"[Some] assert than an individual's intelligence is a fixed quantity which cannot be increased. We must protest and react against this brutal pessimism."
- Alfred Binet, inventor of the original IQ test, 1909
Last week, I argued that our 21st century understanding of genetics invalidates the idea of fixed, innate abilities. Genes influence everything but determine almost nothing on their own.
What, then, is IQ? Conventional wisdom says that IQ scores reveal our native intelligence. According to this view, IQ tests are different from school grades, different from SAT scores, different from any other test you will ever take, because they somehow reveal the core, innate abilities of each person's brain: your clock speed, your RAM, your absolute limit.
That's what Stanford psychologist Lewis Terman wanted us to believe when he introduced the American version of the IQ test in 1916. (This was quite the opposite intention of the test's original co-inventor, Alfred Binet. But that's a history lesson we'll return to another time.)
What Terman had actually come up was a deceptively simple system for ranking academic progress. His Stanford-Binet tests measured many different skills, and then scored the results so that the median was always 100. If you had an IQ score of 100, it simply meant that half of the test-takers your age had done better and half had done worse.
These tests were impressively stable, which meant that, over time, most people ended up in roughly the same place in the pack. If you had tested in the 60th percentile at age 10, chances were pretty good that that you'd test close to the 60th percentile at age 12 and age 14.
But did this stability prove that the tests revealed innate intelligence?
Far from it. The reality is that students performing at the top of the class in 4th grade tend to be the same students performing at the top of the class in 12th grade, due to many factors that tend to remain stable in students' lives: family, lifestyle, resources, etc.
Being branded with a low IQ at a young age, in other words, is like being born poor. Due to family circumstances and the mechanisms of society, most people born poor will remain poor throughout their lives. But that doesn't mean anyone is *innately* poor or destined to be poor; there is always potential for any poor person to become rich.
The happy reality is that IQ scores:
A) measure developed skills, not native intelligence.
B) can change dramatically.
C) don't say anything about a person's intellectual limits.
More details below.
Coming next in this blog: Should kids know their own IQs?
____________________
AN IQ FAQ
What is IQ?
What do IQ tests
measure?
IQ tests measure current academic abilities -- not any sort of fixed, innate intelligence. More specifically, the best-known IQ battery,
"Stanford-Binet 5," measures Fluid Reasoning, Knowledge, Quantitative
Reasoning, Visual-Spatial Processing, and Working Memory. Collectively, these
skills are known as "symbolic logic." Among other things, IQ tests do
not measure creativity;[i] they
do not measure "practical intelligence" (otherwise known as
"street smarts");[ii]
and they do not measure what some psychologists call "emotional
intelligence."
Harvard's Howard
Gardner:
"The tasks featured in the IQ test are decidedly microscopic, are often unrelated to one another, and . . . are remote, in many cases, from everyday life. They rely heavily upon language and upon a person's skill in defining words, in knowing facts about the world, in finding connections (and differences) among verbal concepts . . . . Moreover, the intelligence test reveals little about an indivdual's potential for further growth."[iii]
IQ problems tend to be "clearly defined, come with all the information needed to solve them, have only a single right answer, which can be reached by only a single method, [and are] disembodied from ordinary experience . . . . Practical problems, in contrast, tend to require problem recognition and formulation . . . require information seeking, have various acceptable solutions, be embedded in and require prior everyday experience, and require motivation and personal involvement."[iv]
How are IQ scores
determined?
Can your IQ score
change over time?
If IQ scores can change over time, why do most people's IQ scores
stay reasonable stable?
So IQ scores don't
imply any sort of fixed or innate intelligence?
Quite the contrary. We
know that the abilities IQ measures are skills, and we know that people can
earn these skills. "Intelligence," Robert Sternberg has declared,
"represents a set of competencies in development." There is plenty of
evidence, for example, that schooling raises overall academic intelligence.[vii]
There is also evidence that most human beings are not reaching their cognitive
or academic potential.[viii]
Better schools and higher standards can raise the level of learning for nearly
all students.
Don't genes limit our
intelligence? Isn't intelligence "heritable?"
