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 An excellent introduction to intelligence and case against strong hereditarianism February 10, 2009
Carl M. Shulman
67 out of 76 found this review helpful
Nisbett's latest book serves several purposes. On one level, he is arguing with his fellow IQ researchers that "schools and culture matter" more than the field suspected (e.g. a 1987 survey by Stanley and Rothman found high estimates of individual heritability and plurality support for the view that both genetic differences and environment played a role in American IQ gaps). Nisbett marshals a persuasive case, and while his thesis is forcefully stated he is scrupulous in pointing out contrary arguments and evidence. Occasionally the main text seemed to overstate a point, but in the vast majority of such cases a turn to the notes section or appendices revealed that the complications had been mentioned there (with a few exceptions related to the views of hereditarians on dysgenics and the causes of low IQ in Africa), and the book could serve as a good introduction to the field for laypeople.
Another major element of the book is a call for bringing scientific rigor to education. Rigorous controlled experiments, research that takes our knowledge of IQ into account, genetics-aware studies such as Eric Turkheimer's (which measure environmental effects on phenomena such as substance abuse using twins to control for genetic effects), and clear thinking have the potential to greatly improve the effectiveness and cost-effectiveness of education and improve cognition. Fear of hereditarian views and associations with racism often hinder educational policymakers from taking our scientific knowledge of IQ into account, with negative effects on educational quality, and we may hope that this text will help to diminish that stigma and help to drive further improvements in cognitive ability.
At a higher level, the book is in some ways an ode to the randomized experiment, taking a strong stand against regressions that are helpless to identify causality and easily manipulable by motivated researchers. A reader gets the sense of a smart and honest empirical scientist who is eager to have questions resolved by hard evidence, and ready to change his mind in accord with those experiments, even when he comes to the table with strongly held initial views on a controversial topic of policy importance. This is something we need to see more of in scientific and policy debates and I give this book my strong recommendation. If you enjoy this book, I would suggest a follow-up with James Flynn's "What is Intelligence?" and Arthur Jensen's "The G-factor."
I will discuss the individual chapters below:
Chapter 1 provides a brief introductory account of IQ, and its importance for life outcomes, while mentioning other important traits such as motivation and self-control. It is quite satisfactory and puts IQ in context, without diminishing its role or getting embroiled in terminological disputes over the description of other abilities or discussion of their measurement.
Chapter 2 attempts to place the high heritability of IQ scores among middle class families (as much as 70-80% of variation in IQ can be explained by genetics within that group) into context, noting that adoptive households tend to be relatively good environments for children (confirmed by across-the-board boosts in IQ for adopted children, although these generally fade with time), and this consistently high quality means that variation in genetics plays a greater relative role. He also cites Turkheimer's research finding lower heritability of IQ among famlies with lower socioeconomic status.
Chapter 3 reviews the literature on the IQ-increasing effects of education, drawing on natural experiments of differential phase-in of education, or disruption due to strikes and disturbances. It is undeniable that schooling increases IQ relative to its absence, and these gains can be lasting. A discussion of the Flynn Effect, the secular increase in IQ scores over the last half century and more, follows James Flynn's "What is Intelligence?" and emphasizes that the particular IQ subtest scores that have increased cover skills that modern education and entertainment place much more emphasis on than in the past. One particularly devastating application is to the critique of 'culture-fair' nonverbal tests such as Raven's Progressive Matrices. These tests, which require subjects to identify patterns in abstract shapes, have shown extremely high culturally-driven increases over time, but they are also used extensively by researchers such as Lynn and Vanhanen to estimate developing country IQ levels. This application is typically defended along the lines that the within-country correlations of life outcomes and Raven scores are strong, but such correlations would not be disrupted by an across-the-board change such as the Flynn Effect (and have not been disrupted in rich countries) or its absence, and these tests are clearly 'culture-unfair.'
