Honest question that keeps bothering me.
In the absence of reasonably strong natural selection pressure to select for IQ, how could IQ not be falling over time?
replies(5):
In the absence of reasonably strong natural selection pressure to select for IQ, how could IQ not be falling over time?
IQ at best measures something that correlates with SAT. And with better education, less exposure to damaging pollutants, etc. it should always be on the rise (as demonstrated by the Flynn effect; an effect which this poor paper desperately tries to refute).
IQ research has always been about proving the superiority of one race over others, this superiority doesn’t exist, but that doesn’t stop these pseudo-scientist from trying. They bend the definition of “intelligence” and device test batteries (and in this case, interpret test battery) in skewed and bias ways to manipulate results like these. Regrettably media outlets like the Popular Mechanics and lifestyle journalists like Tim Newcomb take these researchers at their words and publish their results, despite their results pretty much being lies.
It is incredibly arguable if during an obesity crisis if population wide health is actually improving and if population wide health isn’t improving that could certainly contribute to lower IQ. We’re also seeing population wide declines of health in other ways like sperm count. Food is becoming less nutritious as soil depletes. Our fish stocks being about to collapse is going to be another hit against brain health as omega 3s will become rarer in the diet.
The heritability of IQ is only well established within true believers of a pseudo-science tightly linked with the eugenics movement. Most psychologists today believe that the supposed heritability was observed because of bias within the research. And given the people who were doing these research in the 1970s and the 1980s, and their motivation for doing those, there is no question on what these biases were. Some of the researchers went so went quite far in bending the data such that it would fit their narrow—and racist—world view. They tried really hard to define intelligence such that it would make rich white people smarter, they were regrettably successful for far to long, but ultimately failed.
Your anecdotal evidence of high IQ parents (ugh!) having high IQ children is the same anecdotal evidence that sociologists have been describing for decades that high SES parents have high SES children, and is the main reason for why parents with high SAT scores are likely to have children with high SAT scores.
What IQ researchers discovered was basically the same thing that Marx described in 1867, class, however the eugenics were no communists, and instead of providing the simpler explanation, that society rewards the ruling elite, and wealth inherits, the eugenics went all conspiratorial and blamed other races for their perceived decline in society.
* IQ is real, measurable and heritable. The evidence for this is overwhelming.
* Nobody argues about the broad heritability of other human traits such as hair/eye color, height, athletic ability and the like.
* The argument over IQ is a consequence of terrible historical experiences with eugenics and racial discrimination. Many have adopted the quasi-religious viewpoint that IQ is not heritable to sidestep the discussion.
* As a consequence, social policy resembles the cycles and epicycles of Ptolemy's cosmology. Namely, all manner of social, economic and historical outcomes which are explained parsimoniously by understanding IQ as heritable are instead attributed to a Rube-Goldberg machine of racism, class warfare and the like.
* Accepting IQ as heritable does not, in an enlightened society, require acceptance of racism or classism, any more than people are forced to discriminate against those who, say, are genetically weaker athletes due to low relative VO2 levels.
* Social policy could be enhanced and better targeted by targeting those at the lower end of the IQ curve with subsidies such as basic income.
* Accepting IQ as real, heritable and measurable represents one of the only paths out of the present morass of corrupt political patronage programs around specific groups, just as rejection of Ptolemy's worldview enabled turning away from the demon-haunted world of religion.
If you're going to build a whole chain of logic, one that attempts to solve racism somewhere in the middle and ends with the "demon-haunted world of religion", it's useful to clearly define your terms first.
in both of those cases, as in all things genetic, expanding the ceiling is a far different matter. There is no known treatment I could have been given to enable me to run a 2 hour marathon. Similarly, there is no known way to cause a 100-IQ person to reliably test at a 140 IQ.
That said, progress is being made on artificial intelligence and genetics, so that could all change.
(I find it helpful to remember that lipstick-wearing is highly heritable despite zero genetic determination, and number of toes isn't very heritable at all despite total genetic determination.)
In particular, you can't convincingly go from discussing the seemingly profound effects acknowledging IQ heritability will have on racism, in order to avoid "demon-haunted" religious arguments, to a shrug and a handwave about genotypic (and epigenetic) effects vs. environmental effects. With due respect to your good-faith attempt to establish a logical baseline to this whole situation, the demons are haunting your argument, not those of people who'd push back on it.
It's an earlier rebuttal and you can find more precise and current ones now, but Ned Block's heritability piece is a good starting point for this stuff (you can just Google for "ned block heritable", the SERP will be dozens of links to it.)
> I don't understand how your logic holds together once you concede that heritability doesn't mean "genetically determined".
