Intelligence is not like height

https://theinfinitesimal.substack.com/p/no-intelligence-is-not-like-height

by Schiphol • 2 years ago

64 157 2 years ago

theinfinitesimal.substack.com

hawkice• 2 years ago

This article is very invested in constant mockery. As someone who just wanted to understand better, it made it a tedious read.

lnxg33k1• 2 years ago

The real joke is quoting psychologist to counterpoint students of races? (I guess anthropologists?) Or quoting psychologists about anything, regardless

someguydave• 2 years ago

The author has a known ideological axe to grind, read his tweets

rowanG0774• 2 years ago

I don't understand the point of this article. That IQ is different then height? Oke great and? I have never seen anyone claim they were the same.

Kye4• 2 years ago

I have! We're all singular entities with a narrow lens into the experiences of others, so it's inevitable we'll never encounter things that others encounter way too much.

rowanG0774• 2 years ago

Where do you encounter something like this? Could you point it out to me? If it deserves such a ridiculous rebuttal I would expect to be able to easily find it online.

randomdata12• 2 years ago

Interesting. How would one even go about expressing the idea that height and intelligence are literally the exact same thing in such a way that someone would want to talk about it?

bumby2• 2 years ago

It's simply a claim about heritability of intelligence. In other words, "Intelligence isn't inheritable like height" according to the author. There are certainly plenty of people who claim that genetics explains a large part of intelligence.

rowanG0774• 2 years ago

It's very hard to look at heritability and make a genetics conclusion. That's because two people's genes fuse to make a new person. And this process could be chaotic for some traits. So even if trait x is genetic it may not be possible to predict that trait in the children based on the trait in the parents.

So it's possible intelligence is genetic even if heritability suggests it isn't. What would be interesting is to look at monozygotic twins. If their IQ scores are more highly correlated then siblings or non-monozygotic twins it's a clear indication intelligence is genetic. But I imagine that the sample set is tiny.

zzzeek4• 2 years ago

I have never seen anyone claim they were the same.

well read some of the other comments coming in here. I dare not upmod this article on a site like Hacker News.

bitwize• 2 years ago

It's to debunk the pseudoscientific nonsense -- rooted in racism and white supremacy -- that IQ is a largely genetically determined trait which is then often used to assert that certain ethnic groups are on average smarter or stupider than other ethnic groups.

poszlem• 2 years ago

White supremacy that claims that asians have the highest IQs. Makes all the sense in the world.

rjsw• 2 years ago

More that because IQ isn't genetically determined any data that makes it look like certain ethnic groups are smarter or stupider than other ethnic groups must be wrong.

The argument on both sides misses out that the IQ data seen could be a result of other factors that are only indirectly associated with an ethnic group, such as that group being descended from people who were enslaved or who practiced polygamy or who don't prevent first cousins from marrying.

alexey-salmin3• 2 years ago

A statement like "IQ is heritable" is neither science nor pseudoscience, it's just a statement that is either true, false or e.g. 80% true with 20% determined by other factors.

Doing studies to prove or disprove it, like ones on separated twins referenced here in comments -- this is science.

Saying that this statement is false because it's racist -- this is pseudoscience.

podgorniy• 2 years ago

Add a perspective of IQ of separated monozygotic twins

https://www.sciencedirect.com/science/article/pii/S019188692....

---

UPD and this one https://link.springer.com/chapter/10.1007/978-94-011-6129-9_...

feedforward2• 2 years ago

These studies are very flawed for several reasons, the main one being "separation" which is a very loose definition of separation. If identical twins grow up together but some time in childhood one is sent to live with a relative, before a later reunification, this is called "separated". It does little to separate nurture from nature.

Which makes sense - how many identical twins are separated at birth? Even if they were, it is unlikely one would be sent to Cambridge and one to rural Nepal (one of the lowest places for these IQ studies).

gwervc• 2 years ago

I read a large part of this article. While it appears to be really serious notably by the vocabulary used, like other articles trying to "debunk" genetic intelligence it pushes too hard its narrative.