FOOTNOTES
[UPDATE 8/9/09: MY ORIGINAL FOOTNOTES FOR THIS POST WERE A LITTLE SLOPPY -- RIGHTLY POINTED OUT BY SEVERAL READERS. I'VE ADDED SOME PERTINENT CITATIONS AND REMOVED SOME IRRELEVANT ONES.]
[i] IQ scores do not identify the most successful and creative artists or scientists:
- Delis, D.C., Lansing, A., Houston, W.S., Wetter, S., Han, S.D., & Jacobsen, M., Holdnack, J., & Kramer, J. (2007). Creativity lost: The importance of testing higher-level executive functions in school-aged children. The Journal of Psychoeducational Assessment, 25, 29-40.- Taylor, I. A., "A
retrospective view of creativity investigation.' In Perspectives in
creativity. A. Taylor and J. W.
Getzels, eds., Aldine Publishing Co, pp. 1-36. 1975.
IQ does not distinguish the best chess players from others:
IQ scores have a weak correlation with
nonacademic intelligence and with performance in everyday tasks in other
cultures:
[iii]Howard Gardner, Frames of Mind, 1993, p. 18.
[iv] "Intelligence: Knowns and Unknowns," Report of a Task Force established by the Board of Scientific Affairs of the American Psychological Association, August 7, 1995.
Ceci, S. J. On Intelligence: A bio-ecological treatise on intellectual development. 2nd ed., Harvard University Press. 1996.
Ceci's citations:
Family environment
- Ann M. Clarke, Alan D. Clarke, Early Experience and the Life Path, Somerset, 1976.
- Dagmund Svendsen, Factors Related To Changes In IQ: A Follow-Up Study Of Former Slow Learners, Journal of Child Psychology and Psychiatry, Volume 24 Issue 3, Pages 405 - 413, 1982.
Work environment
- Melvin Kohn and Carmi Schooler, "The Reciprocal Effects of the Substantive Complexity of Work and Intellectual Flexibility: A Longitudinal Assessment" (with Carmi Schooler). 1978. American Journal of Sociology 84 (July): 24-52.
Historical environment
- Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin, 101,171-191.
Styles of parenting
- D. Baumrind, "Child care practices anteceding three patterns of preschool behavior," Genetic Psychology Monographs, 75, 43-88, 1967.
- Sanford M. Dornbusch, Philip L. Ritter, P. Herbert Leiderman, Donald F. Roberts and Michael J. Fraleigh, " The Relation of Parenting Style to Adolescent School Performance," Child Development, Vol. 58, No. 5, Special Issue on Schools and Development (Oct., 1987), pp. 1244-1257.
Individuals' IQ scores can change significantly over time:
- Harold E. Jones and Nancy Bayley, The Berkeley Growth Study, 1941 Society for Research in Child Development.
[vii]- Ceci, Stephen J., On Intelligence-- More or Less: A Bio-Ecological Treatise
on Intellectual Development, Prentice Hall, 1990.
- Richard B. Darlington, "'The Bell Curve'--solid center or abnormal deviate?." Based on a talk given by Darlington at Cornell on April 24, 1995
[viii]- Anders Ericsson, "Exceptional
memorizers: made, not born," Trends Cogn Sci. 2003 Jun;7(6):233-235.
- Bartlett, J., and Byrd, R., "Team teaching verbal, mathematics, and learning skills, Howard University Center for Academic Reinforcement, 1980.
David Shenk
...most people born poor will remain poor throughout their lives.
I wonder about that. If you assume that 20% of our population is poor, then your statement would only be true if 51% of that 20% never left that quintile. Is that true? I'd guess that there's more cycling between the income quintiles (or quartiles or what have you).
It is, in fact, true. I went a trawlin' for statistic through my highly scientific Google search.
Throughout the nineties the over-half the bottom quintile of earner remained in the bottom fifth. That doesn't take into account the significant (around 25%) of lower-middle class earners that slide back into the bottom quintile.
Overall, the picture is much the same. About forty percent of households in any quintile will remain their throughout their lives, with another 30%+ regressing.
