from the average of 5 children each women had in the pre-industrial era. And as long as mothers and fathers varied in their characteristics this survival process favored some types of individuals over others. The Darwinian struggle that has shaped human nature did not end with the Neolithic Revolution, but continued indeed right up to 1800.

Clark proceeds to say that from roughly 1250 to 1800 in England, the rich reproduced more successfully than the poor. This tended to breed capitalist values into the population.

One interesting implication is that with a relatively stable overall economy, greater reproductive success at the top means that there has to be a lot of downward mobility intergenerationally. Clark claims to find evidence of such downward mobility.

The key argument:


Interest rates fell from astonishingly high
rates in the earliest societies to close to low modern levels by 1800. Literacy and numeracy increased from being a rarity to being the norm. Work hours rose between the hunter gatherer era to modern levels by 1800. Finally there was a decline in interpersonal violence.

Clark claims that these changes were due to natural selection of personality traits, rather than institutional changes. I would think that if this were true, one would tend to find smooth, exponential improvement. If institutions were important, one would be more likely to see jumps and plateaus.

Finally, as Tyler points out, arguing that selection pressures operated more strongly in England than in, say, Italy, is going to be difficult.


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TRACKBACKS (2 to date)
TrackBack URL: http://econlog.econlib.org/mt/mt-tb.cgi/650
The author at The Free Thinker in a related article titled The Malthusian Miserabilist Fallacy writes:
    A new paper by economist Gregory Clark (hat tip: Arnold Kling, Tyler Cowen) recites a bit of conventional wisdom about economic history:The basic outline of world economic history is surprisingly simple. Indeed it can be summarized in one diagram... Be... [Tracked on February 14, 2007 12:15 PM]
The author at The Free Thinker in a related article titled My Favorite Quote From Adam Smith writes:
    From Chapter I of the Wealth of Nations, the text traditional credited with being the founding text of the discipline of economics:Observe the accommodation of the most common artificer or day-labourer in a civilised and thriving country, and you will [Tracked on February 15, 2007 12:14 AM]
COMMENTS (7 to date)
mjh writes:
Clark claims that these changes were due to natural selection of personality traits, rather than institutional changes. I would think that if this were true, one would tend to find smooth, exponential improvement. If institutions were important, one would be more likely to see jumps and plateaus.
A principle in evolution called Punctuated Equilibrium says that natural selection doesn't produce steady changes. Instead, "when evolution does occur, it happens sporadically (by splitting) and occurs relatively quickly." So what you have with biological natural selection is jumps and plateaus.

In other words, jumps and plateaus might not be a good indicator for ruling out natural selection.

William Newman writes:

Someone (I can't find a name...) wrote "A principle in evolution called Punctuated Equilibrium says that natural selection doesn't produce steady changes. Instead, 'when evolution does occur, it happens sporadically (by splitting) and occurs relatively quickly.' So what you have with biological natural selection is jumps and plateaus."

It is strange to call P.E. a "principle" of evolution; P.E. is a pattern which is consistent with the usual ideas of evolution and genetics *and* some additional conditions, and it is controversial how important it is in practice even over periods of geological time when those additional conditions are likely to be met.

As I understand it, one of the big additional conditions in the most usual version of punctuated equilibrium is isolation of small subpopulations. (Search for the string "isolate" in the Wikipedia article to see some of what I mean.) Europe was isolated from the Americas, but what small populations within Europe were genetically isolated for many generations? If you don't have some in mind, saying that "A principle in evolution called Punctuated Equilibrium says that natural selection doesn't produce steady changes" seems to be almost completely mistaken: it's not a principle, its usual necessary condition of isolated subpopulations doesn't apply in medieval Europe, and search for "cm" in the article to see what "relatively quickly" means: 30 generations is not a lot for a radical change of the sort the theory was developed to explain.