In particular, two semantic tricks are used. First, the fact that current genetic markers aren't a good prediction for IQ heritability is used as an argument against it. The other likely explanation that our understanding of those markers is widely incomplete is not explored.

Second, is the more common "IQ isn't intelligence" trick. Sure, the measure doesn't encompass everything that is making intelligence, but it is still a somewhat interesting proxy as there is a high correlation between intelligence and IQ.

bokoharambe• 2 years ago

It just seems strange to me that, like in the case of mental illnesses such as depression or Schizophrenia, scientists insist on looking for genes or even GWAS correlations and just aren't finding anything. At a certain point, you have to wonder if something other than genetics accounts for the observed heritability.

sillysaurusx• 2 years ago

Environmental factors are certainly a part of those. I heard a story of someone being stranded at a lighthouse alone for many months, and he had a break from reality which affected him the rest of his life. It's always seemed interesting that the brain can be damaged by stress rather than physical injury – or that perhaps stress causes physical injury.

practicemaths4• 2 years ago

Maybe it isn't entirely a hardware issue. Maybe it is a software issue.

Where do persons get their software from? The environment. Observing how their parents/family/etc interact.

I think it's fair to say that communication matters and that communication & experiences will have an affect on peoples perceptions.

gruez• 2 years ago

like in the case of mental illnesses such as depression or Schizophrenia, scientists insist on looking for genes or even GWAS correlations and just aren't finding anything

Source? Wikipedia says:

A central point of debate on GWA studies has been that most of the SNP variations found by GWA studies are associated with only a small increased risk of the disease, and have only a small predictive value. The median odds ratio is 1.33 per risk-SNP, with only a few showing odds ratios above 3.0.[1][46] These magnitudes are considered small because they do not explain much of the heritable variation. This heritable variation is estimated from heritability studies based on monozygotic twins.[47] For example, it is known that 40% of variance in depression can be explained by hereditary differences, but GWA studies only account for a minority of this variance.[47]

which admittedly isn't airtight proof for "depression is 100% genetic!!1", but isn't exactly "just aren't finding anything" either.

Blot28823• 2 years ago

but it is still a somewhat interesting proxy as there is a high correlation between intelligence and IQ.

How does one find a definition of intelligence that allows us to correlate it to anything? My understanding is an IQ is defined and intelligence is not.

AlanYx• 2 years ago

Psychometric intelligence ("g") is defined correlationally viz. cognitive tasks; that is, the definition is itself a correlation. But it's robust in the sense that it correlates beyond the correlations used in its definition, e.g.: https://www1.udel.edu/educ/gottfredson/reprints/1997whygmatt...

Xen9• 2 years ago

One must add that IQ & height distributions ALSO look the same despite the latter and artificial one being a good proxy for intelligence.

karol• 2 years ago

Agreed.

It's a classic post-modern 'we cannot define intelligence even when we see it'. IQ is such a bad proxy for intelligence! There's no gene for IQ! Regardless, let's keep digging in genes because that's the established science and grants are coming our way. This is the best available study to date!

If that's not a great example of looking in a wrong place, I am not sure what is.

hirvi748• 2 years ago

I've often wondered if IQ is in protected state in the field of psychology.

What I mean: Psychology cannot afford for IQ to be disproven or invalidated. Doing so would completely undermine a significant portion of field. It would be like if evolution was disproven in biology -- absolutely gutting. (Just an analogy, don't kill me).

I see this when people bring up Lewis Terman's studies on giftedness or Richard Feynman's IQ score of ~124 -- especially the latter.

People come rushing out of the woodworks with statements like, "Well, Feynman was probably goofing off," "Feynman's result cannot be accurate -- he was a Putnam Award winner in high school," "Test were different back then," etc..

Sure, all of those could be right, but we only can operate off of what we know. The actual cold truth? We will never know.

