from Hacker News

Intelligence is not like height

by Schiphol on 8/27/24, 12:00 PM with 161 comments

  • by blackbrokkoli on 8/27/24, 3:26 PM

    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..

  • by throwaway9917 on 8/27/24, 4:32 PM

    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.

  • by passion__desire on 8/27/24, 2:51 PM

    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.

  • by bendigedig on 8/27/24, 3:40 PM

    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?

  • by brachyrhynchos7 on 8/28/24, 12:38 PM

    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...

  • by A_D_E_P_T on 8/27/24, 2:42 PM

    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.

  • by gwervc on 8/27/24, 1:56 PM

    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.

  • by Zpalmtree on 8/27/24, 3:02 PM

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

  • by bena on 8/27/24, 2:41 PM

    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.

  • by rosmax_1337 on 8/27/24, 2:49 PM

    >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.

  • by hawkice on 8/27/24, 1:41 PM

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

  • by podgorniy on 8/27/24, 1:52 PM

  • by AmericanChopper on 8/27/24, 2:41 PM

    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.

  • by Workaccount2 on 8/27/24, 2:56 PM

    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.

  • by rowanG077 on 8/27/24, 1:50 PM

    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.

  • by stonethrowaway on 8/27/24, 2:50 PM

    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.

  • by hirvi74 on 8/27/24, 4:32 PM

    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.