41 Comments

Don’t fall for this nonsense, Arnold. There is zero empirical backing for any of these ideas. Childhood diseases, smoking, work accidents, wars, death in childbirth, death by exposure - the causes of death before our generation were not weeding out bad mutations, they killed more or less indiscriminately. Rh+ children of Rh- mothers (like my children also) are not carrying mutations that are bad for human fitness, any more than anyone else. The psychological distress our society is facing now is not genetic, it’s traceable to all kinds of causes, as Haidt and others are pointing out, not least of all due to our secular age of meaninglessness, which was not caused by mutations. Low birth rates are not caused by some physiological mutation detection system that tells people not to have children. The ideas in the Toby quotes are all just such nonsense - surely the byproduct of his excess mutation load.

Expand full comment

That's a bit dismissive, Stephen. You seem to be saying there are no bad mutations--yet we all carry them; whether they are fatal or not depends on the environment.

Infectious diseases are not indiscriminate; survivors differ genetically from the dead. E.g., the impact of the Black Death on survivors--acne (hyperinflammatory response to gram-negative bacteria) seems to have been selected for. Polymorphic diseases (e.g., sickle cell, thalassemia) are caused by genes that were advantageous in a high-malaria environment, but deleterious in the absence of malaria.

The dramatic reduction in infectious disease deaths over the past century has likely led (among other factors) to the explosion of autoimmune disease in the past decades.

Self-selective breeding has probably contributed (along with diagnostic shift) to the rise of autism & ADHD.

Expand full comment

1) There are non-lethal bad mutations.

2) The rate of mutation accumulation has increased as mortality rates have gone down in the West.

3) This excess mutation load can impact intellectual / psychological traits.

4) The effect size of 3) is high enough that it can noticeably change populations over the space of ~200 years.

5) Our society has been noticeably changed by excess mutation load over this time period.

6) Our society has been negatively impacted by excess mutation load among [insert target population] causing [insert negative trait].

This series of statements goes from obviously true science, to plausible hypotheses, to making stuff up (pseudoscience), to irresponsibly lobbing idea bombs into the public discourse. The idea bombs cited by Arnold here are fairly mild, but this same style of analysis can be (and is) used to lob nasty and highly explosive idea bombs. The type of pseudoscientific analysis employed by Tooby makes me very uncomfortable.

Expand full comment

Do you have an opinion on W.D. Hamilton's Planet Hospital hypothesis?

Expand full comment

No. I haven’t heard of this. Do you have a link?

Expand full comment

Sorry about the delay as I don't monitor this site often.

Expand full comment

The problem with the mutation argument is that most significant mutations just cause spontaneous abortion. If the child makes it to term, they probably do not have many serious mutations. Mutations are not the same thing as traits, and whether traits are good or bad tends to be a subjective determination. In chickens, good laying traits are not the same as good meat traits. So too with many human traits.

Expand full comment
Apr 8Liked by Arnold Kling

I know quite a few high IQ people who are very religious today, and have a high fertility rate. It’s not IQ that leads to skepticism about religion, but a range of other factors, including the massive change in social organization and the presence of so much scientific knowledge, which means that the old “god of the gaps” approach is no longer effective.

I’m curious, though, about the idea that it is some genetic factor rather than the usual suggestions - lower infant mortality, reduced poverty, higher women’s education, and lower religious attachment which explain lowered birth rates.

Expand full comment

I'm not going to suggest I'm certain there is no such genetic factor but until I hear something more like real evidence rather than correlation, I will remain skeptical. Maybe bad mutations have something to do with difficulty conceiving but I see no reason to think bad mutations cause people not to want kids.

Expand full comment

I have a Masters in comparative genomics and I’m working (slowly) on the PhD. Tooby’s story is crap. I would probably assign the task of explaining what’s wrong with it to some of my Junior students.

He doesn’t really seem to understand what a mutation is (point mutations are just the tip of the iceberg) and how good living systems can be at surviving in spite of them. If every non-advantageous mutation had to be weeded out, as he seems to think, nothing would be able to live for more than a generation or two.

Some pointers:

The field that tells you how a given (simple) mutation plays out in an organism’s evolutionary trajectory is called evolutionary dynamics. It’s sophomore level. Tooby doesn’t know anything about it.