Chapter 4 covers the state of educational research, and is one of the best parts of the book, although the findings have been discussed elsewhere. Nisbett urges a scientific approach to educational research and policy, relying on randomized experiments, and critiques the ludicrous excesses of schools of education that reject the experimental method. Reviewing the research on funding levels, teacher quality, and class size, he rejects common myths and focuses on evidence. For instance, teacher quality matters quite a lot for student achievement, but it is not strongly related to seniority after the first two years or to Master's degrees, the criteria according to which most union contracts allocate raises. Instead, direct measurements of student improvement are the best predictors of future performance. Federal policy, the D.C. school system under Mayor Fenty and Michelle Rhee, and the Gates Foundation are all moving in this direction, and I hope that the new wave of experimentally-informed educational practices is able to displace ineffective policies and their political support.
Chapter 5 reviews the large differences in parenting between social classes, e.g. the number of words upper middle class parents speak to their children is much greater than the number spoken by lower class parents, and upper class parents are more encouraging of thought by their children. These results are confounded by genetics, which may simultaneously affect parenting style and child behavior, but they are very interesting nonetheless, and the gains of children raised in adoptive households and some parenting interventions suggest that they do have some causal importance. Importantly, such parenting practices do not change instantly when offspring rise into the middle class, which may be important in explaining the poor test performance of the children of first-generation middle class families of all groups.
Chapter 6 addresses the IQ gap between blacks and whites, arguing for a genetic contribution of zero, and must be read in tandem with Appendix 2, which provides more detailed arguments. Nisbett discusses a substantial partial closing of the IQ gap among children over the last 50 years, and corresponding improvements in school achievement. These gains weaken among teenagers and further among adults, but even on their own they represent a major advance, and suggest that efforts like KIPP could go much further.
Nisbett places a particular focus on evidence from European admixture in African-Americans (on average about 20%). For instance, he notes that skin color, facial features, and blood groups show only tiny correlations with IQ. These arguments turn out not to work because of the sample sizes and the genetics of those traits, but a similar analysis with DNA ancestry testing should now be feasible. More persuasively, Nisbett reviews the mixed evidence from studies of adopted children with one or two black parents. Each of the several studies has confounding effects at play, such as lack of parental IQ information, but collectively they leave it in doubt whether biracial children really do show an advantage over children with two black parents, and pose a challenge for hereditarians selectively focusing on the one (of three) major study showing an advantage for biracial children.
Nisbett presents a number of other lines of argument, with one particularly telling point being the fact that that among African-Americans women predominate in the upper IQ echelons, while among whites the pattern is reversed, and I expect that they will indeed shift scientific opinion towards a lower estimate of the importance of genetics. At the least, we should be confident that environmental interventions, provided that they are validated by randomized trials, can further increase black IQ and that fatalism is mistaken.
Chapter 7 discusses IQ-boosting programs such as the Perry Preschool Program, the Milwaukee Project, and the Abecedarian Program. Overall, there are many disappointing results and some gems, but those gems have shown in randomized experiments that they produce benefits that exceed their costs. IQ gains are often temporary, but a gain that lasts for several years after a program enables increased academic achievement and learning during that time (with lasting benefits), and some gains are significantly more long-lived. More importantly, life outcomes such as employment, use of public assistance, and crime can be dramatically affected. The Obama administration has promised to and is likely to roll out extensive programs along these lines, but the key to success will be rigorous and continuous evaluations that are taken into account in expanding some programs and paring back others.
Chapter 8 covers the high achievement of people of Northeast Asian descent (Japanese, Chinese, Korean). Nisbett correctly emphasizes that regardless of whether or not there is a moderate IQ advantage for these populations, their educational achievements are greatly superior to what would be predicted from IQ alone. Increased conscientiousness due to cultural values of duty to family, a belief in the importance of hard work relative to innate ability, and a tradition of education are cited as explanations for the difference in motivation. One point I would raise here is that cultural environment may also have selected for genetic variations affecting personality. Indeed, a polymorphism at the DRD4 locus associated with ADHD and impulsivity is found in very different regional proportions (it is high in countries recently populated by immigrants, for example) has been found to be extremely scarce in China. A unified stable state living very close to Malthusian margins for many centuries does seem potentially conducive to the evolution of increased conscientiousness among subsistence farmers.