And you wrote:
> You literally just said that you were using "heritability" as a synonym for "genetic determination". No, you can't do that.
I'm not sure which sentence I'm supposed to take as you saying what you mean, but yes, I can say I'm using "heritability" as a synonym for "genetic determination."
And, of course there is plenty of evidence that IQ is genetic. That's most of the reason why it's become a taboo area of research. If people were sure it was a waste of time, they'd just tell researchers to go ahead and check. Instead, they taboo it because they're afraid of what it would mean for their view of society if it turned out to be true, which it surely is.
As I mentioned in another thread, your claim that it's not genetic should not be the prior here. That would be like me claiming that people's maximum height being environmental should be the prior. It's just preposterous. Of course physical traits are primarily genetic. The brain is a physical object, therefore its structure is primarily genetic.
Later
You've extensively edited your comment. In response to those edits: if you look back at my comments, I think you'll see that I haven't made a claim about genetic determinism at all, only that the evidence you've presented doesn't support it.
Or in other words, the reason you're not smarter is because nobody's invented a surgery to make you smarter yet. And the reason you're not less smart is that nobody's hit you over the head with a rock. If either of those scenarios happened, your ancestry wouldn't get to object much.
If you want a theory of intelligent to include a notion of general intelligence which can be measured, you must be able to defend which aspects of behavior falls in the category of intelligent, and which not.
Playing chess and jumping on furniture both require plenty of cognitive skills, and brain functions to work together and produce a singular outcome, both are goal driven, both takes years of practice, both have varying skill levels.
Now the cognitive functions these skills require may both be inherited, you may even find the specific genes which encodes either behavior (and name them the furniture jumping gene and the chess playing gene if you will). However when you assign chess playing as intelligent but not furniture jumping, then you’ve made an arbitrary choice, which you need to justify. (You also have the option of not defining intelligence to begin with; which what I personally would pick).
But more importantly, even if you find your justification, you’ve only found one gene of intelligence which inherits, you haven’t found a gene for general intelligence, so you haven’t shown that intelligence is determined by your genes, only the ability to play chess well.
Then when you find all the genes for all behavior you consider intelligence, you still haven’t shown that they co-inherit with each other, that is, you haven’t shown that people with the chess playing gene tend to also have the sudoku solving gene, and the IQ test taking gene, etc. For there to be a single general intelligence, and for this general intelligence to be determined by genetics, than this is what is required. Unless of course general intelligence is a real thing and there is a gene for it which allows you to play chess better than others, solve Sudoku faster than others, answer more questions on IQ tests correctly, etc. But this is a rather extraordinary claim, don’t you think?
I agree with that reasoning! We defined intelligence the way we do because it "works." If jumping on chairs were what advanced modernity, we would test for that instead. And, that too would "work" because it would surely be a marker for people who were likely to be successful in life.
Social sciences aren't going to be able to provide specific answers to your questions in the near term. No, there is no single gene or trait that codes for "intelligence" as we define it. But, that does not mean we can't come up with intelligence tests which correlate strongly with that definition and also correlate strongly with various measures of success in life. Such measures also correlate strongly with society-wide success (measured by a group's progress along the tech tree).
Actually I’m gonna repeat a couple of paragraph from the first post you responded to: https://news.ycombinator.com/item?id=35517130
> Your [faeriechangling] anecdotal evidence of high IQ parents (ugh!) having high IQ children is the same anecdotal evidence that sociologists have been describing for decades that high SES parents have high SES children, and is the main reason for why parents with high SAT scores are likely to have children with high SAT scores.
> What IQ researchers discovered was basically the same thing that Marx described in 1867, class, however the eugenics were no communists, and instead of providing the simpler explanation, that society rewards the ruling elite, and wealth inherits, the eugenics went all conspiratorial and blamed other races for their perceived decline in society.
(For what it's worth: research suggests that adopting low-SES children into high-SES households is associated with as much as an 18 point increase in IQ test scores.)
You're selectively citing research on adoption. In fact, there's plenty of research showing that gains are transitory and parental IQ is a better predictor of IQ in late teen years than is the high-SES environment. This whole "mystery" is what prompted folks to ask Jensen to start studying Head Start, as it wasn't clear it was doing any good. The problem is these interventions don't work. They don't work because IQ is genetic.
"That doesn't work because IQ is genetic" doesn't even make sense as a sentence. It implies that something being "genetic" means it's immutable. That's not even how genes work. But it's how people thought they worked in the 1960s, which is where your cite comes from.
Here's a nice take-down of him that took me 3 minutes of googling to find: https://cremieux.medium.com/is-eric-turkheimer-a-scientist-e...