That said, there might be time in there for intense breeding pressure to spread new genes in England: I bet black plague resistance genes could have been several times more common in 1600 than in 1200, for example. But *that* said I doubt genetic changes explain many of the observed differences, and I especially doubt it in violence. In violence, the historical change is very large, and if genetic change were anywhere near as important as institutional and contagious cultural change, I'd expect genetically non-English subpopulations in modern England and English-colonized regions to shine like a supernova in violence statistics, many times more violent in a pattern persisting even in cancel-the-environment situations like infant adoptions. AFAIK, they don't (and if they did, it would be odd that that fact is not to making the rounds arm in arm with the theory).

Steve Sailer writes:

Steady progress is fairly evident in English society over this period. High level clashes could slow economic growth, but when the top people finally got the basics nailed down, as with the permanently "settled distribution of property" in 1688, society as a whole was ready to move forward quickly.

Nathan Smith writes:

Just because a population is stuck in a Malthusian trap, it does not follow that its welfare is not improving. There is a conceptual problem with the notion of "subsistence."

In order to survive, we require, not some unitary "utility," but a wide range of goods. Let's call them x1, x2, x3, etc., and define 1 unit as the minimum needed for survival.

Suppose that in 1000 AD a population possesses, on average, 1 unit of x1 per head, 2 units of x2, and 5 units of x3. In 1500 AD, the population possesses 1 unit of x1 per head, 5 units of x2, and 20 units of x3.

In a sense, the population is at subsistence in both 1000 AD and 1500 AD. An economist might observe that at both dates, any fluctuation in the amount of x1 available would lead to destitution of death for part of the population. The population would in this sense be in a Malthusian trap, and it may well be that those dying of starvation would not be much comforted by the fact that they had more x2 and x3 than their ancestors did.

But at least for those who manage to keep their x1 at 1 unit or above, they would clearly be better off than their ancestors.

The somewhat simplistic idea of "utility" is certainly helpful in many cases and has a cogent theoretical basis in the assumptions of transitivity, completeness, etc. of preferences. But it has its flaws, and must be handled carefully. It has betrayed Clark into an invalid line of argument.

US writes:

I don't see why the rich would have been more capitalist than the poor during that period? Weren't two of the main reasons why they were rich in the first place feudalism and mercantilism, ie. protected trade? Why would the successful reproduction of a rich minority, who for centuries had enjoyed the benefits of protected trade, make the country as a whole more capitalist?


@Nathan: If such a model were to hold, it would have to be a policy-induced trap. If there were no trade barriers, what would prevent the starving population in your model from trading their excess x2 and x3 for one unit more of x1 from foreigners (or parts of the population who had more than one unit of x1)? Supply and demand would make such a model unstable in the long run. And I doubt Sudan and Somalia produce a lot of x2 and x3. They just don't produce much at all.

Fundamentalist writes:

Actually, the industrial and commercial revolutions began in the Dutch Republic. Check out "The First Modern Economy: Success, Failure, and Perseverance of the Dutch Economy, 1500-1815" by Jan de Vries, "The Dutch Republic" by Jonathan Israel and "The Disciplinary Revolution: Calvinism and the Rise of the State in Early Modern Europe" by Philip S. Gorski.

Also, the Dutch were the first to escape the Malthusian trap.

As for the wealthy having capitalist tendencies, all histories I have read say just the opposite. The wealthy throughout the middle ages and early modern period engaged in conspicuous consumption and opposed new technology and methods. They inhibited capitalism. Capitalism took off in the Dutch Republic among the merchants and small scale manufacturers, not the wealthy nobility. By the early 17th century, these merchants and manufacturers had become wealthier and more numerous than the nobility.

mjh writes:

William Newman: I wrote that. My point in writing it wasn't to get sidetracked into a discussion about evolution, or any controversy over PE. My point was to suggest that PE might be evidence to not expect absolute evenness in evolutionary processes. As a result maybe Arnold should re-examine this test:

Clark claims that these changes were due to natural selection of personality traits, rather than institutional changes. I would think that if this were true, one would tend to find smooth, exponential improvement. If institutions were important, one would be more likely to see jumps and plateaus.

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