Arnold Kling  

The Demographic Transition

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Bryan writes,


The puzzle of declining family size in the face of rising wealth remains.

Since I'm currently steeped in Gregory Clark, let me throw in my two cents.

From Clark, we learn that in England:

1. Prior to the industrial revolution, the number of (surviving) children was higher for people with higher incomes. Clark describes this--misleadingly, in my opinion--as greater fertility among the rich.

2. Population exploded from about 1750 to about 1890.

3. Around 1890, the "demographic transition" set in, and people started having fewer children.

My model of this is that parents want heirs, not children. Until the industrial revolution, you had to have a lot of children in order to make sure that some would survive. On p. 92, Clark writes,


from 1580 to 1800 18 percent of infants died within the first year. Only 69 percent of newborns made it to their fifteenth birthday.

My explanation for the three facts above is as follows.

1. Rich people had more surviving children because they were able to take better care of children. There need not have been more births among the rich--just fewer childhood deaths.

2. With the Industrial Revolution there came a drop in childhood mortality, which took parents by surprise. For a few generations, people had more surviving children than they expected.

3. Once people were used to lower childhood death rates, they cut down on the number of children they decided to have.

I said that Clark's book could spawn a lot of Ph.D dissertations. Proving or disproving my conjecture could be one of them.


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COMMENTS (12 to date)
spencer writes:

When I studied economic development and economic history in the 1960s what you are saying was standard economics. As far as I know it has always been standard economics. Essentially every developed country has gone through this process and it is still occurring if you look at the drop in the birth rates in countries like India in recent generations.

spencer writes:

When I studied economic history and economic development in the 1960s what you are saying was standard economics. As far as I know it has always been standard economics. How did Caplan mange to get a PhD in economics without learning this.

Bruce G Charlton writes:

Until a variety of safe, acceptable and accessible contraceptive and abortion technologies had been developed - parents could not *decide* how many children to have.

Except by refraining from sex, which has never been popular.

Indeed, it is likely that some societies never understood the link between sex and babies - it is rather delayed and unpredictable, after all.

Tim Worstall writes:

Arnold,
That, roughly speaking, has been my own theory on the transition for some years now. There's a couple of paras on it here:
http://www.tcsdaily.com/article.aspx?id=092206B

Josh writes:

Arnold,

I agree with Bruce Charlton. I think it's entirely possible that "choice" is not a large factor. I think contraception and abortions have probably played the biggest part. The drop in birth rates in the West seems to coincide with the availability of these technologies, as well as their social and religious acceptance. And even in rich societies, religious groups who are forbidden to use them seem to have larger than average families (or is that just a stereotype?).

Cyrus writes:

1. Rich people had more surviving children because they were able to take better care of children. There need not have been more births among the rich--just fewer childhood deaths.

Insofar as historical demographers have been able to measure it, the upper classes in medieval and early modern Europe did not experience lower child mortality. A few historians have even concluded that the data show that the wealthy experienced greater child mortality. Among other proposed culprits: the wealthy did less breast feeding, or at least hired it out.

Karl Smith writes:

In the absence of birth control fertility can be controled culutrally by:

Delaying marriage and loss viginity

Increased duration of breast feeding

Of course there is always abstience during marriage. There is at least anecdotal evidence that this increased in England during the Victorian Era.

The Frigid wife theory was born then, etc.


However, it could be simple evolution. Suppose the child death rate among couples who had few children fell much faster than the death rate among those who had many.

Indeed, in the city it might not be unreasonable to expect that the death rate for two or three child couples fell while the death rate for five six child couples increased.

In that case future generations would come to be dominated by people who have few children. Even though they are birthing few children they are suriving, more children. If the population exploded rapidly this could happen in a few generations.

What we are seeing then is not a change in behavior of types but a change in the frequency of types.

ed writes:

The "demographic transition" happened in France decades before everywhere else (including rural France). Birthrates were already sharply declining in the first half of the nineteenth century.

Lord writes:

In the pre-industrial era, more children meant more mouths to feed, but more hands to do the work. The industrial era made child labor less valuable while providing more options for consumption.

Steve Sailer writes:

Europe typically had lower fertility than China, due to later marriage and more people going into convents. So, population in China grew quickly to whatever the technology of the time could support under good government. But when public order broke down, there would be huge die offs as in the 1850s, which were much rarer in Europe, where population was more stable.

Matt writes:

It is a push-pull effect, parents have a longer outlook for their children, but social institutions incorporate this longer outlook in greater "rent" for expansion of social structure.

In term of social development, industrial specialization yields large social organizations yields greater income transfer from families to specialized services, which limits available income for larger families.

Over time, a transfer of sovereignty from the family to the larger economy.

Garett writes:

Arnold, It's worth emphasizing that your three facts are entirely consistent with an increase in IQ among British elites...especially point 1:

"Rich people had more surviving children because they were able to take better care of children. There need not have been more births among the rich--just fewer childhood deaths."

From the point of view of evolution, whether the offspring of the rich make it to the point of being born per se is irrelevant (although Clark mentioned in a seminar at UC Berkeley that the British parishes kept remarkable records of births and deaths of infants).

What really matters is whether the offspring of the rich survive to have babies of their own....and by Clark's evidence, the answer appears to be that yes, they did survive in greater numbers, leading to a shift in the gene pool in favor of the genes of the rich.

As Clark notes, the British people of today are largely the descendants not of the peasants of the middle ages, but of the elites....

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