That wouldn't be the end of the world if it were consistent throughout income brackets. You would more than likely end up where you began, but would have an equal, if lesser chance, of either moving up or down. But it's a profoundly regressive system - the poor have much more a chance of staying poor.
Its hard to believe that "About forty percent of households in any quintile will remain their throughout their lives". Take a child of middle class parents that goes off to college at 18. He has earned little to nothing when in college (and post-grad), but then will start a climb up the brackets upon graduation. Then when retiring, he settles back down the income brackets.
40% of people don't follow that normal cycle?
The only thing IQ measures is cognitive development, which is not an measure of intelligence per se, but more a measurement of capability to learn at a specific developmental phase of a young person's life.
If it is a measure of cognitive development and not some amorphous "intelligence" that few can define with certainty, then of course it changes over time: if a teenager has a fully mature adult brain—the endpoint of human cognitive development—their brain will continue to be fully mature even as they become an adult. This results in their IQ contracting to 100, or Mental Age (full adult) over Chronological Age (full adult).
I don't think that anyone would argue that IQ is a desperately poor measure of intelligence. It is, as you point out, a fair measure of learning and cognitive development, but notoriously poor at everything else.
I wish I'd read last weeks post earlier, because I agree, but disagree on a few points. No sane person would argue that genes alone determine who you are, but the nature/nurture debate is a dead, false dichotomy. Of course they interact and inform each other to create a finished, final, human being.
But to bring it to your point today - just because genes alone doesn't determine IQ, doesn't mean that genes don't provide a RANGE of IQ that the environment can help express. To contrast it to physical development - through proper intake of protein during my developmental years, through good nutrition and a smart exercise program that avoids catastophic injury, plus great training, I can become a BETTER basketball player - but I'll never be Michael Jordan. Ever. The range of capabilities that my genes can express simply don't embrace that level.
I wonder why we so easily accept the expression of unique capabilities in sport, but not in genius.
"IQ scores do not identify the most successful and creative artists or scientists"
This is an example of the faulty argument that Mr.Shenk disingenuous employs. The truth is that essentially 100% of the most successful and creative scientists come from the 5% of the population with IQ scores in the range of 130 and over. Perhaps Shenk is quibling about the possibility that some people with IQs of 145 may not be measureably more successful at science than some people with IQs of 135. This may be true. But Mr. Shenk is trying to hide from his readers the fundamental fact that essentially ALL successful scientists have IQs that are demonstrably higher than those of the vast majority of the general population.
"The happy reality is that IQ scores:
A) measure developed skills, not native intelligence."
IQ scores reflect both fluid g (skills of reasoning ability/working memory) and crystalized g (developed knowledge). Both are highly reflective of "native intelligence". So once again Mr. Shenk dissembles the facts.
"The happy reality is that IQ scores:
B) can change dramatically."
Perhaps in unusual circumstances they "can change" but as Mr. Shenk himself even admits they USUALLY TEND to be quite fixed. Once again note the disengenuousness of Shenk's argument.
"The happy reality is that IQ scores:
C) don't say anything about a person's intellectual limits."
This one is hilarious! Mr. Shenk actually wants us to believe that people with IQ scores say in the 85 to 95 range will tend to have the same intellectual limits as people with IQ scores in the 115 to 125 range; of course this is patently absurd and totally false, but perhaps there are some people--the usual left wing Boasian idealogues--who might be desperate enough to want to swallow Mr. Shenk's ridiculous assertions.
Also notice that most of the sources that Mr. Shenk cites are quite old (mostly from the 1970s and 1980s). As Judith Rich Harris (The Nurture Assumption) and Steven Pinker (The Blank Slate) have noted, only in the past couple of decades with the advent of modern behavioral genetics have most psychologists realized that their old approach at studying social class, family, and parental influences was fundamentally flawed because they did not account for the effects of genetic transmission. Mr. Shenk's views are quintessentially reflective of the outdated false Boasian mindset. Shenk seems stuck in a time warp and is simply rehashing the old views of the 1980s Stephen Jay Gould, Ned Block, Leon Kamin, Steven Rose "Not in our genes" crowd. Mr. Shenk really needs to read some modern science from the current (post 1990) literature of IQ studies and behavioral genetics before he further embarrasses himself.