Chapter 9 discusses the high IQ and intellectual achievements of Ashkenazi Jews. With respect to the latter, Nisbett rightly notes that there is strong variation in regional intellectual achievement independently of IQ, e.g. the lack of scientific advance from Texans (even limited to non-Hispanic whites). He discusses various accounts of Ashkenazi intelligence, most importantly the evolutionary biology approach of Cochran, Hardy, and Harpending. Those researchers use statistical analysis to argue that the clustering of Ashkenazi diseases that are linked to increased dendrite growth, myelin in the brain, or increased IQ is vanishingly unlikely unless the Ashkenazim were subject to recent selection, likely due to the extended period when the majority were in finance or related occupations and financial success was strongly associated with numbers of surviving children.
Nisbett thinks that this theory is plausible, although its prediction of increased IQ in heterozygotes for the recessive diseases has not yet been tested, but argues correctly that Jewish achievement exceeds what would be predicted from IQ alone. However, selection for success in moneylending and professional occupations would almost certainly select for self-control and low time preference as well as IQ, so evolutionary considerations may explain more of Ashkenazi success than the chapter suggests. Further genetic differences would support cultural differences: if a high fraction of one's relatives and peers are more intelligent and self-disciplined, that will foster a culture of intellectualism and achievement that will multiply the initial difference. Regardless of the exact causes, they should be studied to determine how to duplicate them elsewhere (whether through education or pharmacology/gene therapy).
Chapter 10 concludes the book with discussion of what parents can do to help cultivate their children's intelligence in a handy presentation that pays attention to relevant caveats and limits of our knowledge. A brief epilogue summarize the main claims of the book and pronounces strong hereditarianism overthrown.
Beyond Fatalism about Intelligence February 4, 2009
Historied (UK and USA)
24 out of 27 found this review helpful
I really enjoyed this book, having previously been stimulated by the author's Geography of Thought. So much of the recent writing about intelligence has been marred by the sloppy use of research, especially in the area of the heritability of intelligence. Nisbett has good appendices explaining the relevant stats and also taking to task the somewhat infamous 'Bell Curve' that I still hear talked about by lay people to this field as gospel. I think he respects those he disagrees with such as Steven Pinker and pays them the respect of not misrepresenting them.
Richard Nisbett's inventive cover says it all: DNA (inherited characteristics) as a ladder to build intelligence on and beyond, rather than as a cage to limit intelligence. With this end in mind, the book includes some marvellously balanced accounts of relevant research and is extremely helpful in overturning the more simplistic interpretations. Nisbett is course not arguing that intelligence is not significantly inherited, just that environmental factors are equally important and recently neglected in much research commentary and policy advocacy. And also environmental factors are what we can strongly influence.
Advocates of the high heritability of intelligence are pessimists and the massive increase in intelligence of the last 50 years across most countries studied by Flynn et al. as Nisbett shows puts a major set of counter data in the way of their perspective. Nisbett is also adept at puncturing the racist use of differential IQ scores between white and black population. This differential is falling dramatically just as average scores also increase.
Among the most interesting insights he provides are those into the identical twins reared apart data. He shows that at the nub of so much misinterpretation is neglect of the simple idea that if two variables determine something and one of the variables is kept roughly stable, then all of the variation is caused by one variable. So if data on identical twins reared apart show 80% of the variation in their intelligence is inherited, you do need to know how varied their backgrounds are. And the answer is probably not very varied. Indeed Nisbett goes on to indicate studies that show upper middle class children having perhaps 70% inherited intelligence, because how they are all raised in very driven, standardized ways, and the top schools are all doing similar things. While children in the lowest part of society have very low heritability of IQ because their environments are so massively varied.
Nisbett has some interesting things to say about cross cultural issues in IQ. But I think his most interesting insight, is that so many Americans now believe that maths talent is inherited, whereas many Asian immigrants to America believe it is the result of damned hard work. This is one of those paradoxes that the most conservative of Americans have embraced inherited ability (Bell Curve etc.) as a way to fend off social engineering via education, while the folk who are overwhelming the gifted programs of America, don't believe this and they seem to be right. There is little IQ difference: the Asian kids just work hard at maths!
For those who come to this book with strong preference towards the high heritability of intelligence, I would simply ask that you open mindedly consider the data and read the sources Nisbett quotes. We need your support to get moving on helping make society smarter. Nisbett has plenty of ideas about further research to really test what works: above all by applying experimental method and having randomly selected control groups for any program to test its real efficacy.