However, like a knife through the heart, people refuse to even accept Feynman's score as a possibility. Feynman was an exceptional person. Exceptional people are outliers -- perhaps in more than one way.

Personally, I think it crushes people's souls to know that a famous theoretical physicist scored lower on an IQ score than expected, but still accomplished more in life than they did.

That is why I personally believe life is the one true IQ test. You get one shot. One's true intelligence is what you do with it. But hey, maybe my IQ is too low?

cool_dude852• 2 years ago

Lol, who ran a correlation analysis between intelligence and IQ to convince you that the "correlation" between the two is high?

alexey-salmin3• 2 years ago

Lol, who ran a correlation analysis between intelligence and IQ to convince you that the "correlation" between the two is high?

Well you can ridicule this statement if you like, but I can suggest a good-faith approach to this question. For example you can trying coming up with a few definitions of what intelligence could be and then look for correlation between this definitions and IQ.

I can go first: intelligence can be reasonably defined as "knowledge and skills to be successful in life, i.e. have higher-than-average income". This definition of intelligence strongly correlate with IQ. There are other possible approaches but all the ones I can think of (e.g. results in math tests) have at least some correlation with IQ.

Now how do you see intelligence? Does it correlate with IQ?

blackbrokkoli4• 2 years ago

Who ever measured the "correlation" between intelligence and IQ and how?

...given that intelligence is not only abstract, but also not defined consistently?

bena• 2 years ago

I mean, technically, height is not like height either.

One's height is not fixed, even in a given day.

But I get his point. Kind of.

Intelligence is more like speed. Speed can be affected by multiple things. Once you run X fast, it doesn't mean you'll always be able to run that fast. One's top speed is more of a range than a fixed point.

And we measure speed all day long.

Intelligence is a thing. People have it to different degrees. People often mistake it for knowledge. And IQ is a way to measure at least a part of it.

AmericanChopper3• 2 years ago

The thing that all the moralisation around IQ misses, is that IQ is a serious problem in a lot of places around the world, and turning it into a career-ending taboo topic basically ensures that it goes completely unaddressed. I’ve worked with governments and companies in quite a few developing countries around the world where the average IQs are between 1-2 standard deviations below 100, and that problem is right up there with corruption when it comes to what’s holding these countries back. It would be great if solutions to this problem were being studied, but idiots like this author basically guarantee that will never happen.

foobarian• 2 years ago

but idiots like this author basically guarantee that will never happen.

Could also be intentional

darby_nine7• 2 years ago

The use of IQ is a problem, or are you taking the metric seriously?

zzzeek4• 2 years ago

I bet the solution is heavy on "access to clean water, food, security from war and violence, and education", amirite? sure let's fire up the "IQ science" machine to give us reasons to not have to do something so boring as to improve the lives of those living in developing nations.

marcuskane2• 2 years ago

I think you've misunderstood the comment you're responding to.

They're suggesting that to give the optimal assistance to those countries, the IQ of the current adult population needs to be considered as an important variable in the equation, but it's taboo and stigmatized to discuss or acknowledge, so the people get sub-optimal solutions instead.

If you want to help some community in need, but you're not allowed to address certain taboo topics- IQ, substance abuse, STDs, domestic abuse, religious beliefs or cultural norms, whatever may be relevant for that group, then you're probably not going to design your programs for assistance in the best way.

horns4lyfe• 2 years ago

And if you don’t take into account characteristics of the population you’re trying to introduce these things to, you’ll fail.

tsimionescu6• 2 years ago

Isn't an IQ of 100 by definition the average IQ of the country studied? What do they define as an IQ of 100 if not the average of their population, what are the tests calibrated on?

AtlasBarfed• 2 years ago

Obviously 100 is calibrated to western populations.

I believe IQ has also risen steadily with time in the west. It might have risen an entire standard deviation. It's called Flynn's effect, 3 points per decade.

