Fertility decisions and the escape from slavery

by on January 5, 2014 at 5:58 am in Data Source, Economics, History, Law, Uncategorized | Permalink

Hope really does matter, as outlined in a recent paper (pdf) by Treb Allen of Northwestern, with the formal title “The Promise of Freedom”:

This paper examines the extent to which the fertility of enslaved women was affected by the promise of freedom. Because women derived greater pleasure from children when they were free, increases in the distance to freedom (which lowered the probability of escape) should reduce fertility. Exploiting the Fugitive Slave Law of 1850 and the particularity of U.S. geography, I demonstrate a strong negative correlation between fertility and the distance to freedom. This negative correlation is stronger on larger plantations, but disappears when the father of the child is white. The correlation varies with the difficulty of the route, and a similar correlation is not present for white children or for slave children born prior to the Fugitive Slave Law. The negative correlation suggests that despite the small number of successful escapes, the promise of freedom played an important role in the everyday lives of slaves.

There are more interesting papers by Allen here., including on the gravity equation and location theory.  Allen is one of the most interesting young economists today, yet he remains undercovered.  Here is Treb on “Equilibrium distribution of population if the surface of the world was shaped like a cow.”

1 Steve Sailer January 5, 2014 at 6:51 am

Maybe, but this may have had more to do with the type of crop, which varied by latitude — tobacco most northerly, cotton in the middle, and sugar the farthest south — and with plantation owners’ economic incentives.

Women could work in the fields or be heavily pregnant or nursing, but not both. Plantation owners could provide incentives and conditions that would tip the balance one way or another.

Sugar-raising tended to be brutal (e.g., Jim in “Huckleberry Finn” is terrified of being sold down the river to Louisiana).

Cotton was in the middle, and tobacco (Virginia and North Carolina) was the easiest: lots of delicate indoor work.

But raising tobacco tended to exhaust the soil. It was not a boom crop like cotton was in the 19th Century.

Plus, the growing season was shortest the closer you were to the Mason-Dixon line, leaving lots of of down time during the winter.

Also, the northern slaves states were the healthiest. Africans were more resistant to warm-weather diseases than whites were, but fevers still took a greater toll farther down south. While whites were healthiest in Massachusetts, blacks were healthiest around Virginia.

So it was widely noticed in mid-19th Century accounts that the most profitable output of Virginia tobacco plantations was not tobacco, but slaves. The demand for slaves was high in the burgeoning cotton belt, so it was in Virginia slaveowners’ economic interest to encourage fertility.

See Fogel and Engerman’s “Time on the Cross” and Genovese’s “Roll, Jordan, Roll” for documentation.

2 white radical blogger January 5, 2014 at 7:15 am

steve sailor wrote:
“So it was widely noticed in mid-19th Century accounts that the most profitable output of Virginia tobacco plantations was not tobacco, but slaves. ”

Indeed. According to Dr Tenzer’s book THE FORGOTTEN CAUSE OF THE CIVIL WAR, the price for near-white (high yella) female slaves under the one-drop rule was over 2000 dollars. That was how much the new orleans bordellos would pay for white-appearing female slaves. So the white slaveowners (as opposed to the fairly high percentage of nonwhite slaveowners (about 5% according to the 1860 census, IIRC)) were breeding their high-yella female slaves as a product to be sold, evolving them towards whiteness. The whiter the female slave, the higher the price paid by the bordellos.

In fact, tenzer quotes one survey conducted that showed that about 5-10% of all slaves appeared near-white.

Anyway, the anti-abolitionists got hold this fact and used it in the anti-abolition porn. The whites up north then got scared that the slaveholders were going to enslave them, too. In fact some slaveowners did want to enslave whites (“Capital Shall Own Labor!” was their rallying cry). So that was the forgotten cause of the civil war. Now it has been shoved down the memory hole because it does not fit The Narrative. These facts have been “unnaturally selected” for extinction in the American Meme Pool….

3 dead serious January 5, 2014 at 10:10 am

Always trust a history lesson from someone who chooses the name “white radical blogger.”

4 A Definite Beta Guy January 5, 2014 at 11:04 am

I have learned more from the radicals than the main-stream, who drove a man from the world’s most prestigious university position because he suggested there might be a variation in intelligence between the sexes in a sexually dimorphic species.

5 dead serious January 5, 2014 at 7:40 pm

Truthers and evangelicals have their own versions of history widely divergent from those of “the elite” and I tend to pay them no never mind.

Your chosen handle signals an agenda that immediately makes me skeptical.

Posting under the handle “angry black militant” would have a similar effect. On me, anyway.

6 white radical blogger January 5, 2014 at 2:56 pm

it is accepted that the chinese and russian power structure manipulated history in order to present their side favorably. But the American power structure would never do such a thing. We trust our power elite. They would never do wrong. Right?

7 Steve Sailer January 5, 2014 at 8:06 pm

History is supposedly written by the victors, but almost all the history books and historical novels about the Civil War and Reconstruction were written by Confederate sympathizers for most of a century afterwards. Why? Because Southerners cared more and invested in writing (and rewriting) Civil War / Reconstruction history.

