Heredity, IQ, and Efficient Culture
Fun Stuff
My day job is coaching. If a high level athlete comes to me looking to improve, the first step is often to target her weaknesses. It’s relatively easy to double your bench press as a new lifter. It’s impossible as a master.
But this line of thinking can go too far. Steph Curry is the all-time greatest shooter of a basketball. He would be a much worse player if he stopped at being a “good” shooter and focused most of his practice time on other tasks. You’ve got to play to your strengths too.
Society plays a similar balance game when it comes to intelligence. Some people are smart. Some people less so. Do we target our weaknesses and distribute resources to the lower quartiles and move them into social and economic production? Or do we concentrate on our strengths. Eg, are only a few of us smart enough to build bridges, and spending time trying to teach the rest of us engineering is a mistake no one particularly enjoys or profits from?
It’s a big question. And we need an underlying understanding of genetics and heredity to approach it.
At the surface genetic inheritance is simple. In Mendal’s world, if a pea has one set of genes it’s yellow. Another set of genes and it’s green. But there’s complexity lurking. For something like height (80% heritability) the layman’s model is that my expected height is regulated by a genetic limit. If everything goes perfectly I’ll be 6 feet tall. But on average I’ll get sick, get stressed, or be low on some nutrient, and my actual height will end up being 5’10”. I can (and will) lose a little height, but in this model there’s nothing I can do to gain it.
But this is misleading. Within a fixed environment, a set of genetics may have an asymptotic limit. But environments aren’t fixed. Traits like height and IQ have shifted significantly over human history. Often through unforeseen technologies - language, mathematics, writing, chemistry (for vitamins and micronutrients) et cetera.
In the developed West, whenever a technological or cultural edifice is considered efficacious, societal access becomes abundant: eg, iodine supplementation, soap, air conditioning, libraries, protein access, public education.
More formally, you could call this the Efficient Culture Hypothesis: there are never culturally known ways to increase any important trait in any rich democratic country (with caveats for ethicality and scalability.) The proof of this are the phenomena that parents don’t matter and schooling doesn’t matter. You could further guess that grocery stores don’t matter, clothes don’t matter, your cell phone doesn’t matter, your car doesn’t matter. We all have access to adequacy.
The effect is profound enough that society as a whole criminalizes environments that were previously mundane:
At the turn of the 20th century 18% of all the American workforce was under the age of 16. Many of these children worked 60 hour workweeks. They slept on compressed straw, tried to stay warm under dirty patched blankets, and shared their bed with siblings, fleas, and lice.
There’s no strong science that straw mattresses directly reduce adult height or IQ. But the lack of science is epistemologically circular: there’s no way to conduct rigorous experiments because the current consensus is that conducting the experiment is unethical. Our intuition is not perfectly calibrated (eg overly-safe child rearing) But the long term trends are clear: large shifts in environment result in large shifts in “genetic limits.” People are getting taller. They’re getting smarter.
And if height and IQ are malleable on a population level, they must be malleable on an individual level. The layman’s concept that height and IQ are immutable are wrong.
And this makes heritability a mess.
Here’s an easy example. The 80% heritability for height is from Great Britain. But North Koreans and South Koreans vary in height by 6 inches and share the same ancestry. Heredity for height between the Koreas is going to be much smaller, and matched heredity for height for humans born on the surface of the Sun vis a vis Earth is going to be 0.
So, strictly speaking, if we want to know whether IQ is a function of genes or environment we cannot just look at measured heredity. If we create a wonderful environment for boys, and terrible environment for girls, we’ll find out that IQ is heritable on the Y chromosome.
Instead, what we want is theoretical heritability: to what degree do two individuals phenotypes differ in identical environments.
The thing about theoretical heritability is that it’s not even theoretically measurable. Consider the research that men and women benefit from different room temperatures (or, less controversially, that extreme temperatures will reduce performance.) If we’re looking at theoretical IQ, we’re not talking about IQ at 67 degrees, we’re talking about IQ at preferred indoor temperature. Or, to take the bigger picture, IQs in preferred environments, in the adjacent possible. [In a perfect environment all of our IQs may as well all be 400.]
Feedback Loops And Freedom
This creates a problem. Imagine two students in a mediocre public education system. Bob works hard at school. He gets a job during the summer. He stockpiles resources, and uses extra capital to purchase knowledge and other tools. His compatriot, LazyBob, avoids work of all types. He drinks alcohol to excess from a young age. When Bob and LazyBob have their IQs measured at age 22, they differ by 5 points.