That can't be explained by pure heritable genetics. Epigenetics possibly, nutrition, better education systems, higher information dissemination.

antisthenes• 2 years ago

I’ve worked with governments and companies in quite a few developing countries around the world where the average IQs are between 1-2 standard deviations below 100, and that problem is right up there with corruption when it comes to what’s holding these countries back.

Also consider how much brain drain contributes to this. Anyone in those countries who is smart enough to recognize this will just emigrate to more developed countries, and their home country will never get to benefit from their (relatively) smarter people.

So the country's IQs might be just about average, but if their top deviation is constantly leaving...you have a negative feedback loop through no one's fault.

A_D_E_P_T• 2 years ago

The heritability of IQ, from twin studies and via other traditional methods of measuring heritability, is way higher than the author of that article implies. It's as high as 0.8. (80% of variance down to genetics.) See, e.g.: https://pubmed.ncbi.nlm.nih.gov/23919982/

If you measure heritability only via SNP studies, it looks a lot smaller. This is what's called the "Missing Heritability Problem." See: https://en.wikipedia.org/wiki/Missing_heritability_problem

This problem is, as yet, unsolved. There's a lot we don't know about traits that are governed by "many genes of small effect."

The author of the article probably knows better and is being disingenuous, but it's flat-out wrong to say that intelligence is only weakly heritable.

darby_nine7• 2 years ago

Of course, IQ only weakly correlates to the intelligence that people actually refer to colloquially. It doesn't test for most behaviors that people do consider intelligent, and it tests a bunch of stuff completely unrelated to intelligence (e.g. cultural trivia).

jejeyyy77• 2 years ago

this isn't accurate at all.

tacitusarc• 2 years ago

No legitimate IQ test involves cultural trivia. It’s pretty much all Raven’s Progressive Matrices though that has it’s own issues.

dtech• 2 years ago

IQ is only a narrow specific type of intelligence biased to western education indeed, but it certainly isn't a pop quiz like you make it our to be

Workaccount23• 2 years ago

unrelated to intelligence (e.g. cultural trivia).

When you think those facebook "test your IQ!" tests are actual IQ tests....

noch• 2 years ago

IQ only weakly correlates to the intelligence […] it tests a bunch of stuff completely unrelated to intelligence (e.g. cultural trivia).

These are unfortunate myths. See the following on IQ testing, relationship of various tests to general intelligence, and the absence of cultural bias in testing:

- Standardized exams measure intrinsic ability, not racial or socioeconomic privilege https://milkyeggs.com/society/standardized-exams-measure-int...

- Fair and Square: A Conclusion on IQ Test Bias https://menghu.substack.com/p/fair-and-square-a-conclusion-o...

"Generally, the most commonly used IQ tests aren’t biased or only minimally biased as to be of no practical value."

- Bias is Often Unpredictable https://www.cremieux.xyz/cp/140810182

"Bias does not simply mean that a measure gives different scores to different groups. This is one of the most common misunderstandings about “bias”. What it really means is that members of different groups obtain different scores conditional on the same underlying level of ability."

- The Relationship Between the Scholastic Assessment Test and General Cognitive Ability https://sci-hub.st/https://journals.sagepub.com/doi/abs/10.1...

"Furthermore, empirical evidence suggests a substantial relationship between the SAT and g. In a study of 339 undergraduates, Brodnick and Ree (1995) used covariance structure modeling to examine the relationship between psychometric g, socioeconomic variables, and achievement-test scores. They found substantial general-factor loadings on both the math (.698) and the verbal (.804) SAT subtests."

- Systemwide Review of the Report of the Academic Council’s Standardized Testing Task Force (STTF) (2020) https://senate.universityofcalifornia.edu/_files/underreview...

theptip• 2 years ago

What do you make of this section that claims recent research has identified an upper bound on the genetic component?