History is written by the writers of history books.

8 Steve Sailer January 5, 2014 at 8:48 pm

These days, Quentin Tarantino is a more influential historian of slavery than Robert Fogel, but it’s worth reviewing Fogel’s obituary in the NYT:

Robert W. Fogel, Nobel-Winning Economist, Dies at 86
Published: June 11, 2013

Robert W. Fogel, a Nobel-winning economist whose number-crunching empiricism upended established thinking, most provocatively about the economics of slavery, died on Tuesday in Oak Lawn, Ill. He was 86.

His death was announced by the Booth School of Business at the University of Chicago, where he had been a distinguished professor. He lived in the Hyde Park section of Chicago.

Professor Fogel, a rumpled former New Yorker by turns amiable and combative, was widely known for work that aroused objections if not open hostility in academic circles, chiefly through his pioneering use of cliometrics, which applies economic theory and statistical methods to the study of history. (Clio was history’s muse in Greek mythology.)

He first came to prominence in 1964 … But it was the publication 10 years later of “Time on the Cross,” a two-volume study of slavery, written with Stanley L. Engerman, that propelled Professor Fogel into the critical spotlight and instant celebrity.

They contended that slavery had not been, as widely portrayed, an inefficient system destined for collapse, with slaves living in virtual concentration camps and worked to death.

Rather, after studying medical records, cotton yields and other data, the authors argued that slavery had been highly efficient in utilizing economies of scale and that plantation owners had regarded workers as economic assets whom they were inclined to treat at least as well as livestock. This tended to limit exploitation, Professor Fogel and his colleague found, declaring, in fact, that slave life in the South was generally better than that of industrial workers in the North.

An intellectual firestorm resulted. Some critics accused Professor Fogel, who was married to an African-American woman, of being an apologist for slavery, though he and Professor Engerman had been explicit in acknowledging that slaves had been exploited in ways not captured by statistical data.

Despite the attacks, the authors did not budge from their findings and their main point — that slavery would not have ended without the Civil War….

Professor Fogel received the Nobel in economic science in 1993, sharing it with a fellow cliometrician, Douglass C. North. The Royal Swedish Academy of Sciences cited Professor Fogel for clarifying railroads’ role in American economic development and the economic role of slavery. …

Many of Professor Fogel’s findings have achieved broad acceptance, but criticism of the slavery work was intense. (Professor Goldin said many of the attacks came from people who had not read “Time on the Cross.”)


9 david January 5, 2014 at 6:58 am

Conversely, if escape is more likely, young children are more likely to tie your slave down.

10 Steve Sailer January 5, 2014 at 7:08 am

Good point. If you owned a plantation ten miles south of Pennsylvania, it would make sense to encourage your slaves to put down roots.

Similarly, in modern America there are a lot of jobs where the bosses encourage the employees to acquire wives, kids, and mortgages so they can’t just up and quit because they’re sick of the rat race.

11 Randy McDonald January 5, 2014 at 2:34 pm

Is there any way to do that if the slaves aren’t cooperating?

I suppose that slavemasters might order the rape of female slaves.

12 Vernunft January 5, 2014 at 7:59 pm

How many female slaves have such a dysgenic predilection that they’re not going to engage in reproductive sex at all?

13 Steve Sailer January 5, 2014 at 8:19 pm

“Is there any way to do that if the slaves aren’t cooperating?”

It’s called doing what comes naturally.

14 Marie January 5, 2014 at 10:58 am

Or, another take, if you have more children you are more motivated to try to improve your life and the lives of your children, and not be separated for them. Instead of the hope of freedom increasing fertility, increased fertility could raise the urgency of the desire for freedom.

15 Steve Sailer January 5, 2014 at 7:03 am

Anyway, it seems backwards to suggest that the rational response to a higher chance of escape was to have children, what with crying babies being an obvious impediment to hiding out silently from patrols, breathing through a reed underwater, and hopping from ice floe to ice floe across the Ohio River.

Further, “a similar correlation is not present for … for slave children born prior to the Fugitive Slave Law” also seems backwards. The whole point of the Fugitive Slave Act of 1850 was to make it harder to escape by allowing southerners to chase fugitive slaves in northern states, so why would passage of the law make proximity to the border with the north more encouraging?

I suspect the huge cotton boom of the 1850s is a better explanation: slave women in the cotton belt of the deep south states were probably worked harder in the fields in the 1850s due to the huge profits to be made from cotton, depressing their fertility. Meanwhile, there wasn’t as much of a boom in the 1850s in tobacco, corn, and other upper south crops, so slaveowners encouraged their slaves to have children, whom the owners could sell.

16 mike January 5, 2014 at 12:52 pm

The paper also notes that certain chemicals present in cotton depressed fertility, and women working on cotton plantations would apparently chew the root as a form of birth control.

17 Steve Sailer January 5, 2014 at 7:09 am

Toni Morrison’s “Beloved” is probably not a reliable guide to economic history.

