IQ Shredders vs IQ Incubators

Singapore vs Mea’Shearim

‘IQ shredder’ is a concept coined by Spandrell in a post about Singapore, but which applies more generally to cities that attract high-IQ migrants with economic opportunities and high standards of living. Such global talent hubs, however, tend to have some of the lowest fertility rates, functioning as IQ shredders that hamper the long-run future of the positively selected gene pools they attract. In these cities, human capital can be efficiently cashed out in economic output, but only by significantly diminishing its ability to persist into the future.

But if Singapore is the IQ shredder, where can one find an IQ incubator - something that trades economic output to preserve genetic potential? One candidate surely has to be Mea Shearim in Jerusalem. Mea Shearim is a time capsule, preserving 18th-century shtetl lifestyle, and as good an example as any of Haredi insularity. Mea Shearim is nothing like Singapore. For one, few outsiders are trying to move into Mea Shearim.

But Mea Shearim is probably not a human capital wasteland. Though the Haredim are not known for their economic or scientific contributions, it’s not for lack of cognitive potential. In 2022 PISA exams, “ultra-Orthodox girls scored 474 in mathematics, compared to 473 for secular girls, 454 for religious girls, and 388 for Arab-speaking girls. In reading, ultra-Orthodox girls opened a 12-point gap compared to state-educated girls, and in science they scored 9 points higher than national -religious girls.”

For context, Haredi girls' schools teach roughly 75% of the state core curriculum, have thin oversight, and don't sit the bagrut (standardized tests). The average household income of the Haredim significantly trails that of the broader populace (even after accounting for welfare, etc.). Environmental factors alone would have you predict precisely the opposite result. I suspect these girls—who blew their normie peers out of the water—will likely have a smart kid or six, which is roughly the TFR of the ultra-orthodox in Israel. The Haredim, then, appear to be reproducing a population with considerable cognitive potential, despite and perhaps because Haredi culture itself is inimical to economic productivity.

Intelligence is highly valued in the Haredi world, insofar as verbal intelligence is correlated with excellence in biblical scholarship. Like elite universities, the yeshiva world has a prestige hierarchy, with competitive admissions sorting promising students into institutions that reflect the scholarly caliber of their students and alumni. A boy who studies at a prestigious yeshiva gains status in the marriage market.

I briefly looked into whether this status advantage translates into a reproductive advantage (in relative fecundity) beyond priority in mate selection. This study by Gabriel Gordon tracked the trajectory of 115,696 men who attended Haredi secondary yeshivas and found that men who stay in yeshivas past 40 have almost twice the number of offspring as those who never entered post-secondary kollel. For this to be evidence of positive selection for intelligence, we'd have to assume that men who remain in religious study longer are positively selected for intelligence themselves (I suspect this is true but haven't validated it.)

The Haredi world thus has a status hierarchy that rewards intelligence and may even confer a reproductive advantage on those who possess it. But more importantly, even if the community isn’t positively selecting for intelligence at the current margin, what it does incredibly effectively is encourage and preserve high-fertility norms. The fertility gradient across Israeli society tracks religiosity, with the Haredim on one end and secular Israelis on the other, with a TFR that’s just below replacement. Religiosity in turn tracks the strength of fertility norms. Over half of Haredi women in Israel marry before their 21st birthdays. The community is strategically Luddite about reproductive tech, maintaining strong sanctions against birth control while being somewhat tolerant of fertility-enhancing technologies like IVF.

Now consider the relationship between IQ and fertility in the modern globalized world. IQ is a useful currency for acquiring status both via material wealth and via paths that involve knowledge production or other creative pursuits. The Singapore example evokes images of a high-stress rat race. But the modern world offers ways to convert IQ into status via paths that aren’t nearly as stressful (e.g. academia). However, the Steven Pinkers and Terence Taos of the world aren't busy repopulating the earth in their free time. Why?

Because status markers for global cosmopolitans are largely disembedded from cultures that have been shaped by evolution. It’s not so much that the global monoculture means everyone is necessarily competing in the same status hierarchies. You could be an Effective Altruist, for example, in which case you care about approval from other Effective Altruists and not about maximizing wealth. But Effective Altruism has grown by persuading new people to become effective altruists, not by having its existing members produce and raise the next generation of effective altruists. As a result, it is not adept at inducing high fertility in its members.

Both worlds reward intelligence, but in the Haredi world, status is embedded in a culture that also demands reproduction. A smart Torah scholar who chooses to stop at kid no. 1 will probably face social sanction, however prestigious his yeshiva credentials. In the modern secular world, on the other hand, intellectual achievement can confer status without any corresponding expectation of reproduction.

The global monoculture is not a single culture per se, but a social environment in which individuals can participate in any number of status hierarchies without belonging to a culture that needs to reproduce itself. It is what remains after the dissolution of traditional cultures, most of which put up half a fight against modernity and basically lost. Haredi Judaism, however, is itself an adaptation to modernity. The Jewish Enlightenment in Europe provoked something of an immune response, and these traditionalist communities reinforced their boundaries and developed institutions to resist assimilation into the wider society.

Maintaining a radically different social equilibrium from the global monoculture necessitates both insularity and exit costs. From the perspective of the Haredim, the outside world is not a different culture with equally strong but different norms. The outside world is simply an activation of individual choice over social norms. Cultural osmosis must thus be forcefully restrained, while also making it costly for individuals to opt out of the community.

In the ultra-Orthodox world, where marriages are arranged through families and matchmakers, siblings of deserters can have their marital prospects harmed as a result. Similarly, this channel can be used to punish things like smartphone use, which is itself a risk factor for cultural osmosis from the outside. Insularity is a powerful weapon because insularity itself makes insularity easier to enforce. The more insular the community already is, the cheaper it becomes to punish defection by imposing social costs that can’t easily be borne by someone with little social capital or cultural cache outside the community.

This incubator in Israel, however, is sustained by a tax base and protected by a military to which it contributes relatively little. The incubator is, in a sense, free-riding on the shredder. But equally, the shredder needs human capital to shred, some of which has to come from attrition out of the incubator. Currently, the attrition rate is a rounding error (10–15% per generation) relative to the difference in fertility between a population that’s barely replacing itself and one that’s roughly tripling every generation. However, if you’re tempted to solve for a higher attrition rate, you risk breaking the incubator. And this is all assuming that solving for this is even remotely interesting to two radically different cultures that share little in the way of a common vision for the future.