…prediction accuracy depends on sample size, could the findings drastically change with more samples in the future? In fact, through the magic of statistics, we actually know that this claim will always to be true. We know this because we have estimated a parameter called molecular heritability, which tells us the upper bound on what a genetic predictor could ever achieve. Molecular heritability comes in two forms. “Population heritability” is a non-causal measure of the overall correlation between all genotyped variants and the trait, and it is estimated in large populations of unrelated individuals. Population heritability includes direct genetic influences on the trait that we typically think of as “genetics” but it also includes a lot of other correlated stuff that we typically think of as confounding, like cultural influences on the trait from relatives or prior generations (including the effects of parenting or dynastic advantages) or biases due to population stratification. In contrast, “direct heritability” is a measure of the specific genetic influences that are acting within individuals, and it is estimated in a large number of families. Direct heritability is immune to many sources of environmental confounding and, with some assumptions, can be interpreted as an estimate of causal genetic effects (for theory and derivations see [Veller et al. (2023)])

feedforward2• 2 years ago

The heritability of IQ, from twin studies and via other traditional methods of measuring heritability, is way higher than the author of that article implies. It's as high as 0.8.

No one here can seem to be able to prevent an LLM from saying 3+5 is something other than 8, yet you talk about "IQ" as if some test cam boil down human brains to one integer and then rank them.

Also if one person is born in a stable, educated house, and another in a poor unstable house where they are not educated, how is environment separated from heritability? People try to make social science studies to do this, but the problem is they have limited data to draw on.

This ideal of a Calvinistic Brahmin chosen people is rooted in parasitism and idleness. We can have a meritocracy society where everyone starts on the starting line, or we can have one where at birth someone is either on the worker bee or rich kids of Instagram born on third base path. The idle class aristocratic parasitic view favors the very weak idea of heritability - some hidden genetic change in the past 50,000 years after behavioral modernity.

hirvi748• 2 years ago

I am not disagree with what you said, but I wanted to point one thing out:

how is environment separated from heritability?

It isn't. That's why heritable traits are different than genetic traits.

Alcoholism is a heritable disease but is not a genetic disease. One cannot suffer from alcoholism in an environment where alcohol does not exist.

philipov2• 2 years ago

Anyone who wants to look at heritability numbers should make sure to watch these lectures first. Heritability is often a misleading stat, because it has an unintuitive definition. Sapolskiy covers common failings of heritability numbers, as well as confounding factors for twin studies.

https://www.youtube.com/watch?v=OareDiaR0hg

https://www.youtube.com/watch?v=FZ6D3-XHmEk

Full Lectures: https://www.youtube.com/watch?v=NNnIGh9g6fA&list=PL848F2368C...

An example of how non-intuitive heritability is: whether a person wears earrings or not would be a heritable trait if we're looking at mid-20th century America, because the variability is entirely explained by whether you're male or female.

Heritability is unable to identify whether a trait is caused by genetics, only whether the variation correlates with genetics.

rosmax_133711• 2 years ago

It turns out molecular genetics has (for lack of a better word) thoroughly debunked [the view that Intelligence is significantly heritable].

There is also a replication crisis in post-modern science.

Not to mention, is it even legal, let alone reasonably possible for a study to publish in a real journal the view that Intelligence is heritable, in particular when it concerns race? This topic is arguably the in the top 3 forbidden taboos of western society. In European countries you can face charges of hate speech for even suggesting this, let alone dedicating a life of study regarding a certain conclusion.

That an article like this amounts to semantic evasion of the matter, like the post by gwervc here describes, does not give credibility to the side which continues to maintain that evolution has [by all significant measures] stopped at the neck.

brookst2• 2 years ago

In European countries you can face charges of hate speech for even suggesting this

Source?

randomdata12• 2 years ago

https://news.ycombinator.com/item?id=41368174

rosmax_133711• 2 years ago

https://www.svt.se/nyheter/lokalt/sormland/hd-tar-upp-fallet...

SVT is the Swedish government news agency. The article describes a politician facing charges for suggesting that South Sudanese people have a lower IQ.

tsimionescu6• 2 years ago

No reasonable scientist would study a correlation between a physical trait (intelligence) and a socio-economic concept (race). It would be like studying if height is correlated with "proper grammar".

