Nov 10Liked by Robin Hanson

I think there is something in this. I grew up in a very wealthy NYC suburb, and having children in one’s 20s was just not done. When I moved to a southern city in my 20s, I was shocked at how many women my age had children and I couldn’t shake the feeling that what they were doing was somehow quite trashy - even though they were all middle class married women. It wasn’t until I was visiting my hometown and realized you seldom saw a woman under 35 with a small child that I realized I had absorbed the norm that “having a child in your 20s is for low class people”. Similarly, having more than two children (unless triplets) was also seen as rather déclassé...when I was pregnant with my 3rd, rather than congratulations I got some ribbing about “so, when will you be moving to a trailer park?”

I’m not sure if the 2-child or less thing is due to the enormous amounts of parental investment involved in raising an upper-middle-class child; or if it is a side effect of delaying motherhood to 35 or older with the associated fertility issues and need for expensive fertility treatments.

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How do you tease all this out from some more obvious facts, namely: the widespread availability of cheap and reliable contraception, thus decoupling the pleasure of sex from childbearing, and the extension of education and full human rights to women resulting in their full entrance into the commercial work force? For most of human history, and still for all of the rest mammalian history, producing offspring was the natural consequence of pursuing sexual desire. Now it is a conscious choice.

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Just an anecdotal note. I live in Finland and have been following The Ukrainan war a bit. Before the war a russian thintank called The izbrosky club,which is close to Kremlin, suggested that Russia should abandon western style of Capitalism because it would lead to destruction of country via collapsing population.

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Nov 10·edited Nov 11

Did the rich of yesteryear really have less kids than their underlings or did they just have more unacknowledged bastards, more postnatal abortions, etc as bastardry was mostly a class thing as the poor couldn't afford the lifestyle needed to support it. And even today, look at Musk or various other celebrity males; they def making babies left and right, Tyson had what, 7 kids? De Niro, 7? Jefferson with his slaves? Hell I'm middle class and I've had six with four women and those are only the ones I know about.

While I have no proof I think it's reasonable to assume access to sex, especially multiple fertile partners throughout decades, increases offspring generally pre effective birth control era and I've seen nothing to suggest the rich of yesteryear were less promiscuous than the poor, quite the opposite actually.

I think the problem you have now is more what happens when women can individually choose the nest size to maximize their portion of the maritial resources with no downside. In my life I've met maybe a half dozen men that didn't want to have MORE kids. Met plenty that wanted no kids but it seems to be "none or a lot". whereas most women I've met seem to be in the one to two category and often begrudgingly so after two as one and a spare is enough to lockdown lifetime income whereas three+ does nothing but reduce their handbag count.

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Also, I guess I don't understand why any explanation is needed. I mean let's just take the simple model where people have kids when benefits (including emotional and getting to fuck in absence of birth control) exceed costs. Now postulate that the emotional satisfaction of raising additional children falls off pretty quickly (it's not that much more satisfying to raise the 4th as it is to go from 1 to 2).

That predicts that in a world with effective birth control, high child survival rates and with both parents pursue careers (meaning that having more kids imposes costs in terms of career) there would be a strong pull towards few kids. Amplified if people tend to mimic peers.

But why wouldn't such desires have undergone strong negative selection effects? Well on this model anything short of generic change to directly desire more kids is fighting against the current and such a genetic change takes time under selection and until this most recent generation there has essentially always been one of those factors above to screen us from the effect x

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Nov 13·edited Nov 13

Selection neglect seems irrelevant to looking at ancestors vs parents of successful people

We don't usually see someone who had many children and a few grandkids got rich in the same light as someone who had 3/4 kids get rich

Part of this is probably that we care more about kids than grandkids, grandkids more than great-grandkids, and at about 7 generations we don't much care anymore

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Why do we need this theory, though? Higher income people have a higher opportunity cost in having kids and hence tend to have fewer. What more is needed for the general trend?

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This story seems to be structured very unlike the previous selection neglect examples for academics and businessmen. In both of those the imitators look at the very successful representatives of the class, and neglect that they aren't similar to an average successful representative.

In the fertility case, they are looking at the very successful "parent of rich/successful child"... but then they "should" be looking at parents of reasonably successful children, not at the entirely different "most great grandkids or later descendants" metric, no?

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I think part of it is the historically high social mobility that we have compared to previous eras. Unlike before, where there were smaller slices of people who had a chance at the big leagues and had fewer kids in order to go for it (say, merchants, bankers, lower nobility, etc.), we now have a large slab of people who can be convinced they have a chance to hit it big (nearly anybody with a degree or who works really hard). Therefore, they have to act like it - by delaying childbirth in order to get a lot of degrees, and work their butts off, and maximizing their lifetime net worth by investing everything now.

None of which you'd do if you thought "eh, I've got enough to live the way I do, and I could never make it in the big leagues".

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Maybe one way to test these status based evo-psych theories would be to compare people whose ancestors lived in small societies to people whose ancestors lived in large ones. Smaller societies, like hunter gather bands, would have had shallower status hierarchies, so probably a lower correlation between status and fitness.

