Primogeniture and Fertility

The practice of passing all property
to one’s firstborn son.

A man with four sons has an estate. He dies. To whom goes the land?

Today, it would be split between the four sons evenly, by law. In the past, there was a practice known as “primogeniture” [Erstgeburtsrecht in German, lit. First-Born-Right, which is probably what we’d call it in English if not for old 1066]. Primogeniture mandated that the oldest son received all the land when the father died. Moral and other questions aside, — What impact does primogeniture, vs. shared-inheritance, have on fertility?

Commenter Rollory got me thinking about this, with remarks he made regarding the steady decline in French fertility after 1789, which quickly fell to the the lowest in Europe and stayed there. My idea was that “cultural pessimism” overtook the French after their chaotic revolution, ensuring low fertility. Rollory pointed out something more quantifiable (perhaps): Napoleon abolished France’s practice of primogeniture. Rollory speculates that the two events — France’s TFR slide and the end to primogeniture — were related.

The reasoning, briefly, is this:
— European parents are highly interested in their children’s success. In a society with an equal-inheritance policy, having multiple heirs would split the estate into meaninglessness. Every new child means the estate will split even more, perhaps thrusting descendants into the poor-house, even if the original father had an ample estate. Family would be started later for economic reasons, and so fertility would fall.

— On the other hand, wouldn’t extra children be even more of a dis-incentive in a Primogeniture system, as non-first-borns would inherit nothing at all!

— There is the matter of focusing on the parents’ decisions vs. on the children’s decisions, which can devolve into intractable Chicken-and-Egg-ism. E.g.: Although equal-inheritance may decrease parents’ desire to have more children, it would boost non-first-borns’ potential fertility, by giving them some starting capital. (Stever Sailer’s “affordable family foundation”). From there, in theory, the ablest would acquire more wealth, forming an ever-shifting aristocracy of merit, “Meritocracy”.

— There is the fact that all European states abolished this practice, but not all saw such a sharp fertility decline as did France. And industrialization changed the game, for sure. Rural land ownership had less and less to do with potential wealth earnings as the 1800s drove on. But France’s fertility slide came mostly in the 1790-1820 period, still mostly pre-Industrial.

— Finally: In the Malthusian past, high fertility was not necessarily a good thing. Primogeniture may have kept fertility lower than it could be, but maybe that was good! (This is a tangent; the question of whether it raises or depresses fertility is separate from whether high or low fertility is better!).

I don’t know which position is right. There are viable arguments both ways.

It seems that scholars have been just as puzzled and equivocal. Two such investigations into this question appear to have found opposite results:

1.) “Primogeniture and fertility: fertility models with unequal bequest” (1984 [link])

The general pattern of results suggests that primogeniture will reduce desired fertility, but possibly the major contribution of this presentation is that no simple relationship exists between primogeniture and fertility.

2.) “The coevolution of human fertility and wealth inheritance strategies.” (1998, [link])

The model is used to show that, in the unpredictable environment of a traditional pastoralist society, high fertility and a biasing of wealth inheritance to a small number of children are frequently optimal. [Optimal = having highest number of surviving grandchildren].

These two results appear to conflict with each other.

The latter study may not be relevant, as it deals with “African pastoralists”, not Europeans. Everyone knows Africans and Europeans have opposite breeding strategies.

One thing is for sure, I suppose: In primogeniture, the eldest son’s potential fertility will clearly be higher than otherwise, while his inheritance-less brothers will have lower fertility. The pro-Primogeniture position would be something like that old slogan “Capitalism is the unequal distribution of wealth, Communism is the equal distribution of poverty.”

Finally, a paper called “Primogeniture, Monogamy and Reproductive Success in a Stratified Society“, 1994 [link]

The author looks at this very question, as applied a to a European-esque aristocratic society.