I remember my first university assignment when studying psychology back in 2008. It was an essay on the nature vs. nurture debate. I remember going through the sources and deeming the debate kind of stupid. Then I got to Turkheimer, particularly the legendary 2000 article of “Three Laws of Behavior Genetics and What They Mean” which begins with:
> The nature-nurture debate is over. The bottom line is that everything is heritable, an outcome that has taken all sides of the nature-nurture debate by surprise.
And concludes with:
> The gloomy prospect [non-shared environment between siblings accounting for a large part of behavioral variability] looms larger for the genome project than is generally acknowledged. The question is not whether there are correlations to be found between individual genes and complex behavior—of course there are—but instead whether there are domains of genetic causation in which the gloomy prospect does not prevail, allowing the little bits of correlational evidence to cohere into replicable and cumulative genetic models of development. My own prediction is that such domains will prove rare indeed, and that the likelihood of discovering them will be inversely related to the complexity of the behavior under study.
Later in a 2003 study he then goes on and demonstrate that almost all of the variability can be explained by environmental effects (E) and genetic and environmental interaction effects (G × E). None of the previous readings even considered interactions and always concluded with x% E + (100 - x)% G for some x. (EDIT: Catching up my reading I actually see that more recent behavioral geneticists are even using G × E² in their models, that is, the environment also interacts with it self, and that interaction also interacts with you genotype, making for much richer models).
I turned in my paper concluding that obviously there was a flaw in previous studies that don’t look at interactions. Like why is this even being debated any more? I off course got a failing grade for the essay, being of low SES (sorry IQ) my essay skills obviously lacking as I didn’t have the skill (sorry intelligence) to formulate a coherent argument. Thankfully my boy Eric Turkheimer came to the rescue by concluding that actually in a high learning environment like a university in a country which grants equal education to everybody that my skills can be improved (sorry, I mean, my intelligence is malleable), so that I could graduate 3 years later with a first grade.
No, nobody can talk bad about my boy Turkheimer.
* Good genetics, bad environment = bad outcome
* Bad genetics, good environment = bad outcome
* Good genetics, good environment = good outcome
* Bad genetics, bad environment = bad outcome
So, it's basically an "and" gate.
I see nothing wrong with this reasoning, and it makes perfect sense to me. A couple points, however.
1. You'd still have to ask the question of which of the variables is malleable.
2. There would remain this question along the lines of, "let's say you took 1000 children from low-SES environments and put them in high-SES environments. What happens?" My recollection of the literature on this is it's somewhat sparse (because this doesn't happen that often), but that there's a strong regression to the genetic intelligence in the teenage years. BUT, even if you argue all such studies are methodologically flawed, the US government, with its $N trillion budget could easily simply run this experiment and find out what happens. Why don't people advocate to run this experiment?
Edit: Just to sidestep bad-faith responses, here's how the experiment would work. You run a program where all low-SES babies put up for adoption starting on a random day become eligible for something such that high-SES families who adopt them get some massive tax break or even subsidy while raising them. They would be required to show proof they spent $Nk per year on private schools, that they live in a high-SES neighborhood the entire time, and there would be home visits to ensure the kid is being treated appropriately by the parents. Any families where this isn't the case would be excluded.
Now just to clarify, G + E is a different model from G + E + G×E. Many twin studies in the past century were done on a pretty homogeneous demographic, across a very slim slice of SES (mostly inside high SES; as you correctly pointed out). This skewed the models such that it completely missed the G×E part, this is, if you don’t measure across different SES, you’ll miss how SES interacts with genotypes. What Turkheimer did was actually measure heritability inside low SES, and his results were that in a G + E model, the proportions were flipped. That is, instead of G=60% and E=40%, he and his team found E=60%. When your get results that flip in this way, it is a pretty clear indicator that you have interactions between your main effects (G and E), so Turkheimer fitted a model which includes the G×E interaction[1] (which all researchers with some level of statistical literacy would do) and found that almost all of the variance previously attributed to genes, would perish into the interaction effects.
You can read the study here. The methodology is not that far off from what you are proposing (just without the controlled interventions; which is bound to cause some biases anyway). https://www.researchgate.net/publication/8997472_Socioeconom...
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1: Note the models are a bit more complicated than G+E. Usually they use an ACE model, with Genotype (A), shared environment (C), and non-shared environment (E; also known as gloomy prospect), and than model A + C + E. In Turkheimer, et. al. (2003) the model was s*SES + A*(a + a'*SES) + C*(c + c'*SES) + E*(e + e'*SES) where a,c,e are the main effects of A, C, E; s the main effect of SES; and a', c', e' are interactions of a,c,e with respects to SES.