16 Comments

"Interestingly, levels of violence can also be higher when women are in a surplus (as compared to when the sex ratio is balanced or male-skewed). In these circumstances, men exploit the increased availability of mates, engage in sexual promiscuity and neglect their long-term parental investments."

The U.S. had a surplus of single women until the 1980s, partly because of a higher male mortality rate and partly because serial polygyny was limited by divorce laws. The same was true for other Western societies, particularly after the last two world wars (which killed off large numbers of young men). Yet that period had much lower levels of sexual promiscuity and higher levels of long-term paternal investment.

"a 2016 study by Ryan Schacht and colleagues found that rates of homicides and other violent crimes were higher in American counties where women outnumbered men."

You're not controlling for ethnicity. Those counties are predominantly African American. The African American population has a female surplus for two reasons: 1) the sex ratio is less male-skewed at birth, for reasons we don't fully understand; and 2) male mortality is higher, due to gang-related homicides.

Expand full comment

Ryan Schacht and colleagues controlled for % white, though not for % black.

–NC

Expand full comment

There is no White American community that has more single women than single men in the 20 to 39 year age bracket. None at all. Zero.

If you don't believe me, check out this interactive map: https://jonathansoma.com/singles/#2/5/2/0

Expand full comment

"The same was true for other Western societies, particularly after the last two world wars (which killed off large numbers of young men). Yet that period had much lower levels of sexual promiscuity and higher levels of long-term paternal investment."

It would be interesting to know if, of these males at war, those with fewer short alelles--which according to the study, are associated with increased risky behaviors--had a significantly higher survival rate.

This is something that would be nearly impossible to check, unless genetic samples were taken routinely, at enlistment time. This is unlikely to ever happen.

If indeed those males who survived the wars had fewer short alelles, this would genetically tend towards the lower levels of sexual promiscuity and higher levels of parental investment you noted--which, in sex ratios skewed toward greater percentages of females (as after a major war) is counter to expected anti-social behavior levels.

Expand full comment

One could examine ancient DNA from before 1914 and after 1918 to see whether WWI altered the frequency of alleles associated with promiscuity and low paternal investment.

Much has been written on this subject but little has been established. Did the Great War take a heavier toll on men who lived fast and were more willing to risk their lives? Or were such men less patriotic and less willing to die for a cause? Richard Lynn reviewed the evidence and concluded that it was inconclusive. http://doi.org/10.46469/mq.2019.60.1.4

Keep in mind that both world wars killed a lot fewer men from the U.S., yet, until the 1960s, paternal certainty was, if anything, higher among white Americans than among western Europeans.

Expand full comment

Thanks for the link.

I read only the brief abstract. I'd like to further consider what it means, especially in regard to these two diverging implications:

"Wars appear to have had a eugenic effect during the evolution of the hominids because those with greater intelligence, stronger moral character and better health generally killed and replaced those weaker in these respects."

The above statement leads me to think that *because* of greater intelligence, moral character, and better health, human groups that had these relative advantages replaced those without. These traits, taken together, conferred advantages in planning and execution, group cohesion, and individual physical prowess.

Since the statement is not clear whether the advantages listed applied mostly to the males of a group, and that all such males were involved it the conflict, I wonder if the abstract references only the men, maybe implying that the females also had these advantages.

But for sake of the discussion, I take it to mean all members of a discrete hominid group benefited. It could be otherwise, however.

Does this seem this way to you?

Then this.

"It has frequently been argued that this relationship has reversed in modern times because those with greater intelligence, stronger character and better health were disproportionately sent to fight in wars. In consequence, they were most likely to be killed."

This now shifts to the listed advantages, but as they affect only the combatants, and only in "modern times".

I think that the comparisons between how these traits affected the genetic profile of hominid groups as they evolved needs to be either on complete populations (male and female), *or* combatants (by far males) but not a vaguely identified amalgam.

Now I want to offer a personal observation that may/may not be valid.

I believe that in modern times, with the advent of compulsory conscription, it *tended* to include more intelligent male combatants than in previous times simply because formerly, when armies (combatant groups) were non-coerced, especially in wars of aggression, combat appealed more to the risk-takers (fast reproductive strategy) than to the slow reproductive strategy individuals.

If true, now that we no longer have conscription, we're back to the risk-takers being in greater abundance.

What do you think?

BTW, happy holidays!

