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I read this article earlier when it was first published. I have also read most of the prior literature cited in the article's references. A review article, by s

I read this article earlier when it was first published. I have also read most of the prior literature cited in the article's references. A review article, by some of the same authors the article kindly submitted here cites, gets at the nub of the issue. "Moreover, even highly heritable traits can be strongly manipulated by the environment, so heritability has little if anything to do with controllability. For example, height is on the order of 90% heritable, yet North and South Koreans, who come from the same genetic background, presently differ in average height by a full 6 inches (Pak, 2004; Schwekendiek, 2008)."[1] It is completely unremarkable that chimpanzee studies show "heritability" for what counts as intelligence (by this study's model) among chimpanzees. In general, for any trait, closely related individuals show a stronger resemblance than less closely related individuals, and that is what "heritability" means, nothing more. Eric Turkheimer (one of the authors cited in the article submitted here, and a co-author of the review article I have just quoted and cited) declared as the "first law of behavior genetics" that all human behavioral characteristics are heritable, and that is very close to being literally true. But he also writes, in a later commentary article, "Heritability isn't an index of how genetic a trait is. A great deal of time has been wasted in the effort of measuring the heritability of traits in the false expectation that somehow the genetic nature of psychological phenomena would be revealed. There are many reasons for making this strong statement, but the most important of them harkens back to the description of heritability as an effect size."[2] The chimp research is interesting, and I suppose other researchers will try to replicate or refine it, but it still leaves us a long way from understanding the genetics of human intelligence. Human intelligence is indubitably influenced by hundreds of genes, each of small effect size, and many with unknown pleiotropic effects. We are so far nowhere near understanding what genes do to influence human intelligence. "At the time most of the results we attempted to replicate were obtained, candidate-gene studies of complex traits were commonplace in medical genetics research. Such studies are now rarely published in leading journals. Our results add IQ to the list of phenotypes that must be approached with great caution when considering published molecular genetic associations. In our view, excitement over the value of behavioral and molecular genetic studies in the social sciences should be tempered—as it has been in the medical sciences—by an appreciation that, for complex phenotypes, individual common genetic variants of the sort assayed by SNP microarrays are likely to have very small effects. Associations of candidate genes with psychological traits and other traits studied in the social sciences should be viewed as tentative until they have been replicated in multiple large samples. Doing otherwise may hamper scientific progress by proliferating potentially false results, which may then influence the research agendas of scientists who do not appreciate that the associations they take as a starting point for their efforts may not be real. And the dissemination of false results to the public risks creating an incorrect perception about the state of knowledge in the field, especially the existence of genes described as being 'for' traits on the basis of unintentionally inflated estimates of effect size and statistical significance."[3] Meanwhile, we know that even monozygotic ("identical") twins can be discordant for IQ or for any other human behavioral trait (this observation is also called a "law of behavior genetics"), so the one thing we can be sure of is that something other than genes matters for the expression of absolutely every trait that a human being can have. This being well known, those of us who have already received our shuffle of genes may as well devote time, money, and effort to finding out what environmental factors may help us engage in problem-solving about important human problems. [1] Johnson, Wendy; Turkheimer, Eric; Gottesman, Irving I.; Bouchard Jr., Thomas (2009). Beyond Heritability: Twin Studies in Behavioral Research. Current Directions in Psychological Science, 18, 4, 217-220 http://people.virginia.edu/~ent3c/papers2/Articles%20for%20Online%20CV/Johnson%20(2009).pdf http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O... [2] Turkheimer, E. (2008, Spring). A better way to use twins for developmental research. LIFE Newsletter, 2, 1-5. http://people.virginia.edu/~ent3c/papers2/Articles%20for%20Online%20CV/Turkheimer%20(2008).pdf http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O... [3] Chabris, C. F., Hebert, B. M., Benjamin, D. J., Beauchamp, J., Cesarini, D., van der Loos, M., ... & Laibson, D. (2012). Most reported genetic associations with general intelligence are probably false positives. Psychological science, 23(11), 1314-1323. DOI: 10.1177/0956797611435528 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498585/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498585/ http://dash.harvard.edu/bitstream/handle/1/9938142/Most_Reported_Genetic.pdf?sequence=1 http://dash.harvard.edu/bitstream/handle/1/9938142/Most_Repo...