Edit: race, not "rave"

rosmax_133711• 2 years ago

Is race a socio-economic concept? Can you explain what you mean by that?

tourmalinetaco5• 2 years ago

While “rave” is a misnomer, being applied almost exclusively based on skin color, haplogroups are a well defined aspect of genetic study and are very well defined geographically. It’s why the Germans look so distinct to Australians and so on, because different genetics found their footing in different areas. Claiming they are based solely on “socio-economic” factors is wildly incorrect and wildly racist. To what authority does someone’s social and economic standing define their genetics?

DiscourseFan12• 2 years ago

Not to mention, is it even legal, let alone reasonably possible for a study to publish in a real journal the view that Intelligence is heritable, in particular when it concerns race?

What do you mean by race? Because race isn't genetically determined, its socially determined--two people of a very different "race," can actually be quite closely related genetically, its just that their appearances differ.

does not give credibility to the side which continues to maintain that evolution has [by all significant measures] stopped at the neck.

Its not that evolution has or hasn't stopped at the neck, its that the IQ test as a single objective measure of intelligence, like measuring height, is incredibly flawed since it has changed dramatically in the decades when these studies have been conducted.

Whether or how someone is intelligent cannot be measured empirically by a single standard since purely intelligible things, like concepts, math, artistic ability, by nature cannot have an empirical appearance. But you know if someone is smart, and you know it because they tend to do things that are smart. But that's only helpful at the level of a single individual, its not something that can be measured population wide.

post-modern science.

The most "post-modern" thing here is your comment, which you clearly wrote without having actually read the article thoroughly.

rosmax_133711• 2 years ago

IQ remains one of the most highly predictive traits you even can measure from someones psychology, predicting crime rates, happiness, divorces. Just about everything actually is predicted by IQ in someones like, to an extent to which philosophical questions about determinism even can be brought up in discussion.

Race is genetically determined. Are you suggesting that for example breeds of dogs can swap from Labrador to Golden Retriever based on vibes during their upbringing. The term "black" as a racial group is of course an extremely crude and large genetic grouping, much like saying that perhaps "retrievers" are a race of dogs. Nonetheless, groups remain genetically determined.

stonethrowaway• 2 years ago

HN is going to have to address bait topics (and bait “science”) more than bait clicks. The author has an axe to grind with a certain subset of the population and this board is caught in the cross fire.

passion__desire7• 2 years ago

Annecdata : Our primate brains has random number generators to keep our head moving and scanning the environment for threats (there a possible veritasium video on this topic). But my friend in university had a possible (gene?) modification which allowed him to focus on a particular task intently. He could ignore distractions very easily and unsurprisingly he could grok biology and physics textbooks like crazy. The fact a spider with salt sized brain can weave a web without seen examples is a proof that genes do have effects on brains and capabilities.

passion__desire7• 2 years ago

This is the video. https://youtu.be/RY7hjt5Gi-E?t=564

DiscourseFan12• 2 years ago

Of course, but not anything that we can use an IQ test to measure, especially at a population wide level.

CFLAddLoader• 2 years ago

Straightforward intelligence boosting genes are valuable enough that unless they are very recent, they should already have spread everywhere.

It's more likely that developing brains have a huge number of potential tradeoffs to make for what tasks they are good at and how much energy they use. Genetics and epigenetics are merely one of the tools a brain uses to decide what shape it takes, and aren't even close to the whole picture.

graham127851• 2 years ago

You could say the same about genes in tons of other areas, and you'd be completely wrong. That's now how evolution works. "Beneficial" genes don't just get to spread everywhere quickly, otherwise parapatric speciation could never occur. Read the wikipedia article for Parapatric Speciation. What does "incomplete geographical barriers" remind you of?

Evolutionarily our intelligence IS very recent.

Workaccount23• 2 years ago

The first line of the first study the author references as "the largest genetic analysis of IQ scores":

Intelligence is highly heritable

The author then writes this whole piece without once mentioning twin studies. Which is kind like writing about climate change and not mentioning CO2.

