Editing has happened to this comment since the first reply was posted to it. At first I just shared some links to scholarly articles on genetic influences on human intelligence, as I was about to go out the door to have a walk with my son the hacker as this article reached HN's front page. Now I'm back at my computer to provide some more commentary on helpful background reading for the newspaper article from today (which I learned about from a researcher on this issue). Over the years here on HN, I have often seen mistaken conclusions about "heritability" and its relationship to human intelligence from HN participants who haven't kept up with the current research literature. I keep up with the current research literature on human behavioral genetics by weekly visits during the school year to the Readings in Behavioral Genetics and Individual Differences Psychology "journal club" (graduate seminar) at the University of Minnesota.

http://www.psych.umn.edu/ugrad/pastsyllabi.html

(One or two past syllabuses of the seminar are available above. The current course page

http://www.psych.umn.edu/courses/mcgue/psy8935/

has log-in authentication to facilitate sharing current journal articles among seminar participants. The seminar also has an email list from which I learned about the New York Times article submitted here, just after today's seminar.)

An old-fashioned view of heritability estimates for human intelligence, which I see repeated frequently on HN, is that heritability constrains controllability ("malleability") of human behavioral traits. Nothing could be further from the truth.

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%20O...

is an interesting paper by some of the researchers most familiar with research on human twins, including the director of the Minnesota Study of Identical Twins Reared Apart, which includes the statement "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)."

Another interesting paper,

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%20O...

admits the disappointment of behavioral genetics researchers. Eric Turkheimer, a leading scholar in the Behavior Genetics Association, points out that the interpretation often given to "heritability" findings that they somehow measure genetic constraint on variation in a human trait is wrong.

"But back to the question: What does heritability mean? Almost everyone who has ever thought about heritability has reached a commonsense intuition about it: One way or another, heritability has to be some kind of index of how genetic a trait is. That intuition explains why so many thousands of heritability coefficients have been calculated over the years. Once the twin registries have been assembled, it’s easy and fun, like having a genoscope you can point at one trait after another to take a reading of how genetic things are. Height? Very genetic. Intelligence? Pretty genetic. Schizophrenia? That looks pretty genetic too. Personality? Yep, that too. And over multiple studies and traits the heritabilities go up and down, providing the basis for nearly infinite Talmudic revisions of the grand theories of the heritability of things, perfect grist for the wheels of social science.

"Unfortunately, that fundamental intuition is wrong. 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. An effect size of the R2 family is a standardized estimate of the proportion of the variance in one variable that is reduced when another variable is held constant statistically. In this case it is an estimate of how much the variance of a trait would be reduced if everyone were genetically identical. With a moment’s thought you can see that the answer to the question of how much variance would be reduced if everyone was genetically identical depends crucially on how genetically different everyone was in the first place."

I regret that the recent review article "The neuroscience of human intelligence differences" by Deary and Johnson and Penke (2010), relating specifically to human intelligence,

http://www.larspenke.eu/pdfs/Deary_Penke_Johnson_2010_-_Neur...

has not received more discussion on HN. "At this point, it seems unlikely that single genetic loci have major effects on normal-range intelligence. For example, a modestly sized genome-wide study of the general intelligence factor derived from ten separate test scores in the cAnTAB cognitive test battery did not find any important genome-wide single nucleotide polymorphisms or copy number variants, and did not replicate genetic variants that had previously been associated with cognitive ability[note 48]."

The review article Johnson, W. (2010). Understanding the Genetics of Intelligence: Can Height Help? Can Corn Oil?. Current Directions in Psychological Science, 19(3), 177-182

http://apsychoserver.psych.arizona.edu/JJBAReprints/PSYC621/...

is an article I submitted as a new submission on HN a little while ago. The article looks at some famous genetic experiments to show how little is explained by gene frequencies even in thoroughly studied populations defined by artificial selection.

"Together, however, the developmental natures of GCA [that is, IQ] and height, the likely influences of gene–environment correlations and interactions on their developmental processes, and the potential for genetic background and environmental circumstances to release previously unexpressed genetic variation suggest that very different combinations of genes may produce identical IQs or heights or levels of any other psychological trait. And the same genes may produce very different IQs and heights against different genetic backgrounds and in different environmental circumstances."

The brand new review article

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.

http://coglab.wjh.harvard.edu/~cfc/Chabris2012a-FalsePositiv...

is especially important for discussing social science implications of what genetic studies have shown for years now. Social scientists are still catching up with how little certainty attaches to genetic studies of human intelligence--except for the certainty, as reported in today's article, that most genetic influences on IQ are small in effect.

"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 a recognition 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. Failing to exercise such caution may hamper scientific progress by allowing for the proliferation of potentially false results, which may then influence the research agendas of scientists who do not realize 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 may lead to incorrect perceptions about the state of knowledge in the field, especially knowledge concerning genetic variants that have been described as 'genes for' traits on the basis of unintentionally inflated estimates of effect size and statistical significance."

I beg the pardon of the first participant to reply, who was annoyed by my submitting full journal citations with links to full text and relevant quotations of the article conclusions. In my own personal opinion, sometimes a Hacker News comment that links to sound research literature is more useful to participants here than expressions of personal opinion based on individual anecdotes. But reasonable minds can differ on such an issue, and I'm happy to add the commentary here that I once had a much different view of the genetic influences on human intelligence (the first popular articles I read on the subject, back in the 1970s and 1980s, were by Arthur Jensen and the late Richard Herrnstein) but I've had opportunity to learn about new research over the last twenty years, and I now know, and like to tell my friends on Hacker News, about the current consensus view that intelligence is largely a trait fixed in the genome of Homo sapiens, linked to hundreds of genes each of weak individual effect, and that most variance between one individual and another in IQ comes from poorly understood gene mutations and environmental influences that may be much more powerful than was once supposed.