18 Steve Sailer January 5, 2014 at 7:18 am

Yup, I was right about the inspiration for this paper. Here’s footnote 2:

“2 Margaret Garner’s plight provided the inspiration for the novel Beloved by Toni Morrison”

Morrison is an okay fiction writer (they gave her the Nobel), but Time magazine used to hire her occasionally to write columns in the 1990s, and she had to be close to the all-time worst nonfiction essayist. As illustration, here are a couple of her nonfiction titles, complete with that surfeit of punctuation that is the secret handshake of postmodern lit theory academics:

Race-ing Justice, En-gendering Power: Essays on Anita Hill, Clarence Thomas, and the Construction of Social Reality (editor) (1992)

Birth of a Nation’hood: Gaze, Script, and Spectacle in the O.J. Simpson Case (co-editor) (1997)

19 dearieme January 5, 2014 at 9:12 am

But it never was shaped like a cow: he means “were” shaped like a cow.

20 FC January 5, 2014 at 3:14 pm

What, you don’t accept cowtastrophism?

21 Tom T. January 5, 2014 at 11:27 am

“increases in the distance to freedom (which lowered the probability of escape) should reduce fertility.”

One gets the distinct impression that Prof. Allen does not understand how babies are conceived.

22 Randy McDonald January 5, 2014 at 2:33 pm

I suspect that the professor is working from the assumption that people living in slavery are going to be reluctant to produce children also living in slavery.

There is some evidence of this in the history of African slave populations in the New World, which were never self-sustaining and required constant shipments of new slaves to avoid collapse, although mortality seems to have been the dominant factor there.

23 david January 5, 2014 at 5:33 pm

Did female slaves really have substantial power over fertility decisions? Rape seems to have been a matter-of-fact practice.

24 Randy McDonald January 5, 2014 at 5:49 pm

Not having complete control doesn’t mean not having some control. The use of chewed cotton stems as primitive contraceptives is mentioned above.

25 Steve Sailer January 5, 2014 at 8:16 pm

No, that’s largely another myth — see Genovese’s “Roll, Jordan, Roll.” The opening scene of “The Butler,” for example, is preposterous.

Slaves were well-armed to take retribution on masters who violated norms with all the edged tools on the plantation — axes, claw hammers, etc. Plantations were big places where something bad could happen to individuals who had committed outrages. On large plantations, several slaves usually even owned rifles for hunting.

If you look at the genetic data, it’s obvious that over 95% of children born to black women in American history were fathered by black men. The average African-American is about 20% white, and the average black’s average ancestor has been in America perhaps 12 generations, so 20% / 12 * 2 implies that 29 out of 30 babies born to black women were fathered by black men.

And the notion that all the black women who did have children with black men were raped is just lowbrow dogma — do you think Sally Hemmings wasn’t the least bit attracted to Thomas Jefferson?

26 Steve Sailer January 5, 2014 at 8:36 pm


And the notion that all the black women who did have children with white men were raped is just lowbrow dogma …

27 Steve Sailer January 5, 2014 at 8:35 pm

“There is some evidence of this in the history of African slave populations in the New World, which were never self-sustaining and required constant shipments of new slaves to avoid collapse, although mortality seems to have been the dominant factor there.”

While that was true for, say, Brazil during the Slave Trade era when it was cheaper to work male slaves to death in sugar plantations, no, the slave population of the United States was growing rapidly through natural increase after the Slave Trade was abolished. The international slave trade was outlawed by Congress in 1808 and the Royal Navy started cracking down on it in 1818, so let’s use the 1820 U.S. Census as the baseline at the end of the Slave Trade. In 1820, there were 1,772,000 blacks in the U.S., free and slave. By the 1860 Census, there were 4,442,000 blacks.


In the South from 1820 to 1860, the black population grew 149% and the white population grew 153%, overall. If more of the increase of whites was due to immigration, then the black rate of natural increase in the South might have been higher.

28 athEIst January 5, 2014 at 8:16 pm

Miscellaneous is right! WTF( the cow). Anyone care to tell me WTF!

29 athEIst January 5, 2014 at 8:19 pm

BTW dearieme, absolutely right. This definitely calls for the subjunctive/

30 zbicyclist January 5, 2014 at 11:38 pm

Another factor: German immigration was very heavy during the decade 1851-1860, and particularly strong in and near border states (Ohio Valley, upper Mississippi Valley). German immigrants tended not to be supporters of slavery. This was one factor keeping Kentucky and Missouri from becoming completely confederate states.

1820-1840 160,335
1841-1850 434,626
1851-1860 951,667

The point being that there’s a lot more than just the Fugitive Slave Law of 1850 going on, and this is at least one factor that’s correlated with distance to the free/slave border.

31 Ed January 7, 2014 at 6:21 pm

I could have sworn I read somewhere that US Blacks are the only Blacks brought to the New World that have always had a positive natural replacement rate. Thus making importation of slaves from Africa less important than it was in other colonies.

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