The field that explains how proteins can retain function despite changes in their structure due to changes in their coding gene(s) is biochemistry. Junior level. Tooby doesn’t understand it.

The field that explains how mutations to regulatory regions can be highly advantageous is systems biology. Senior level. I wonder whether Tooby knows what a regulatory region is.

And the field that encompasses what Tooby is trying to do in his analysis, where you consider some kind of shock to a population and predict how its genetic composition will change, is population genetics. It’s highly mathematical and is considered one of the hardest sub fields of biology. Unless he is very unusual, as an anthropologist Tooby is way out of his depth here.

Expand full comment

Yes, there is more load per generation. No, this has nothing to do with lower birth rates.

Expand full comment
Apr 8Liked by Arnold Kling

I try to read all of John Tooby's Edge essays at least once a year. : )

https://www.edge.org/memberbio/john_tooby

Expand full comment

After reading the bits Arnold shared of this one, I'm not at all inclined to read more of Tooby but maybe you can convince me to reconsider

Expand full comment

"Perhaps the people who are having families have fewer harmful mutations"

They are. Purifying selection is still operating. Here are two papers on this, the first using genomic analysis from the UK Biobank (https://www.biorxiv.org/content/10.1101/2020.05.26.116111v3.full) and the second analyzing the effects of paternal age (the primary determinant of average de novo mutations) on fitness in four different populations (finding modern Sweden to be comparable to colonial Quebec: https://royalsocietypublishing.org/doi/full/10.1098/rspb.2017.1562). However, your hopeful conclusion does not follow, because there is directional selection (which is not the same as relaxed selection) for bad traits (low IQ, ADHD, coronary artery disease, obesity, criminality and so on) (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9463317/).

Expand full comment

My family doesn't, nor does my wife's family, have medical miracle children. I would not claim that medical miracle children or mutational loads are non factors. However, we do both have grandmother's who had multiple teenage pregnancies before their careers. Even my grandmother in law that didn't have teen pregnancies had three children first before going back to school to become a teacher at 40, and then having a 20 year career. My wife in contrast didn't have any children before having nearly completed graduate school and being 30. And of all the relatives there is not a single teenage pregnancy and maybe 2 births at all before the age of 25. There is a conceptualized shorthand in my head that I like to call Baumol's cost of status disease. I don't think that actually makes any sense, but I think of it as the ever rising educational cost of status and its intersection with the fertility window. 35 is defined medically as advanced maternal age. In addition if you take Alex Nowrasteh's opportunity costs, which actually goes hand in hand with Alex Tabarrok speaking about Linder's theorem and its intersection with the limits of the fertility window I think you get most of the way there. I mean couple this with most people being intertemporally irrational in the way that you have talked about previously with regard to the goal of becoming a grandparent and if you told people this no one would listen when young. Not sure this summation and personal anecdotes is actually contributing any new information. Tabarrok: https://marginalrevolution.com/marginalrevolution/2023/06/the-harried-leisure-class.html

Expand full comment

Baumol’s cost of status

Is a good phrase for thinking about the different realities of economic production and status.

Econ production in a market is win-win positive sum. All can increase. Status production is a relative ranking of win-lose. For everyone who goes up in rank, like Top Tennis Player, another has to go down.

Expand full comment

Two things. 1)A living faith and knowledge of the Bible while working to live by its precepts brings about a robust mind and psyche; I am a personal witness to hundreds of lives; hearts and minds; becoming healthy through this process; and 2) There are overwhelming negative vs helpful genetic mutations in every offspring of all carbon based lifeforms. The obvious result will be extinction of every species. Brings to mind two realities: We are in the process of becoming extinct; (and for those who still believe in the THEORY of Evolution, the science proves it is utter nonsense); and that the only meaningful thing we can do on earth is to have faith in Christ and reverence for God. The "sickness" we see everywhere, physical and spiritual; is a sickness brought about by humanistic nihilism.

Expand full comment

There is almost no such thing as an absolutely negative mutation. A negative mutation depends on the circumstances of the world. What is beneficial in one world is harmful in another.

What is clear is that a high IQ is an evolutionary disaster nowadays because it makes it hard for someone to believe in traditional religions, and traditional religions are what cause people to have offspring today. Is this a terrible and dreadful thing? I'm not sure. A gene that causes its bearer to be a left-wing atheist woke person is not something we hope evolution will preserve.