Intelligence is getable February 27, 2009
Coert Visser (Driebergen Netherlands)
4 out of 6 found this review helpful
Did you read the 1996 book Bell Curve: Intelligence and Class Structure in American Life (A Free Press Paperbacks Book) and did it make you feel uneasy because you did not (want to) agree with its conclusions but did not exactly know how to refute them? Among its conclusions were (loosely formulated)
1) that intelligence is highly important in many areas of life,
2) that differences in intelligence are largely responsible for societal stratification,
3) that differences in intelligence are largely heritable, and
4) that intelligence gaps between (racial) groups are hard to close (if that is possible at all).
If you felt (feel) uneasy about these conclusions read this book by psychologist Dick Nisbett. You will probably like this book because it will provide answers to your questions. Not in a vague way but in a very specific, well reasoned and research based way. Here are some conclusions from the book:
1) There is no fixed value for the heritability of intelligence. If the environment is very favorable to the growth of development of intelligence, the heritability of intelligence is fairly high (maybe up to 70%. If however the environment is highly variable -differing greatly between individual families- then the environment is going play the major role in differences in intelligences between individuals (as is the case with the poor).
2) Aside from the degree to which heritability is important for one group or another in the population, heritable places no limits whatsoever on modifiability -for anybody,
3) Intelligence is developable and schools can make children smarter, for instance by using computer-assisted teaching and certain types of cooperative learning. 3) Genes play no role at all in race differences in IQ, environment differences do.
4) Believing that intelligence is under your control is a great start of developing intelligence,
5) Certain habits and values in cultures can be highly beneficial for learning and developing intelligence,
6) Parents can do a lot to increase the intelligence and academic achievement of children (both biological and didactic factors matter.
This book is great. [...]Let's hope it will inspire many parents, educators, policymakers and scientists. It just might ...
Even handed summary of important research February 28, 2009
Timothy J. Bartik (Kalamazoo, MI USA)
4 out of 6 found this review helpful
Nisbett's book addresses two audiences with this book, in a manner that is generally fair-minded and hence persausive.
First, he addresses an audience interested in how culture affects "intelligence", versus genetics. He presents evidence for why culture and other environmental influences have larger effects on intelligence than genetic factors. This discussion touches on some very "hot button" issues, such as differences across ethnic groups in achievement.
Second, he addresses an audience interested in how schools can most effectively increase students' "intelligence" or academic achievement. He reviews evidence on the effectiveness of various academic interventions, such as high-quality preschool and child care, academic programs such as Reading Recovery, whole school reforms such as the KIPP program, and class size reduction. Particularly noteworthy and unusual are his discussions of some educational interventions promoted by social psychologists, such as efforts to persuade students that effort can significantly increase intellectual achievement.
The tone is consistently even-handed. Nisbett frequently discusses arguments and evidence against his positions. With respect to Nisbett's discussion of the influence of culture on intelligence, I do not know the scientific literature sufficiently to judge the accuracy of his summary. However, based on my knowledge of the research on early childhood education and education, I believe Nisbett's summary of this research is generally accurate. He provides the reader with a good guide to some interesting findings in the education literature.
school board member July 21, 2009
A. Follower (Sonoma, CA)
1 out of 4 found this review helpful
This book so impressed me that I bought it for the board members, all the principals, the superintendent, and the Curriculum Director. I read about it in two columns by Nicholas Kristof, who took up Darfur's cause a year ahead of everyone else. Gladwell's "Outliers" uses the research cited by Nisbett. Same for "Whatever it Takes", about Geoffrey Canada and his Harlem Childrens' Project. So this book is like the well from which much new water is flowing. It is so full of research as to be the most useful tool in any effort to reform public education. Most of the 'new' books are like sermons: someone comes up with a cool idea and then backs it up with lots of anecdotes (see "Whatever it Takes"). You won't be able to read this without changing your views about what public school can be... unless you go in of the same mindset. And this book provides the rock solid research, not opinions. Oops - there are opinions, but Dr. Nisbett tells you when that's the case.
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