In an environment where there are strong increasing returns to wealth–particularly in a society where the accumulation and retention of wealth depends on military strength or on influence in the political and legal system–there can be a genetic advantage to endowing a single son with a very large inheritance rather than dividing inheritance in an equalitarian way among one’s offspring. Because of his great wealth and influence, a single heir is able to sire an extremely large number of children by many women. In contrast, even a wealthy female is biologically constrained to bear only a relatively small number of children. The way in which a female can achieve the greatest genetic representation in future generations is to be mother of a line of future male heirs. Parents of female offspring who wished to maximize their reproductive value would therefore be willing to pay a large amount to have their daughter married to an heir of a great estate. This willingness to pay should be translated into large dowries. These facts seem to be consistent with what is known about ancient civilizations and about early modern Britain.

[However,] the hypothesis of reproductive value maximization does not receive unambiguous support from the tests made here.

I suppose the take-away message from that is: Primogeniture raises fertility for the single-heir in certain social orders. Such as feudalism.

But a social model that reaps these benefits would have to be dejure or defacto polygamous! Dejure polygamy has typically not been a European tradition. (See here).

Primogeniture would tend to reinforce aristocracy, and as such has the potential breathe life into even the stalest of feudalisms.

Can an advocate of Primogeniture offer a better defense of the institution than I have? (I admit I lean against it, but I am open to being all rational arguments).

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3 Responses to Primogeniture and Fertility

  1. Statsaholic says:

    I think a major advantage of primogeniture is that it allows a division of labor among siblings.

    The eldest son can concentrate more on cultivating the conservative virtues, while the younger sons can concentrate more on taking risks and being adventurous.

    Getting rid of Primogeniture deprives society of first born heirs, those men who have so often been the pillars of society, men who feel the weight of a familial tradition that they must try their best to live up to.

    Also it deprives society of younger sons who go through life taking more risks, feeling a greater need to prove themselves and achieve success.

    Just look at how America is losing in Iraq and Afghanistan. A lot of it may be due to the fact that shared-inheritance makes all sons equal, and therefore equally irreplaceable.

    It also feels to me that shared-inheritance would help promote an ethos of parents having fewer children.

    The basic issue is that estate owners don’t get punished for having more children under primogeniture.

    In contrast, under shared-inheritance it really does hurt you to have more children.

    It’s better to have two non-heir sons than one non-heir son. After all, with two non-heir sons it’s more likely that one of them will make his way in the world without the aid of an inheritance.

    But having another son under shared-inheritance has the effect of making your previous sons less valuable, a situation which doesn’t obtain under primogeniture.

  2. Statsaholic says:

    But a social model that reaps these benefits would have to be dejure or defacto polygamous!

    In many times and places wealthy men have had de facto higher fertility than less wealthy men largely due to having lower mortality among their children, as opposed to it just being a question of the wealthy men reproducing with multiple women.

    Also there’s the issue that often a wealthier man can marry a younger woman with more fertile years ahead of her.

    If a wealthy man has his first wife die, which was quite common in the days before modern medicine, he could have an easier time attracting a second wife.

    This would increase the fertility of the wealthy man without the situation really involving polygamy.

  3. Rollory says:

    “wouldn’t extra children be even more of a dis-incentive in a Primogeniture system, as non-first-borns would inherit nothing at all!”

    Once you decide that you want more than one child, this disincentive isn’t really a factor, as all subsequent children will face the exact same situation. It’s a barrier that has to be crossed, but once crossed, it never gets worse – and the additional labor from having the extra hands around the house can make up for it (kids worked dawn to dusk too). In an environment where the estate is evenly divided, however, you have to reconsider the choice with every single additional child, and it’s worse each time.

    To the general thrust of the post (and with the caveat that this is entirely hypothetical, I have no actual evidence on the subject): primogeniture means that the estate remains intact and subsequent children have to go elsewhere. Maybe they go to the city and find or make a niche there. Maybe they work as field hands for a neighbor for a while. Maybe they work out a deal with someone who owns some land but hasn’t been able to work it, where they clear it and work it for them for a time, saving enough to be able to start their own household. It encourages settlement moving outward, the clearing of new land, the development of new businesses – in short, wealth creation, as opposed to wealth divison and redistribution. Which is exactly what would be needed to support an expanding population as opposed to a stagnant one. Sure, all the second and third and later sons are starting from nothing, but wasn’t the entire continent of North America settled that way?

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