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tokenadult · 2012-08-31 · Original thread
Links to information about the book under review, Are We Getting Smarter?: Rising IQ in the Twenty-First Century by James R. Flynn:

http://www.cambridge.org/gb/knowledge/isbn/item6835805/?site...

http://www.amazon.com/Are-We-Getting-Smarter-Twenty-First/dp...

(The three expert reviewers shown on Amazon are all very impressive researchers on human intelligence in their own right, so their joint endorsement of Flynn's book carries a lot of weight for people like me who follow the research.)

Here is what Arthur Jensen said about Flynn back in the 1980s: "Now and then I am asked . . . who, in my opinion, are the most respectable critics of my position on the race-IQ issue? The name James R. Flynn is by far the first that comes to mind." Modgil, Sohan & Modgil, Celia (Eds.) (1987) Arthur Jensen: Concensus and Controversy New York: Falmer.

AFTER EDIT: Replying to another top-level comment:

I don't understand how anyone could not have an emotional response being told 'your IQ is x'.

People have emotional responses to most statements about themselves that they think are overall evaluations. Some of those emotional responses are more warranted than others. Devote some reading time to the best literature on IQ testing (besides the book under review in this thread, that would include Mackintosh's second edition textbook IQ and Human Intelligence

http://www.amazon.com/IQ-Human-Intelligence-Nicholas-Mackint...

and the Sternberg-Kaufman Cambridge Handbook of Intelligence,

http://www.amazon.com/Cambridge-Handbook-Intelligence-Handbo...

both recently published). Any of these books will help readers understand that IQ tests are samples of learned behavior and are not exhaustive reports on an individual's profile of developed abilities.

AFTER ANOTHER EDIT:

Discussion of heritability of IQ, a reliable indicator of how much discussants read the current scientific literature on the subject, has ensued in some other subthreads here. Heritability of IQ has nothing whatever to do with malleability (or, if you prefer this terminology, controllability) of human intelligence. That point has been made by the leading researchers on human behaviorial genetics in their recent articles that I frequently post in comments here on HN. It is a very common conceptual blunder, which should be corrected in any well edited genetics textbook, to confuse broad heritability estimates with statements about how malleable human traits are. The two concepts actually have no relationship at all. Highly heritable traits can be very malleable, and the other way around.

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 that 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.

"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."

The review article "The neuroscience of human intelligence differences" by Deary and Johnson and Penke (2010) relates specifically to human intelligence:

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

"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/...

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 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."

tokenadult · 2009-12-28 · Original thread
I've mentioned before here on HN problems with this source,

http://news.ycombinator.com/item?id=961305

which are that the source itself is notorious for lack of empirical back-up or peer review for anything submitted to it. (The Medical Hypotheses blog is associated with the journal Medical Hypotheses, edited by the same person who posted the blog post I link above, and he runs the journal, and evidently the blog as well, to post ideas of his own that cannot obtain peer-reviewed publication elsewhere.) I have read several of the articles and reviews he cites in this submitted blog post, and most have nothing to do with what he is writing about in the blog article, but are simply there to pad his reference list.

But I must, for completeness of response, mention that the book

N.J. Mackintosh, IQ and human intelligence, Oxford University Press, Oxford (1998)

http://www.amazon.com/IQ-Human-Intelligence-N-Mackintosh/dp/...

in his reference list is the best book on its subject, still amazingly current a decade after it was published (because the author is completely familiar with current research and was looking ahead to research that was still underway as he wrote his book). Even though the book is cited in a blog post that isn't supported by the book, the book itself is well worth reading.

tokenadult · 2009-04-17 · Original thread
My grand parents in their prime were just as smart as my parents, and my parents and uncles are just as smart as my cousins.

And this is one of the best empirical proofs that IQ scores are not a "measure" of how smart someone is. James Flynn discusses exactly this point of yours in several of his writings. He relates a story from Arthur Jensen about a mentally retarded man who claimed to be baseball fan, but who was very vague about the rules of baseball and didn't seem to know the names of many professional players. Yet that man had an IQ score that would relate back in time to a population average score from the era when baseball became a popular sport, widely followed in the United States.

All the Flynn effect means is that people have much more exposure to the type of puzzles in the Raven Progressive Matrix today than they did in the 1950's.

I'm very sympathetic to this statement, because I used to think that it offered the best explanation for the Flynn effect. But I am now convinced by Flynn's latest book

http://www.amazon.com/What-Intelligence-Beyond-Flynn-Effect/...

that on the one hand the gains in IQ test scores are real, and not just artifacts of familiarity with test item content (in large part because so many different kinds of tests have all shown this effect) and on the other hand that IQ has increased in society, and has been applied in the labor market and other aspects of daily life, without wisdom (Flynn's term) or rationality (Stanovich's) term increasing as generally in society.

You'd probably enjoy reading Mackintosh's book,

http://www.amazon.com/IQ-Human-Intelligence-N-Mackintosh/dp/...

by far the best introductory text on IQ testing, and Flynn's latest

http://www.amazon.com/What-Intelligence-Beyond-Flynn-Effect/...

to delight your mind by grappling with how some specialist researchers have attempted to resolve the interesting issues you bring up in your reply.

tokenadult · 2009-03-12 · Original thread
It looks like several journalists need to read the new book Intelligence and How to Get It by Richard E. Nisbett,

http://www.wwnorton.com/catalog/winter09/006505.htm

which I am reading just now. Nisbett reviews the best recent literature on IQ testing and what it means, and punches holes in the fallacious reasoning used by many advocates of a strong hereditarian view of influence on IQ.

A really good book for background reading on IQ testing and how it works is IQ and Human Intelligence by N. J. Mackintosh,

http://www.amazon.com/IQ-Human-Intelligence-N-Mackintosh/dp/...

which includes very clear explanations of how IQ tests have developed historically, how they are currently constructed and validated, and what we still don't know about human rationality despite a century of IQ testing.

tokenadult · 2009-02-20 · Original thread
Scientists have studied race and IQ. The foremost scientist who has looked at the issue is James R. Flynn, who discovered an important phenomenon, increases in IQ scores over time, that had not been noticed by psychologists in data sets that Flynn reexamined. As Mackintosh (1998, p. 104) writes about the data Flynn found: "the data are surprising, demolish some long-cherished beliefs, and raise a number of other interesting issues along the way." His book, by the way,

http://www.amazon.com/IQ-Human-Intelligence-N-Mackintosh/dp/...

is the best first book to read about IQ testing. The best second book to read about IQ testing is Flynn's latest book,

http://www.amazon.com/What-Intelligence-Beyond-Flynn-Effect/...

and the best third book on IQ testing to read, after the other two books have given you a conceptual foundation, is Keith Stanovich's latest.

http://www.amazon.com/What-Intelligence-Tests-Miss-Psycholog...

A more complete annotated bibliography

http://learninfreedom.org/iqbooks.html

lists other books, not all from the same point of view.

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