Kicking Away the Ladder?

A report from the Pew Center is the latest to document America’s rapidly declining religiosity. Pew’s numbers show a 12-point decrease in the percentage of Americans calling themselves Christians between 2009 and 2019, while those describing themselves as atheists, agnostics, or “nothing in particular” have risen from 17% to 26%.

These findings are mirrored in the General Social Survey, which has been asking respondents about their religious affiliation since 1972.

religious nones
Shaded area represents 95% confidence interval

The demographic surge of the religiously unaffiliated is a story of treatment effects triumphing over selection effects. A little context will help explain.

Natural selection seems to decidedly favor the religious. As the social psychologist Ara Norenzayan details in Big Gods (an excellent if at times slow book), religious societies, specifically those that follow omnipotent, moralizing “Big Gods,” have historically been able to outcompete others. To summarize Norenzayan’s findings, this is due to three factors, the first two of which are increased trust and greater social stability, both made possible by supernatural monitors (gods) that have allowed societies to scale by “building moral communities of strangers.”

In recent history, some societies (think Scandinavia and Japan) have been able to “kick away the ladder” of religion, replicating the monitoring effects of Big Gods through trusted civic institutions—police, courts, and others that allow for anonymous actors to cooperate in the same way religion used to. But there’s one other important advantage of religious societies that secular societies haven‘t been able to engineer: above-replacement fertility rates.

Fertility by Religion
I’ve restricted my search to 30 – 45-year-olds to try to account for the fact that older Americans are on average more religious and have more children. Huge confidence interval for Jewish women reflect low sample sizes.

The religiously unaffiliated reproduce at notably lower rates—so much so that, even as I’m writing a blog post about their astronomical demographic growth in America, the Pew Center projects they will decline as a share of the global population, from 16% to 13% between 2010 and 2050.

shrinking religiously unaffiliated.png

Followers of Big Gods, especially those of fundamentalist branches of religion, tend to have more children. Note: this is mirrored by the liberal-conservative fertility gap, and both are fueled in part by divergent views on reproduction.

To give you a sloppy illustration, consider the graph below, which I constructed using national-level data from 55 countries that appear in the 2012 Win-Gallup International Global Index of Religiosity and Atheism and Gapminder total fertility rate data from the same year. Nearly every country with an above-replacement fertility rate has a majority-religious population by quite a large margin.

more religion more babies
Horizontal line represents “replacement rate” of 2.1 children per woman. Vertical line represents median religious society in the data set.

In a personal email quoted by Norenzayan in Big Gods, a colleague confides that despite reviewing all available data and case studies back to early Greece and India, he was unable to find a single example of a secular society maintaining a birth rate higher than two children per women for even a century. France, Germany, Japan, and quite a few other countries are trying—and failing—to address this problem with a variety of subsidies. Thus far, there is no secular substitute for religion’s fertility premium.

So with forces of nature solidly in support of religion, why is it rapidly losing ground across the rich world? It turns out there are countervailing secularizing forces that, it feels safe to say, have grown powerful enough to chip away at the natural demographic advantage of the religious. Unlike the selection effects that propel religiosity, these are treatment effects, meaning they’re driven by exposure to certain conditions. In addition to the aforementioned creation of secular civic institutions, those conditions include education, rising incomes, and the general removal of existential threat (of the “where is my food coming from” variety, anyway).

Notably, somewhere around 78% of all “religious nones” are “converts,” if you will, meaning they were born into a religion and ceased to identify with it over time.

While there is some observable increase of religious unaffiliation within generations, the flight from religiosity is largely driven by generational replacement. In other words, it’s not like longtime worshipers have suddenly lost faith en masse—it’s that their grandchildren aren’t interested, and older generations are losing ground demographically. This fits the pattern of other paradigmatic shifts in public opinion, and to me, suggests there’s an element of timing involved, that conditional secularization may be contingent upon one’s formative environment.

The question that remains to be seen is whether or not the secularizing rich world can support itself. Our economies, infrastructure, and social welfare systems are reliant on people, and a large population that doesn’t reproduce will age with dramatic consequences (see Baby Boomers). In the long run, this is probably one of the most consequential political issues out there.

The Kids Are All Right: Follow-up

My post on the relationship between ideology and fertility rates generated some great feedback and critiques (albeit mostly on a Facebook thread). Sadly, none of this was related to the awesome pun in the title of the piece. (Seriously, no love for “The Kids Are All Right”?)

Well, life goes on.

In light of the interest in the subject, I’ve decided to do a quick follow-up piece to address some readers’ questions and adding a bit of information, particularly as relates to this graph from the original post:

Conservative have more kids

1. Are there more people on the political left?

A couple people asked about the ideological composition of the nation and the sample I used. This is an important question, because if the political right makes up a small enough minority of the population or sample, then my graph, which shows the average number of children per respondents of different ideologies but doesn’t convey sample sizes, is a bit misleading—or at least less compelling. So my fault for not going into it in the first place.

Per the most recent polling by Gallup, The American electorate identifies as roughly 26% liberal, 35% moderate, and 35% conservative. This is after two decades of a slow, steady increase in the percentage of Americans calling themselves “liberal.” More on that later.