Also the author works for Harvard, which has been speed running their credibility into the ground as of late, for exactly the kind of highly politicized topics like this one.

Zpalmtree• 2 years ago

what a garbage article, he spent so much time being mad he forgot to be convincing

blackbrokkoli4• 2 years ago

The section Unlike height, no one knows what IQ is actually measuring, buried deep in the article, is really all that's needed. "Height" is a well-behaved non-changing property that is meaningful, "IQ" is none of these things. Some fun facts:

- The variation between IQ tests done by the same individual is significantly higher than almost any reasonable cross-group variation (men vs. woman, country A vs. country B, doctors vs. craftsmen, ...)

- The original IQ-test had to use a mathematical trick to cut off "growth of intelligence" at exactly 16 years old, which totally incidentally was the age where mandatory schooling ended for the relevant population.

- The famous "Termites" study which attempted to use IQ to predict the future upper crust of society by testing a large number of children failed to predict any Nobel price winners, but excluded two future Nobel winners (they were too dumb)

- IQ is totally unchangeable and static — nonetheless, you are forbidden from studying or practicing for IQ tests.

So to me, it's not particularly surprising that genetics disappoint in predicting IQ — given that they also fail at predicting other nonsensical and ever-chaning values such as whether I liked today's dinner..

busyant• 2 years ago

- The variation between IQ tests done by the same individual is significantly higher than almost any reasonable cross-group variation (men vs. woman, country A vs. country B, doctors vs. craftsmen, ...)

I don't know about your other points, but this doesn't seem believable.

Is there a reference for this?

teshier-A• 2 years ago

Well it does sound reasonable but I don't think it is as convincing as OP thinks. If you take two IQ tests in your life and get 130 and 138, I imagine the variation to be higher than the group vs group comparisons he mentioned (maybe not doctor vs craftsmen? it is after all very correlated to education level) but it doesn't mean the measure is "nonsensical and ever-chaning values such as whether I liked today's dinner.."

blackbrokkoli4• 2 years ago

Can't find the one I actually had in mind right now, but here is one where they run various cognitive tests on high-IQ-value individuals, with performance regularly dipping below population average: 10.1007/s12207-021-09417-x

bendigedig• 2 years ago

I find it hard to understand why we think it is possible to assume that the influence of genes and influence of environment are independent in this manner.

Given that we know that the environment affects how genes are expressed; and given that it's the genes that happen to be expressed which have more of an impact on intelligence than the genes one happens to 'have', then surely all research in this area which fails to account for interaction between (various) environmental impacts and genetics is bound to be futile?

hirvi748• 2 years ago

I am surprised so many cling to the idea that intelligence is highly genetic when we have demonstrated before that so many things can be done to completely nullify any genetic advantage.

I am not saying there are no genetic contributions, but clearly any genetic benefit is highly contingent on many external factors.

For example, I doubt Terrance Tao would have become the genius he is today if he were raised in conditions like many children in the Romanian orphanages in the 1980s and 1990s.

Workaccount23• 2 years ago

I think a chronic problem is people and studies starting with a false premise without even realizing it.

"Affluence is strongly correlated with higher IQ, therefore IQ is a socioeconomic problem"

You have the classic example of the smart person saying "I grew up in a house with a lot of books"

And then everyone reflexively takes away "Having lots of books around when you are young leads to more success!"

But virtually no one goes to "Smart people tend to have lots of books in their home, and they also tend to give birth to smart children, who are unsurprisingly drawn to reading books"

You see this everywhere.

randomdata12• 2 years ago

we have demonstrated before that so many things can be done to completely nullify any genetic advantage.

If the genetic advantage is nullifiable, how can it exist?

When people compare intelligence to height, they are speaking with respect to maximum potential. As far as we know, genetics do dictate how tall you can potentially become. Environmental factors may leave you shorter than your potential, but if we were able to expose all people to a perfect growing environment, they would not all end up being the exact same height. They would only grow to the limit dictated by their individual genetics.