It's probably true that all successful scientists have IQs significantly higher than the general population, but there is good reason to dispute that IQ can determine which individuals will be most successful.
For example, Lewis Terman used his new IQ test to identify the 1000 of the smartest children in the state of California, which inevitably became known as "Termites." They were studied throughout their lives. Many became successful lawyers, doctors, and writers, but none won the Nobel Prize, made significant discoveries in science, nor did they create any important invention unless you include Dr. Ancel Keys who invented the K-ration.
IQ scores cannot identify the most successful and creative artists or scientists because it does not measure all factors that contribute to success.
IQ I believe is partially genetic I don't agree with the the very controversial book written back in 1994 by Harvard psychologist Richard J Herrnstein, The Bell Curve, that suggest that intelligence is a predictor of many factors such as financial income, job performance,unwed pregnancy or educational level. The true controversy over this theory was when Herrnstein and his fellow author Charles Murray, wrote about the enduring racial differences in intelligence and discuss implications of those differences. It has absolutely nothing to do with race.
Speaking as a professor of psychometrics here---but one whose research area is not on intelligence---I'll throw up a few semi-random points:
-I had the benefit of seeing several lectures by James Flynn and colleagues at the Russell Sage Foundation over the last year. Very interesting stuff. I highly recommend taking a look at this work as they have been systematically examining things like: group genetic differences (nope, it seems), can IQ change, etc. This is all very much work in progress, but they've assembled an interesting set of people ranging from cognitive and developmental psychology, behavior genetics, and economics to study the problem.
-Of course the question of what IQ measures is pretty hard to pin down, but it has what validity theorists would term "criterion validity" in that it predicts many important outcomes fairly well. For many tests this is as good as the sauce gets.
-One number is rarely a good summary of an individual's capacity. However, "g" seems to be a good summary of what's common among many tests at a pretty high level of abstraction. See, e.g., Carroll, John B. Human Cognitive Abilities: A survey of factor-analytic studies. Cambridge: Cambridge University Press, 1993.
-This is a point many laypeople seem to miss: The predictive use of a given test will vary over the range of it. That's just how tests are. e.g., How useful do you think the GRE Math test is in discriminating among applicants to graduate school in math or electrical engineering or, conversely, discriminating third from fourth graders? Any variation among scores will, at those ends of ability relative to the Math GRE, be essentially noise. This is, of course, why grad programs in math often look at GRE Verbal, not for a stellar score but for a non-wretched one, and look to other information to judge mathematical ability and motivation. According to school psychologists I know, IQ tests are responsibly used more or less in this manner, to help sort out students who don't fit in the mainstream of courses (for a variety of reasons), but this would come along with other information about the individual student.
-I'll end with a paraphrase of Churchill: Standardized tests are terrible ways of sorting people, except for the other methods devised. When responsibly used (key point!), they are less terrible than the alternatives, which involve more face validity (http://en.wikipedia.org/wiki/Face_validity) but also more cost, more noise, more opportunities for biases and for gaming the system. Face validity is nice but tends to be overvalued.
For the most part, Shenk's claims seem to be cherry-picked from very old, largely outdated studies. He's not trying to explicate the meaning of IQ, but rather pushing a political agenda. For a mainstream scientific view on IQ, look here: http://www.lrainc.com/swtaboo/taboos/wsj_main.html
Thanks for all the comments so far. This is a very hot topic and I understand I'm going to ruffle some feathers. Let me make a general plea to keep this as civil as possible, and to not impugn secret motives or political agendas onto me or anyone else. There's lots of room for honest debate over what the science means, so let's try to stick to that. Those who can't show a modicum of politeness and respect deserve to be ignored rather than engaged.
A few words about my process of research and writing. I'm not a scientist, but I have written about science for a good long while now -- even won some nice awards for it. My professional philosophy is that, in a world full of complex, specialized ideas and data, there is an important place for an intermediary between the specialists themselves and the general public: Someone to ask the dumb questions and try to make sense of the complexity, to boil it down to its essence and figure out compelling ways to understand and describe it to other non-experts.