Expand full comment

The more I study these questions, the more I become convinced that evolutionary change has been driven by long-term selection pressures, and not by one-off events.

Take Iceland. That country didn't have conscription in either world war (being officially neutral). Yet if we look at alleles associated with cognitive ability, we see the same decline during the 20th century that we see in English and Euro-American populations. https://www.anthro1.net/p/how-real-was-the-flynn-effect

Nonetheless, in almost any discussion on this topic, people will say: "Oh, it was because of the Great War! The best and brightest went over the top!" Well, Iceland's best and brightest didn't go over the top, and the same decline happened there.

The next ten years will see a revolution in historiography, as we chart changes over time in allele frequencies for various mental and behavioral traits. We will better understand why Western Europe took off while the Middle East stagnated, and we will better understand the connections between demography, history, and economics.

Expand full comment

I think a better explanation for why Europeans, Jews, and East Asians became the most intelligent races is because they historically died more from diseases, rather than famines and wars. I talk more about this here: https://zerocontradictions.net/civilization/r-k-selection-critique

Expand full comment

I am really enjoying this essay. There are, of course, aspects that I initially question or fail to see the effective mechanisms (e.g., disease linked to higher levels of intelligence--the causal aspects are nit entirely clear to me yet); I need to spend more time in these areas. But much of the content "clicks" with my observations and readings.

There is an aspect that I'd like additional pointers to. It is concerned with the idea that famine-adapted groups tend toward less intelligence simply because less brain activity conserves energy. This may well b truee, but perspective is needed.

Let's suppose that any individual has an averaged daily "energy budget" that they must live within over extended time. The total of all daily energy expenditure = 100%, and this consumption can come from basic autonomous physical metabolism (breathing, body temp control, etc.), conscious energy expenditure (running, working), and all non-autonomous mental activity (conscious thought, etc.).

For me to intuitively be comfortable with the idea that famine adaptation is *caused* by a need to conserve mental energy I'd need to know the *percentage* of non-autonomous mental activity of a given "average" individual in a disease resistance society as compared with a corresponding individual in a famine resistant society. I would then need to know the total energy budget in calories for each. You can see where I'm going with this, and why: how *great* a factor is mental energy conservation to survival in a famine-resistant society?

Do you know if any work has been done in this area, and if there are any available links?

Expand full comment

I'm glad that you like it. Regarding how famines may select for smaller brains and lower intelligence, I didn't intend to imply that that's the only reason why such populations tend to have lower intelligence. I edited the page to make this more clear and improve the readability.

Other factors that I mentioned were that: 2. wars tend to destroy civilizations, and famine-resistant populations are more likely to fight wars (for reasons explained in the webpage and here: https://thewaywardaxolotl.blogspot.com/2015/09/life-is-violent.html); 3. famine-resistant populations thus tend to have less complex civilizations and therefore less selectionary pressure for higher intelligence.

Unfortunately, I don't know the specifics regarding energy expenditures in humans, nor do I know of any specific studies. I am not an expert on that topic, but I see no reason to believe that famines wouldn't have a negative effect on intelligence, compared to populations where most deaths are caused by diseases.

I believe that this is a true fact because: 1. I have strong reasoning to support the claim, and 2. I can intuitively imagine with stochastic matrices and linear algebra that such genetic adaptations would eventually dominate such populations over time, even if the selection and calories saved are only marginal.

I've listed some other factors that likely influenced the natural selection for higher intelligence here: https://zerocontradictions.net/faqs/race#intelligence-tradeoffs

Expand full comment

All suggesting the different genetic groups would be better off in societies of their own. As was the normal pattern for a verylong time.

Expand full comment

"r-selected” (fast) to “K-selected” (slow). "What's r and K?

Expand full comment

He's referring to r/K selection theory: https://en.wikipedia.org/wiki/R/K_selection_theory

I think that r/K selection theory is basically false (https://zerocontradictions.net/pdfs/r-k-selection-theory-is-bogus.pdf), but Life History Theory (https://en.wikipedia.org/wiki/Life_history_theory) is mostly valid.

I also propose that there are better explanations for patterns seen in humans and other animals: https://zerocontradictions.net/civilization/r-k-selection-critique

Expand full comment

If you wanted to improve societies, e.g. eradicating terrorism, you'd want to support economic, social and other policies that reward K like behaviour and disadvantage r. It'd be interesting to know if the tandem repeat is associated with physical appearance or gracialisation.

Expand full comment