August 05, 2009
Fertility Decline With Rising Incomes Reverses At High Incomes

More money does not mean fewer babies indefinitely.

PHILADELPHIA – A team of researchers at the University of Pennsylvania and the Università Bocconi in Milan have released a study that challenges one of the most established and accepted standards in the social sciences: Human fertility levels tend to decline as countries advance towards high levels of social and economic development.

The researchers question the conventional wisdom by documenting new findings, potentially relevant to discussions of economic and social policy, of a reversal of fertility declines in highly developed countries once they reach a certain level of wealth.

The study, "Advances in Development Reverse Fertility Declines," by Hans-Peter Kohler and Mikko Myrskylä of Penn's Populations Studies Center and Francesco C. Billari of the Università Bocconi, is published in the current issue of the journal Nature.

I am not surprised by this result. Children can be viewed as luxury consumption goods. You can show your high status by living in a big house and raising lots of children.

If this trend holds up then world population might not peak at only 9 billion people.

Researchers looked at total fertility rate and the human development index, HDI, in 24 developed countries during a 30-year period. The data demonstrated that the well-established negative relationship between fertility and development has been reversing as the global population entered the 21st century. While social and economic development continues to promote fertility decline at low and medium levels of HDI, at advanced HDI levels further development can reverse the declining trend in fertility.

I also expect the reversal of fertility decline to happen as a result of natural selection. People who carry genes that make them more friendly toward the idea of making babies will pass along those genes to more offspring.

Update: What I'd like to know: Did the researchers study the effects of immigration on fertility? Poorer immigrant populations have higher fertility. In fact, Mexican immigrants in the US who get amnesty have higher fertility than Mexicans in Mexico. So US immigration policies are boosting overall world fertility.

Share |      Randall Parker, 2009 August 05 10:48 PM  Trends Demographic

Mthson said at August 6, 2009 1:15 AM:

Is some portion of this fertility boost derived from high HDI nations attracting larger amounts of high-fertility immigration?

OneSTDV said at August 6, 2009 7:11 AM:

Somewhat off-topic but pertinent to Futurepundit and Parapundit:

Robots are starting to be implemented in Japan for service positions. This could have grave consequences for America if both dysgenic fertility and low-IQ immigration continue.

How Automation Systems will Interact with Dysgenics and Immigration

kurt9 said at August 6, 2009 11:46 AM:

There is a slight uptick in native fertility with increased income. But it is not that significant. It appears that the fertility does go back up, but does not exceed 2.0 in most cases. Nonetheless, social conservatives who fret about the birth dirth should experience some relief over this.

David Govett said at August 6, 2009 1:01 PM:

Japanese population peaked last year, as I recall, and children have moved from the farms to the cities, so nobody left to care for elderly. Japan has a huge and burgeoning elderly population. Robots are better than nothing, I suppose.

One STD said at August 6, 2009 2:20 PM:

"Robots are starting to be implemented in Japan for service positions. This could have grave consequences for America if both dysgenic fertility and low-IQ immigration continue."

Um how? Are you saying that the Japanese are going to blow America away now that they spend less time doing dishes? Or that the mere act of researching robots will magically increase their collecive IQ to the point of becoming space aliens?

They're investing in robots cause they have to. No businessman is gonna say to himself "Oh gee, this autovat robot only costs $150,000, does three specific things and needs a $30/hr mechanic to nanny it once a month. It's sooo much better than some cheap human that's desperate for a job." This is pretty much the reason why America shrugs at most robotics in the service sector. Also industrialized services often leave the customer feeling unloved, much like getting restaurant food from a soda machine.

Even if Japan creates useful robots that we can buy, like say one that trims the hedges, the poor dumb people that used to do the job will just be ranched together with their brethren in commission based sales if they don't flee to Mexico. America is good at using people who have nothing but a wing and a prayer.

averros said at August 7, 2009 2:37 AM:

Wealthy people can have children without suffering much inconvenience - they have big houses and can easily hire all the help they need, and can afford the best care and education for their children. They are K-strategy types.

Poor people simply don't care much about their kids (or anything else). They produce lots of them and then don't spend much money and efforts on raising them. They are r-strategy types.

The middle class is fucked by the taxes and the need to run in the rat race. So they defer having kids until they can afford them. Which is too often, never.

Clarium said at August 7, 2009 5:53 PM:

Well, in Sweden, you do not need to run the rat race; they keep unemployment down by putting people away in make-work programs and on "early retirement".

Also Steve Sailer pointed that Sweden has a higher birthrate than Italy and Spain because they can afford a welfare state where women could work and put their children in daycare.

THe automation post isn't that insightful because it is already something that I appreciate. Automation would actually make society poorer by increasing restlessness. I suppose the best way to deal with it is to copy Sweden and have make-work jobs. averros... remember when you posted the article "The Sweden Myth." Actually, that article made me love Sweden even more when I heard about their "labor market political activities" used to reduce the unemployment number. Stefan Karlsson accurately presented the information in the article though even though it made me love Sweden more while it was anti-Swedish article.

Clarium said at August 7, 2009 6:00 PM:

Does anyone have any information on black fertility in the 1970s (particularily in places such as Detriot)? Has it increased since then? Has the zero-sum nature of globalization made blacks more "r" like?

Randall Parker said at August 7, 2009 7:56 PM:

One STD,

The Japanese will bring down the cost of robots for housekeeping and other manual labor tasks. This will reduce the demand for house cleaners, lawn care services, and other manual labor jobs. Then the low skilled immigrant populations will be out of jobs and we'll have to deal with the consequences.

Clarium said at August 7, 2009 8:18 PM:

I suppose European countries will benefit from the automation of housekeeping since few people do those tasks in countries such as Germany and Sweden because wages are high due to unions and employment laws. Maybe governments can pass laws to ban (or tax) the automation of some jobs, but allow housekeeping tasks such as painting a house, lawncare, cleaning, to be automated.

Regarding my question about black fertility; does losing jobs increase short-term discount rates since those blacks correctly assume their future isn't that bright, so they switch to hedonistic activities such as drug use and sex? If so, then make-work jobs are one way to correct this (also immigration restriction and trade restriction also work.) In a way, make-work jobs have a positive impact.

kurt9 said at August 9, 2009 3:43 PM:

One way is to churn out offspring in large numbers, turn them out into an uncaring world, and hope that one or two of them make it. The other is to have but a few progeny and to dote on them, ensuring that they grow up with every possible advantage for the ensuing struggle with their peers for mates and resources. The former is characteristic of species that live in unstable environments and the latter of species whose circumstances are predictable.

The former is an example of barbarism whereas the latter is an example of civilized behavior. Parental investment is one of the defining characteristics separating intelligence from animals.

Randall Parker said at August 9, 2009 4:12 PM:


Once sperm and egg selection for high IQ and other traits becomes possible some small fraction of the population will be capable of making a dozen genius babies per couple. I wonder if any couples with the right genes will opt to do this.

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