My approach is this: I begin by spending many months reading a lot of material and asking a lot of very simple questions. Over time, I begin to develop intuitions on how to summarize material, and homing in on which scientists I trust most. I then begin writing rough drafts of my articles or book chapters, and I show them to some of these scientists I most admire. Over several years of researching and writing my present book, I've been through many drafts and consulted many keen scientists to make sure I'm getting it right. By the time my book is finished, this is pretty carefully-vetted stuff.
All of which is to say that, no, I'm not foolishly out of date, and I'm not pushing some silly political agenda. I've developed a reputation for making good sense of complex science and that's what I'm doing here. These early pieces are just the beginning. It will take many months to roll out the full extent of my research and arguments.
Ok, now to JLG's charges:
"Cherry-picked." Yes, there are thousands upon thousands of relevant studies, so everyone of us has to carefully pick the ones as the most relevant for a particular point.
"Very old, largely outdated studies." There are some older studies listed above. Most of them are connected to one particular point, which is Stephen Ceci's demonstration that IQ can change dramatically as a result of a variety of factors. I don't think this point is in serious dispute, and the research cited is not the sort that gets easily dislodged by newer technology. If any particular study on the list has been widely discredited, I'm eager to know about that.
I don't think many would argue that Robert Sternberg, James Flynn, or Howard Gardner are behind the times in their understanding of intelligence and IQ, and I base my thinking on extremely current readings of their work.
Finally, on this charge of being outdated and out of the mainstream, I would point out that the single report cited by JLG was a short 1994 statement by a collection of scientists in response to The Bell Curve. Anyone who looks at that list would be hard-pressed to argue that it's truly a representative, mainstream group. By contrast, one of my sources above is a slightly more recent (1995) and much more thorough response to the same book written by a task force established by the Board of Scientific Affairs of the American Psychological Association. If there is truly any such thing as "mainstream" in science, that's it. Interested readers will note that both Stephen Ceci and Robert Sternberg are among the 11 members in that task force.
A few words now in response to Galtonian.
First, a clarification. I have struck out "or scientists" from my Footnote line: "IQ scores do not identify the most successful and creative artists or scientists." That was a very sloppy way to try to make a couple of different points at once. What I mainly meant to emphasize there was one of my early points, which I believe is simply not in dispute: that IQ tests do not measure creativity. I think Galtonian is exaggerating his point, but I'm sure it's true that most successful scientists scored well on their IQ tests as youngsters. That, of course, proves nothing about whether intelligence is innate. As I said in my own post, IQ does very successfully identify the students who are succeeding academically, and who can be predicted to continue to do so.
Second, Galtonian writes:
**IQ scores reflect both fluid g (skills of reasoning ability/working memory) and crystalized g (developed knowledge). Both are highly reflective of "native intelligence". So once again Mr. Shenk dissembles the facts.**
"G" is a whole can of worms that we can get into later, but I'll stand by my statement that IQ, along with any other intelligence or aptitude test, measures developed skills. Robert Sternberg is extremely eloquent on this point. I'll refer readers to Sternberg's “Intelligence, Competence, and Expertise.” In Handbook of Competence and Motivation, edited by A. J. Elliot and C. S. Dweck. Guilford Publications, 2005. http://bit.ly/quaHR
Third, Galtonian writes:
**Perhaps in unusual circumstances they "can change" but as Mr. Shenk himself even admits they USUALLY TEND to be quite fixed. Once again note the disengenuousness of Shenk's argument.**
Respectfully, I simply repeat my point that the fact that IQ scores tend to be stable is not proof that individuals have fixed levels of intelligence. Rather, it is evidence that, intellectually, most people tend to remain in roughly the same pecking order throughout their lives. And there are many good reasons for that having nothing to do with genetic limits.
Finally, Galtonian accuses me of being stuck in an outdated mindset and merely rehashing old views. Judith Rich Harris and Steven Pinker are cited as reflecting the latest thinking on genetics and intelligence. Respectfully, I think it's Galtonian who is one step behind. The last ten years of work in genetic expression and gene-environment interaction have demonstrated the overreach and dramatic misinterpretation of "heritability" studies. Beware of anyone trying to single out the importance of genes over environment, or environment over genes -- because their dynamic interactions are nearly impossible to separate. The main point of my work is not to point to the lack of genetic influence; rather, it is to point to the extraordinary influence we can all have on our genes and our lives.