gwern 12y ago
> But he also writes, in a later commentary article, "Heritability isn't an index of how genetic a trait is. A great deal of time has been wasted in the effort of measuring the heritability of traits in the false expectation that somehow the genetic nature of psychological phenomena would be revealed. There are many reasons for making this strong statement, but the most important of them harkens back to the description of heritability as an effect size."[2] It is true that heritability does not logically imply immalleabillity. But, leaving aside the many cases of untreatable or fatal genetic diseases as possibly too easy, I am struck by how often heritability does turn out to be about traits which are difficult or impossible to change; we are familiar with the case of intelligence, of course, but it shows up almost anywhere heritability does. Consider the case of politics: political affiliation is highly stable over lifetimes, impenetrable to argumentation, people will tie themselves in knots to preserve their beliefs (consider the people who argue that WMDs were successfully found in Iraq), increasingly linked to fundamental differences in cognition (see https://news.ycombinator.com/item?id=8512400 https://news.ycombinator.com/item?id=8512400 ) - and political attitudes are highly heritable (https://news.ycombinator.com/item?id=8512399 https://news.ycombinator.com/item?id=8512399 / https://news.ycombinator.com/item?id=8504593 https://news.ycombinator.com/item?id=8504593). This pattern pops up over and over again: if a study calculates the heritability of a number of traits, the traits which are high on heritability and low on shared environment will strike one as things which are hard to change. If you don't like attitudes or politics or intelligence, consider personality like the Big Five construct: OCEAN are all highly heritable (~40% avg), and yet, largely unchangeable. Do you know any way to increase Conscientiousness aside from dopaminergic stimulants? I don't. Do you know any way to increase Openness besides possibly psychedelics? I don't. And so on. > Associations of candidate genes with psychological traits and other traits studied in the social sciences should be viewed as tentative until they have been replicated in multiple large samples. Doing otherwise may hamper scientific progress by proliferating potentially false results, which may then influence the research agendas of scientists who do not appreciate that the associations they take as a starting point for their efforts may not be real. And the dissemination of false results to the public risks creating an incorrect perception about the state of knowledge in the field, especially the existence of genes described as being 'for' traits on the basis of unintentionally inflated estimates of effect size and statistical significance."[3] It would be nice if, in your constant citation of Chabris, you would incorporate any of the information I've given you in my other replies to you.

gwern 12y ago

> But he also writes, in a later commentary article, "Heritability isn't an index of how genetic a trait is. A great deal of time has been wasted in the effort of measuring the heritability of traits in the false expectation that somehow the genetic nature of psychological phenomena would be revealed. There are many reasons for making this strong statement, but the most important of them harkens back to the description of heritability as an effect size."[2] It is true that heritability does not logically imply immalleabillity. But, leaving aside the many cases of untreatable or fatal genetic diseases as possibly too easy, I am struck by how often heritability does turn out to be about traits which are difficult or impossible to change; we are familiar with the case of intelligence, of course, but it shows up almost anywhere heritability does. Consider the case of politics: political affiliation is highly stable over lifetimes, impenetrable to argumentation, people will tie themselves in knots to preserve their beliefs (consider the people who argue that WMDs were successfully found in Iraq), increasingly linked to fundamental differences in cognition (see https://news.ycombinator.com/item?id=8512400 https://news.ycombinator.com/item?id=8512400 ) - and political attitudes are highly heritable (https://news.ycombinator.com/item?id=8512399 https://news.ycombinator.com/item?id=8512399 / https://news.ycombinator.com/item?id=8504593 https://news.ycombinator.com/item?id=8504593). This pattern pops up over and over again: if a study calculates the heritability of a number of traits, the traits which are high on heritability and low on shared environment will strike one as things which are hard to change. If you don't like attitudes or politics or intelligence, consider personality like the Big Five construct: OCEAN are all highly heritable (~40% avg), and yet, largely unchangeable. Do you know any way to increase Conscientiousness aside from dopaminergic stimulants? I don't. Do you know any way to increase Openness besides possibly psychedelics? I don't. And so on. > Associations of candidate genes with psychological traits and other traits studied in the social sciences should be viewed as tentative until they have been replicated in multiple large samples. Doing otherwise may hamper scientific progress by proliferating potentially false results, which may then influence the research agendas of scientists who do not appreciate that the associations they take as a starting point for their efforts may not be real. And the dissemination of false results to the public risks creating an incorrect perception about the state of knowledge in the field, especially the existence of genes described as being 'for' traits on the basis of unintentionally inflated estimates of effect size and statistical significance."[3] It would be nice if, in your constant citation of Chabris, you would incorporate any of the information I've given you in my other replies to you.