But what about theoretical IQ, or g? Imagine instead we put both of them into a strict boarding school from a young age. There’s a cafeteria with abundant calories, no opportunities to socialize late, and sedulous supervision such that they both spend the majority of their day learning and studying. Let’s assume in this controlled scenario they score identically on an IQ test at the age of 22.
If this hypothetical rankles your toes, this is because we know high IQs are generally causative of good choices. The orthodoxy says two similarly IQ-ed individuals would not make such divergent choices in matched environments.
We can rectify this by adding verbiage. Our Bobs have identical neuro-effiency, but their self-control varies. The more freedom they have (eg, young and rich in NYC) the more their IQ will differ. And because the world as a whole is free environment, we know their theoretical IQs (or g) are not the same either.
Neuro-efficiency allows us to differentiate between those with low g because they have an alignment problem, versus those with low g because they have a brain lesion.
If you’ll forgive an analogy to soccer, IQ is how well you are playing right now. g is how well you would play on average if you were cloned 100 times and each clone landed in a random real environment. And neuro-efficacy would be your underlying athleticism. Even if neuro-efficacy has failure modes in most environments that result in low g, we would not be shocked to see someone with a high neuro-efficacy but low g achieve a high IQ (be an exceptional soccer player) in narrow circumstances.
[Somewhat off topic - the Efficient Culture Hypothesis predicts society will try to control external environment until those with less-adaptive alignments and those with more productive alignments have identical IQs - eg, organizations like FDA, DEA]
Generational Effects
Let’s get back to the Bobs. What happens if you iterate their scenario? Let’s assume the Bobs are very similar alien species that live on two identical planets. On planet Bob there’s significant cultural growth due to a small initial genetic difference in temperament (eg, adherence to authority.) On planet LazyBob culture is stagnant (they don’t follow rules enough to build culture.)
Over many generations IQ rises on planet Bob but stays stable on LBob. If we grab a handful of Aliens from each planet and put them in a classroom together we will find that the IQ difference between aliens is highly heritable.
But if we take an alien at birth from LBob and put him on Bob this won’t be the case. In this scenario, we expect little to no difference in expected outcome (the IQ gain was cultural) and extremely low heritability of IQ between Bob types.
Given our assumptions, we can paradoxically say that the difference between planet Bob and Planet LBob is entirely genetic, but also that there’s very little genetic difference between Bob and LBob.
Further, we can flip the whole situation on its head by slightly modifying initial assumptions. What if the causative factor of initial cultural growth is environmental (eg, food availability)? We’d likely still measure heritability due to population stratification, despite there being no underlying genetic differences.
That is, two separate scenarios with unrelated causations might be phenotypically identical. Even if we look at genetic data, we’re not guaranteed to untangle the initial causation in the feedback loop!
Intelligence Is Not Like Height
Or so says the eponymous essay by Sasha Gusev.
In sexual selection, it is difficult for genes to be adaptive when they’re overly contingent. There’s lot of variance in complex organisms, and a gene that required specific patterns from other genes would need to be incredibly adaptive to survive.
Thus, the general pattern in polygenetic traits is that each gene makes a very small additive contribution. For height, if we assume an additive model, we get 45% from direct heritability. But IQ is not like this. We get maybe 5% accuracy this way (although this number may be as high as 20%, depending on how you feel about unverified internet comments.)
But something is wrong with this model. Intelligence is not a homunculus. There’s not little men that live inside your brain, and the more of them you have the smarter you are. Instead, some aspects of intelligence must adhere to a Yerkes-Dodson curve / inverse U / Goldilocks point.
Example 1:
There’s two types of brain material: white and grey matter. White matter is bulk myelination and allows for fast and accurate thought. Grey matter is more tightly packed neurons - it allows for more plasticity.
The relationship between a tendency to build white and grey matter must, at some point in time, be zero sum. too much myelination will make us fast, but inflexible thinkers. Too little and we will not have the cognitive discipline for coherent thought.
Example 2:
Within grey matter we have dendritic spines and synapses. More spines = more connections = more thought patterns. But too many thought patterns and you’re going to be slow and scattered.
Example 3:
Each synapse relies on neurotransmitters. More neurotransmitters ≠ better brain function. There’s going to be an ideal, finite number of neurotransmitters for any task.