David -
I do have to say that, until I started reading the comments, it very much seemed to me that you were pushing an agenda. Your posts are interesting, but I don't think that you make sufficiently clear that there are reasonable people who disagree. If I weren't at least somewhat familiar with the literature on this, I'd take you to be reporting well-established facts of the sort that I might use to open a conversation at work tomorrow ("Did you know...?").
Thanks for your comment, Gotchaye. I'll try to make that more apparent when appropriate. I fully intend to get into the disagreements amongst scientists, but first wanted to establish some overview pieces.
There's more potential profit for Shenk in writing a book that leans toward environmental/nurture explanations for differences in intelligence than one that leans toward hereditary explanations. The environmental/nurture angle plays into American elites' embrace of egalitarianism and regular Americans' zeal for self-improvement literature. By playing to the elites' egalitarianism, Shenk will be assured of favorable reviews in the NY Times and other media outlets. That will drive book sales, which will most likely lead to lucrative lecture gigs for Shenk.
Contrast that with what would happen if Shenk wrote a book that leaned toward hereditary explanations. Such a book would draw negative reviews from elite media outlets, and there'd be no self-improvement angle to work in lecture gigs.
The more interesting question Mr. Shenk is whether one's intelligence can change. You seem to take for granted that we have a kind of innate intelligence and are arguing that the IQ test is not a good test for it. One can then argue that we should simply change the test. A different question is can we choose to become a genius: http://www.pandalous.com/topic/can_you_choose_genius ? Perhaps there is no innate intelligence and intelligence itself can change with time.
Or perhaps you were equating IQ and intelligence and were remarking that intelligence itself can change?
"Cherry-picked." Yes, there are thousands upon thousands of relevant studies, so everyone of us has to carefully pick the ones as the most relevant for a particular point.
"Very old, largely outdated studies." There are some older studies listed above.
For someone who is familiar with intelligence research literature to some extent, reading your article and bibliography does not give the impression that you have carefully selected the most relevant studies in the field. For example, why are you completely silent on adoption and twin studies, which contain some of the most informative research on this issue?
You cannot settle a complex question such as "does the family environment affect IQ?" by citing one or two studies, about which you do not even tell anything. You must take the totality of evidence into account, and decide which view is best supported. Hopefully you will go into more detail in further posts.
I don't think many would argue that Robert Sternberg, James Flynn, or Howard Gardner are behind the times in their understanding of intelligence and IQ
I think pretty much all psychometricians would say that Howard Gardner is out of the mainstream and irrelevant in intelligence research. He himself admits nowadays that there's no evidence for his multiple intelligences hypothesis. Of course, this does not prevent tons of money being blown away through Gardner-inspired schemes in the education racket.
I would point out that the single report cited by JLG was a short 1994 statement by a collection of scientists in response to The Bell Curve. Anyone who looks at that list would be hard-pressed to argue that it's truly a representative, mainstream group.
I certainly think it's a mainstream group. It's a list of 52 full professors specializing in intelligence research. Linda Gottfredson who wrote the statement received 100 replies for her invitation to sign it. Of those 100, 52 agreed to sign it, while of the rest only seven thought that the statement did not represent the mainstream. More than a few researchers thought that the statement was correct, but declined to sign to avoid public controversy. It would be impossible to collect as long a list of similarly credentialed intelligence researchers who would disagree with the main thrust of the statement.
By contrast, one of my sources above is a slightly more recent (1995) and much more thorough response to the same book written by a task force established by the Board of Scientific Affairs of the American Psychological Association. If there is truly any such thing as "mainstream" in science, that's it.
The Task force report had fewer people behind it, and is less representative of the mainstream. Many letters by eminent psychologists were published protesting against some of its claims. Nevertheless, the conclusions in the report do not significantly differ from the Mainstream Science statement.