Expand full comment

Fascinating article and an interesting hypothesis. Thanks.

Expand full comment

Absent new technology, eugenics = dead children. Always has.

When you ask how NW Europeans got so smart, it was the dumbs not saving enough for winter and their kids starving to death.

"Perhaps the people who are having families have fewer harmful mutations, so that dysgenics will reverse in future generations. But perhaps not."

Those Koreans, what shitty genetics.

I think we are selecting for people who breed without thinking, and this is correlated with not thinking much at all. In past child mortality would have taken care of that.

Expand full comment

Isn't the concept of dysgenic just environmentally contingent. Are blind cave fish dysgenic. This whole discourse acts like evolution is some process of improvement rather than just a process of gene survival. What is some traits just don't matter that much anymore and others matter more - are those still "good" traits? Some of this seems like communism - the idea that groups as though they are a living organism are more important than individuals.

Expand full comment

It seems pretty likely to me that the main cause of birth dearth is the combination of raised living standards derived from non-child labor and effective birth control. Many people will not have children if they don’t need them.

Expand full comment

"A few of these are in some sense “better” ... most are bound to be worse. Similarly fragile profiles would not have been found in people 200 years ago, ...Modernity has intervened against the evolutionary process."

Caesarian sections for giving birth are a huge example of bigger heads, & likely smarter, who survive and have their mothers survive. My daughter-in-law just had her second C-sec for her second child.

The high IQs of Ashkenazi Jews is almost certainly related to cultural pressure to marry smart, influencing the genes that are reproduced. Culture has dominated Darwinian disease selection for a few thousand years--since agriculture (to support beer making?). But Black Death survivors have different genes, somewhat, than those who died without issue.

The near-genocide of Native Americans due to small pox & other white diseases was a huge example of gene non-survival when meeting an epidemic. Their bad tolerance for alcohol is also a cultural-genetic mis-match.

Worse is the current govt programs that hugely support bad behavior, dominating the genetic tendency for "the prevalence and severity of psychological fragility would tend to increase." When the govt rewards carelessness & irresponsibility, including taking out college loans that aren't repaid as well as having kids that aren't taken care of by their bio-fathers (sperm donors), such bad behavior becomes more prevalent.

The birth dearth, like in S. Korea, has almost noting to do with genes changing, even for the better (like more height there than N. Koreans, maybe 2-3 inches now). It's primarily cultural.

And our civilized society needs to support couples getting married, and kids from married couples--Even Tho such kids and marriages have less "need" than kids of unmarried mothers.

It seems more likely that further support for married couples who have a child to get INCREASING support for additional children is more likely to improve the TFR faster, than trying to induce more women to have kids before they want them. Whatever the genes are for a couple to marry younger and have kids, those genes will be reproducing more than the over-educated childless women who have been career driven high achieving, now lonely 40+ writers like a Ginerva Davis whose genes will join the many failed natural experiments.

Maybe the only high IQ women to reproduce in the current and near future generations have genes for more child raising pleasure than career/ wage-slave achievement. Which is more like what more high-achieving men have--but most have a wife at home to help with the family. Or more than one wife, tho serially (mostly) monogamous one-at-a-time in the OECD Christian oriented countries.

Expand full comment

"The human condition used to weed out harmful mutations. But modernity has shifted the balance."

I agree this is an accurate summary of what Tooby writes but I find it utterly absurd. Modernity has made many mutations which were once harmful less so or entirely not harmful. Unless one fears antibiotic resistant pathogens will eventually take more than ever, the mutations that modernity allows are ones no longer harmful.

Expand full comment

Add a lot of salt to the statements of Tooby on evolution. Noticed the lack of math in his analysis. Just hand waving is no to be believed. A good example of the Dunning Kruger effect.

Real analysis in this area gets into math real quick. Also a big hunk of selection comes before and during fertilization itself where gene pairs that don't work fail and the cell dies.

Having raised many different species at well over 50 generations with similar situations of removing young mortality, I saw no decreases in fecundity data. We are talking only a few generations since we knew enough to decrease childhood mortality (only modern medicine actually worked and all the "great leaders", "Gods", and prayers failed). If he as anywhere close to being correct, the Arabs would be an even larger genetic mess from inbreeding than they area (significant but minor impacts and not impacting population growth rates).

Expand full comment