The sample I pulled from the General Social Survey (GSS) reflects Gallup’s national numbers pretty well: out of the total 8,539 respondents sampled, 2,346 (27.47%) identified as some degree of liberal, 3,285 (38.47%) as moderate, and 2,908 (34.50%) as some degree of conservative.

sample distribution

2. Are there more women on the political left?

I believe this question is getting at the same idea: if the majority of women are left of moderate, then the higher fertility of women on the right is less consequential for the electorate. According to Gallup’s national numbers, 30% of women identify as liberals—the same percentage as call themselves conservatives. For men, those numbers are notably different: 40% and 21%, respectively.

The sample I used showed more gender parity in ideologies, but it’s not hugely off. At any rate, the important thing is that the elevated fertility rates of conservative women can’t be written off as the effect of a small sample size.

men and women political ideologies

3. But the population has been getting more liberal. Doesn’t that kind of throw a wrench in this narrative?

Only time will tell, I suppose! To be clear, this is how many people read the tea leaves, and the story I’m telling is a bit of heterodoxy. While I can’t offer a firm answer to this question now, I have a few remarks:

  • The past is no guarantee of the future. (Ask GE shareholders, amirite?) Just because the electorate has been getting more liberal doesn’t mean it will continue to.
  • I suspect the secular trend toward liberalization is as influenced by macroeconomics and sociological factors as it is individual characteristics and experiences. The question is, what will be the effects of today’s macroeconomic and sociological upheaval on future voters—or their children?
  • Relatedly, I think time horizon matters a great deal when evaluating whether or not the future looks liberal or conservative. This is theory on my part, but maybe populations naturally move to the right over the long term (because conservatives reproduce more) unless cultural forces pulling leftward—economic globalization?—are sufficiently strong and sustained.
  • Finally, I think it’s worth noting that America’s liberal ranks are mostly swelling at the expense of its moderate contingent, perhaps due to increasing political polarization.

americans becoming more liberal
America has been getting more liberal at the expense of its moderate contingent


There were a few questions brought up to which I don’t have good answers at the moment. Without promising when, if at all, to address them—I’ve learned not to make firm commitments relating to this fine blog—here are two excellent threads I should follow:

  • Does completing various life milestones (having children, buying a house, getting married) make people more conservative? There must be some longitudinal studies on this somewhere…
  • To what extent do children’s political views match their parents’, and is there symmetry between liberals and conservatives in this regard? (I linked to one study by Gallup in the last post that suggested a 70% match between parents and their children, but there’s probably a lot more work on this out there.)

The Kids Are All Right

A notion that’s become somewhat common among the left in recent years is that American conservatives are demographically doomed. Very often, this is discussed in terms of race and age—an allusion to the declining share of the non-Hispanic white American population and the accompanying erosion of its political sway, as well as the fact that conservatives tend to be older.

On its face, this seems like a tidy theory. But under the surface, I think it’s a great deal more complicated than the (sometimes wishful) theorizing of liberal pundits allows.

First, as I wrote a couple of weeks ago, the American concept of race, whiteness in particular, is a moving target. I think there’s a solid chance it will look quite a bit different in a couple of decades. But a more interesting foil, I think, to the liberals-own-tomorrow theory manifests itself in fertility rates.

People are having fewer children the rich world over, causing consternation among governments of countries whose economic futures depend on population growth. The political implications of this alone are fascinating, but the general trend obscures another interesting story: the intranational ideological disparity in fertility.

Liberals, it appears, are having fewer children than their conservative counterparts. Combing through General Social Survey (GSS) results from the last 10 years provides a clear view of this phenomenon. Among heterosexual men between the ages of 35 and 50, those who identify as “extremely liberal” had on average 1.79 children, whereas those describing themselves as “extremely conservative” had 2.43. For women, the difference was even starker: “extremely liberal” women had 1.69 on average to “extremely conservative” women’s 2.63.

Conservative have more kids

Many factors contribute to this disparity—most of which concern liberal women’s increased preferences for family planning. Anecdotally, liberals are later to marry, more likely to pursue advanced degrees, less religious, and, among women, more likely to pursue careers—the confluence of which makes for fewer babies. This trend seems to have gotten stronger over the past few decades.

Widening Child Gap
Note: Data for this graph are inclusive of all respondents 18 and older, meaning there’s probably some bias toward conservatives having more children, as they tend to be older. It’s also possible that causality flows both ways: having families might make people more conservative.

All this is significant because there’s at least some evidence that, most of the time, children end up inheriting their parents’ political views. This makes sense whether you view political ideology as a product of nature—differences in brain structure that give some a proclivity for novelty and others an aversion to risk—or nurture. Either way, if liberals are bearing and raising fewer children, it could mean fewer liberal adults down the line.

There are a few signs this might already be happening. One study found that after decades of decline, high school students’ support for traditional gender roles in the family has been rising steadily since 1994. Goldman Sachs pegs the ascendant Generation Z as especially fiscally conservative. Finally, a survey by the Hispanic Heritage Foundation of 50,000 14 – 18-year-olds found—shockingly, in my view—that the majority identified as Republicans and would support Donald Trump in the 2016 election. (An important caveat to this survey was that nearly a third of those polled would have declined to vote, had they been able.)

The policy preferences of an increasingly conservative nation are one thing—and obviously ideology colors one’s assessment of how good or bad that would be. But what really worries me is the thought of an even more politically segmented society; one in which an increasingly liberal minority of elites maintains control of the nation’s cultural power centers and an increasingly conservative majority grows frustrated with its obsolescence in the new economy, which, intentionally or not, places a premium on educational attainment, city-living, and delayed entry into family life.

Whether it comes to pass or not, we shall see.