Lyman Stone on the fertility decline

people are having fewer children because they want fewer children

Lyman Stone writes,¹

1. Good economic growth is connected with higher, not lower fertility

2. Higher child mortality is associated with higher fertility

3. Higher fertility preferences are associated with higher fertility

4. Life expectancy, population density, and irreligion don’t seem like persuasive candidates for low fertility

Pointer to his substack from Tyler Cowen. As I write this, the link for the post looks funky.

Stone has a chart that shows a decline in desired family size along with a decline in fertility. The chart summarizes these variables for the world as a whole.

Both actual and desired fertility have fallen since 1960, but actual fertility has fallen much more. The biggest reason for this is actual fertility is also influenced by child mortality, which has fallen a lot since 1960.

To clarify the last point: when child mortality falls, it takes fewer babies to reach your target family size, so fertility also falls.

The chart shows that the worldwide average of desired family size has fallen by about 1 child, from four to three. Stone insists that this is primarily a cultural phenomenon. other variables either go the wrong way (he argues that income is positively correlated with family size) or have small effects. Concerning culture, he writes,

perhaps the most common human desire is simply to feel good in comparison to other people you see as peers. …the most powerful part of your usual, normal-circumstances brain circuitry is the interpersonal comparison function. …What people want is not to maximize status, but to avoid the very high psychological, social, and material cost of being made to feel inferior, subordinate, or part of the out-group.

Stone’s emphasis on culture serves to explain why fertility has fallen in many “underdeveloped” countries.

Fertility behaviors change if and when Western CULTURE arrives, which is sometimes before and sometimes after when societies actually experience economic growth, if they ever do.

In his view, the apparent material link between economic development and lower desired family size is an optical illusion. The driving factor is other countries’ cultural closeness to the West. The apparent role of economic development comes from the fact that there tends to be a correlation between development and cultural closeness to us. But cultural closeness is the dominant explanatory variable.

Stone makes this claim:

it was much easier to adopt some pieces of Western culture (like small family size) than others (like inclusive political institutions, independent police forces, rule of law, democracy, or property rights).

I do not see why it should be “much easier” to transplant cultural values to an entire population than to adopt specific institutions. Mark me down as a skeptic on this part of his argument.

But he thinks that survey data back him up.

People in poor countries earnestly think, have genuinely been so massively deceived by Western success, that if they just arrange their sex lives like Europeans do, they’ll get rich, even though this just isn’t at all true.

Actual family size vs. desired family size

Taking the decline in desired family size into account, another important driver of lower fertility has been a decline in actual family size relative to desired family size. Stone argues that the culprit is a lower marriage rate.

It turns out in most countries, fertility falling below desires is overwhelmingly driven by nonmarriage or delayed marriage. In Turkey, fertility is falling when and where marriage is falling. And this is true basically everywhere. In fact, it’s so true, I wrote a long paper a few years ago all about how marriage today remains an essential determinant of fertility, called “Marriage Still Matters.”

Developmental Idealism

What I least like about Stone’s essay was the phrase “developmental idealism,” which means the belief that the way for a country to get rich is to have smaller families. He places this at the center of the cultural values reducing fertility.

Again, mark me down as a skeptic. I have a hard time believing that people are inclined to base their personal decisions on this vague cultural value. Obviously, China could enforce this, but that is an exception.

Stone points out that more education tends to lead to lower fertility. But then he dismisses education as a causal factor, because people educated in madrassas tend to have high fertility. But I am willing to just treat madrassa education as an exception and still view education as the main driver.

In the United States, I blame our attitudes related to education for the decline and delay of marriage. Some of that is the ideology of our education sector, which tends to be anti-natalist and anti-marriage. Some of it is the widespread view that you have to “complete” your education before you can get married and have children, with “complete” requiring ever-longer pursuit of degrees.

I do not think that we need “developmental idealism” as a separate explanatory variable. I say just look at the cultural treatment of education, here and around the world.

1. Stone’s essay could fall under “statistical methods links,” “fertility links,” “psychology links,” “social learning links,” or “economics links.” I decided to give it its own post.