If a supposed genetic advantage with respect to maximum intelligence potential is nullifiable, that surely implies that all humans have the capability of reaching equal intelligence? But then what genetic advantage is there to speak of?

hirvi748• 2 years ago

If the genetic advantage is nullifiable, how can it exist?

"Nullify" was a bad word to use, so thank you bringing that to my attention.

The genetic advantage is environmentally dependent. In other words, having the right genes may be necessary, but the right genes alone are not sufficient.

they are speaking with respect to maximum potential.

And how is the maximum potential determined? Maximum potential seems to me like some kind of ethereal value based on comparative associations to others with the same/similar genes. "Feynman has these genes and was a genius. If you have these genes you should be a genius too." We both know genetics and intelligence do not work like this.

Environmental factors may leave you shorter than your potential

Human Growth Hormones can also leave you taller than your "potential" if administered prior to your growth plates forming. So, the "potential" value is apparently not static because environmental values can increase/decrease the potential.

people to a perfect growing environment, they would not all end up being the exact same height.

We can assume this, but we cannot possibly confirm this. Albeit, I do agree with you on this, rationally speaking.

But then what genetic advantage is there to speak of?

The genetic advantage would be having the appropriate genes in the appropriate environment.

throwaway99172• 2 years ago

Many of these studies don't account for test/retest reliability of IQ tests. Height is pretty easy and reliable to measure, and it doesn't change based on how much sleep you had the night before, or whether you ate breakfast, what the conditions of the test were, the time of day, etc.

The test-retest correlation on most IQ tests is around 0.7-0.8, whereas for height, it's almost 1.0. That means if you're measuring intelligence by a single IQ test, the correlation with genetics has a maximum of 0.7-0.8 due to noise in the test.

Studies that either explicitly correct for this, or look at averages of multiple tests taken over time show higher correlations between genetics and intelligence.

bumby2• 2 years ago

Not to make a nitpick in your point because it's a good one, but it made me wonder:

How different would the height measure be if it were standardized like IQ? E.g., how likely would someone who is in the 90% percentile in 6th grade be in the 90% percentile as an adult? From that perspective, I imagine the standardized height "re-test" correlation is a lot less than 1.0 (although it would certainly be close to that with two measures of height as an adult).

dmurray• 2 years ago

0.8 correlation with adult height for boys aged 4, according to [0]. The real study [1] is paywalled but looks legit. I'm guessing it's even higher at age 12, though it might be confounded by puberty soon after.

[0] https://www.theatlantic.com/ideas/archive/2020/02/can-you-pr...

[1] https://pubmed.ncbi.nlm.nih.gov/21767107/

Jensson• 2 years ago

whereas for height, it's almost 1.0

You grow and shrink about 1% per day, as you get compressed when you stand up and decompress when you sleep. That is about 1.5 cm, and with a human height standard deviation is about 6cm you get around 0.25 standard deviation variation when measuring the height of a single human at different times of day, or about 4 point difference if we have 15 points per standard deviation.

throwaway99172• 2 years ago

Standard deviation of human height (within a single sex) is about 7cm. If human height changes over the course of a day by 1.5cm, assuming it linearly declines over the day, that's a stddev of about 0.6cm. You also can reasonably assume that people are normally going to be measured at the doctor/researcher's office during business hours, so it's probably more like 0.4cm. The measurement error of just standing up straight or not and reading the numbers is probably more.

brachyrhynchos7• 2 years ago

Heritability doesn't provide much information about anything. Researchers working in genetics and development have moved beyond it as more sophisticated, accurate approaches have become more widely available. This paper is a good basic introduction to the concept's limitations.

Moore, D. S., & Shenk, D. (2017). The heritability fallacy. Wiley Interdisciplinary Reviews: Cognitive Science, 8(1-2), e1400.

https://wires.onlinelibrary.wiley.com/doi/full/10.1002/wcs.1...

Intelligence is not like height

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