(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
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
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
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:
"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
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."
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."