East Asians have lived in large, settled , state pacified for probably longer than any other group and their fertility is also exceptionally low.

I can't find much on hg fertility but google says the Inuit fertility rate is 2.8, which doesn't seem that high.

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"So if people look at the more successful individuals around them, and ask what their relatively rich parents did to help make them successful, they will tend to see stories of parents who had fewer kids. "

But isn't giving your children more siblings not also an advantage? If you have a bunch of brothers and sisters, you may have to share parental capital investment, but you are surrounded by more people that (if things don't go too wrong) like you, trust you, help raise and socialize you and would be willing to cooperate economically with you.

So shouldn't we see large successful families that have high social status, which in turn would influence a couple's decision making on how to optimize the status of their offspring + themselves, as well?

Why do we tend not to see those stories instead?

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Why does there have to be a selection explanation? Why can’t it just be a random set of traits that weren’t selected against in the past, that are maladaptive in the modern context? Most humans are bad at reasoning about exponentials and probabilities, I don’t think we need to assume that “reasoning badly about exponentials and probabilities” was some kind of selected for trait in the past, just that it wasn’t particularly important during the vast majority of the human brain’s evolution. Similarly, I just don’t think “make sure to be motivated to have kids when there is a world of plenty, fun and meaningful things to do without kids, kids don’t provide much immediate return, and very effective birth control exists” was a problem human had to solve, so it didn’t.

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Robin, perhaps you don’t know Susan Blackmore theory on fertility reduction: her view was that in the past cultural transmission was communal and familiar, and consequently, familiaristic memes had massive advantage; in the current cultural environment, were ideas come to people by more heterogeneous sources, the cultural transmisión losses her familiaristic bias, and you get less children. As a general rule, the literature says that the most important variable determining fertility is female literacy.

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hi, strangely enough I also have a theory for the decline fertility involving prestige status, but it is more general: "56. Think of culture as a collective of evolving individual structures - in terms of Daimonion's (Daimonion, unpublished work) membionts - using people's brains as a substrate (if you not ready to go that far, just replace "membionts" with "self-replicating structures with differential stability in culture" in the rest of the article, and treat the brain not as a substrate in which membionts live, but simply as a node - a medium of storage and processing power for self-replicating and selected structure in culture).

57. The higher the total number of human brains and the more frequently they communicate, the higher the rate of reproduction, mutation, and specialization of the membionts. The more brains interact, the more complex the collective of membionts becomes.

58. Prestige status facilitates learning specifically through “info copying” (Henrich, Gil-White, 2001). Info copying is an anthropocentric view of self-replicating cultural structures - membionts . When learning by copying, “behavioral traits, the ideas, values, and opinions of prestigious individuals are also likely to be copied” (Henrich, Gil-White, 2001) because of the high costs associated with recognizing the key features. Prestige status thus dramatically helps membionts to reproduce faster in the symbiotic process between culture and humans.

59. Preferential attention to and learning from high-status individuals helped select for adaptive membionts in Homo sapiens' symbiosis with culture (Barkow, 2014) and kept the population of neutral or maladaptive membionts in culture at bay.

60. The greatest obstacle to the spread of culture is aggression and unwillingness to cooperate, for example, with out-group non-kin. Dominance status is rooted in aggression. This is why cultural evolution selects more and more for prestige status.

61. With the evolution of complex culture, the importance of prestige status grew. Prestige facilitates the spread of culture membionts. To replicate in the brains of the entire group of followers, the membionts need only access the brain of a prestigious person at the top of the local status hierarchy.

62. Today, prestige is a more important status acquisition strategy than dominance in Western human societies. US undergraduate women prefer prestigious men over dominant men as romantic partners, particularly in the context of long-term relationships (Snyder, Kirkpatrick, , & Barrett, 2008).

63. Open dominance is a low status signal in family or work environments in Western societies.

64. People are motivated by status to work for the culture, to replicate it, and to make it more complex.

65. But not all culture is adaptive to humans (Barkow, 1989).

66. Because of prestige status, many people in affluent societies invest much more resources in culture replication than in the past. They even go so far as to forgo their own reproduction in order to reproduce the symbiotic membionts. This explains the shocking decline in the reproduction of humans in affluent societies." (from a paper I write on the topic of money and prestige status)

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What if cultural evolution has accidentally selected for a family size and not an offspring number. Then as life expectancy shot up (and thus witnessing the early development of your great grandkids is now a thing) we have fewer kids. Or to say the same thing from the other side, if I’m in my early thirties thinking about having my second or third kid, but my grandparents are still around, my immediate family still seems big--even with one and two child households at each generation node.

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Would readers care to comment on Jose Yong's theory: When social status gets in the way of reproduction in modern settings: An evolutionary mismatch perspective


Ruth Mace (evolutionary anthropologist) was onto the idea that pursuit of status inhibited childrearing back in her 2008 Science article. Reproducing in Cities.


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