Our current method of bulk addition for heredity of intelligence is a problem in theory. We need to have specific models about what genes increase neuro-efficiency (eg, efficient myelination that doesn’t leak - this should increase IQ across the board.) What genes need balance (genes that affect likelihood of pruning) and genes that effect temperament (why do only some smart people like math?)
On Global IQ
Scott recently wrote about the discrepancy in IQ between nations. Of particular note is why African IQ is low.
This yielded a lot of comments with a similar flavor
I spent 18 months in a country where people are supposed to have an iq of about 70, according to the map. My neighbors and friends were mostly non-literate. They did not seem less intelligent than the people I know in my current (US) neighborhood or the people I grew up with (in the US).
or
Malawians [average IQ of 60] are 60-80% subsistence farmers.
Even a "normal" low-IQ person cannot do the implied math and long-term planning involved in this kind of farming. And in fact, economists routinely find that African small-plot subsistence agriculture is actually highly optimized; farmers make very precise choices about where to plant which seeds, which fertilizer to use, etc. Key point is basically: it really isn't true that an IQ 60 person can run a farm functionally.
The general observation is supported by a recent paper that compared Indian children who sold goods in local markets to those in nearby schools. The authors wanted to measure the transfer of math skills from market to school, and vice-versa.
For the market workers, they found:
They were proficient in solving hypothetical market maths problems and verbal maths problems that were anchored to concrete contexts. However, they were unable to solve arithmetic problems of equal or lesser complexity when presented in the abstract format typically used in school.
The opposite pattern existed in the school children:
[Although they] performed more accurately on simple abstract problems, only 1% could correctly answer an applied market maths problem that more than one third of working children solved. School children used highly inefficient written calculations, could not combine different operations and arrived at answers too slowly to be useful in real-life or in higher maths.
The paper doesn’t address IQ, but we can guess that the children working in markets have lower IQ, but not necessarily lower neuro-efficiency.
The paradox here has not gone unnoticed. I showed a draft of this essay to some friends, I was linked to a [guest] post from a Nigerian blogger Charlatan tackling the issue of national IQ. He is of the opinion that Nigerian IQ is an alignment problem:
In fact, the majority of the educated elite in Nigeria rejects, explicitly or implicitly, the scientific worldview from which modern education emerged..
Most of Africa being a highly tribal/communal/family-oriented society, there's far less pressure on the individual to prove themselves socially or intellectually worthy before enjoying the privilege of belonging
[In Nigeria] there are hardly any prestigious institutions in which admittance is based purely on merit (I know this is true [everywhere] else in the world but truer in Nigeria). The only real obstacle to getting into circles of prestige, whether academic or political, is money, pedigree, and connection
Regarding the difference between poor countries and rich ones:
I suspect it's less about raw cognitive capacities and more about cognitive propensities: what are the kind of questions about reality that engage the intellectual faculties of cognitively capable Africans versus their European counterparts?
But here’s the rub, what does Charlatan have this perspective, and most Nigerians don’t? The answer is something like high IQ. Charlatan specifically says that his IQ was the highest among his colleagues of Nigerian academics.
The feedback loop is still churning, and although we may see the exit, on our first attempt we’ve missed.
Charlatan again:
The overwhelmingly predominant attitude among the educated elite in Africa is that Africa's problem has nothing to do with cognitive disadvantage and more to do with Western oppression or bad leadership or colonialism or... whatever other external agent they can think of.
Compare this to yourself. You are the type of person who seeks out long, abstract essays. Because this particular essay is written by someone with little to zero fame, it’s likely you’re specifically interested in engaging with ideas it contains, (and not the social signal.)
I’m reminded of coaching again, and a tale a professional skier recounted from their youth of their coach repeatedly telling them to get their knees forward and put their body downhill. They knew the rule (and they probably believed they were following it) but it took them two years to have some internal epiphany and actually do it (or internalize it,) forever changing their life.
How exactly do you incept an idea into someone’s brain, or into the collective conscious? I’m not sure.
Scott Concludes his essay with:
The large difference between sub-Saharan Africans in developed countries (eg the US) and in sub-Saharan Africa demonstrates that the latter aren’t performing at their genetic peak, and that developmental interventions - again, nutrition, health care, and education - are likely to work.
I agree with this, but I will go one step further. We shouldn’t limit our optimism to just Africans. Good attitudes, alignments, and beliefs are contagious. I think the potential for improvement is across the board.
This is a small blog. I don’t always get the time to write, so every essay I publish means a lot to me. I really appreciate all comments. And if you liked this essay, please share it with others!