Sorry, Chris, if I wasn't clear. I am attempting to argue that we do not have innate intelligence, and that one's intelligence can change. The new understanding of genetics undermines the very notion of "innate." Again, this is not to say that genes don't have a very powerful influence on everything. They do. But genes are interactive with their surroundings from the moment of conception.
David, a question for you - I worry that, in disagreeing with you, I might not be disagreeing with you at all. :-) Mind clarifying a point?
I would categorically agree that environmental pressures shape native intelligence. In the major ways, such as substance addiction, neurological trauma, but also in more subtle applications, as we see things as simple as nutrition affecting gene expression.
But I still think, strongly, that this determines your intelligence within a RANGE of genetic possibilites. In other words, we can get smart to a level our genetic coding allows, but not smarter - that even in this more fluid, equitable world of intelligence, there are winners and losers. Is this something you'd necessarily disagree with?
Strawman,
You're asking all the right questions, and homing in some very good points. I want to answer them carefully and thoroughly. I'm writing this to say that I will do so soon, in this space. But it may take a few days. I'm headed to the airport soon on an overseas trip, so it may be the end of the week before I can give you and other commentors good answers.
Similar to my comment in response to your previous post, it amazes me that people have such faith in g. Perhaps folks might like to read the reference below from a professor of statistics (it's from 2007, for those who don't like older references), which shows that the method for deriving IQ from test scores will reliably yield a g factor even where sets of random numbers are used as the "scores."
http://www.cscs.umich.edu/~crshalizi/weblog/523.html
This is aside from any independent concern about what the tests in common use are actually measuring.
Besides Gould's "Mismeasure of Man," another fine book on the subject was written by a former Atlantic contributing editor, David Owen. It's entitled "None of the Above." My favorite part of the book is where Owen excerpts a section of an SAT test dealing with reading comprehension. I had no problem getting 4 of 4 answers correct, and I doubt many others reading this would have much difficulty. Oh, just one kicker - Owen did not provide the passage that the test subjects were supposed to demonstrate comprehension of in answering the questions.
So obviously, students who got perfect scores on this section of the test might have been demonstrating something quite different than the ability to comprehend the assigned passage. They (and readers of Owen's book, who don't have the passage) might be demonstrating the ability to think in ways similar to those who wrote the test questions, to the point where the correct answer just "sounds right." Now who do you think might be able to think in ways similar to the people who composed the questions? Those who had similar life and/or intellectual experiences, perhaps? In summary, the tests may be more reliable measures of "who's in with the geek crowd" than of any objectively determinable intellectual capabilities.
This is good to know. I've always wondered if environment and family really determines your intelligence and apparently it does. When I study in a certain environment or with a certain group of people, I can't focus. But when my environment and social group is changed, math doesn't feel so turbulent or essays flow like milk and honey. So just from my personal experience, I do agree.
The studies of identical twins that Pinker relies on in The Blank Slate (and the lectures he still gives on the topic) seem fairly strong evidence that genetics and the broader cultural environment are the two strongest indicators of success. Put briefly, adoptive parents seem to have little effect on the personality characteristics and life outcomes of their adopted children, while siblings raised by different parents (and especially identical twins) end up being very similar to each other.
It appears that the general economic class one grows up in (which includes peer groups), genetics, and chance are the three biggest determinants of nearly all of a person's characteristics, including "intelligence" however defined and measured. Parents have almost no effect provided that the parents you're comparing are roughly from the same economic class. While it is true that all of this is not heritable it is highly unlikely that anyone can do anything about it in the vast majority of cases.
Your reliance on economic mobility undermines your argument. As you acknowledge, most people born poor, stay poor. And most people born rich, stay rich. "Poorness" and "richness" are certainly not "innate" but just realizing that something is not innate does not make it somehow unreal or easily changeable. The myth of widespread social mobility (which is actually lesser in America than in Scandinavia, a fact that tends to surprise many Americans) is often used to support the status quo. Likewise, by giving people the hope of boundless personal growth you might make attempts to promote actual equality seem less needed.
"I'll stand by my statement that IQ, along with any other intelligence or aptitude test, measures developed skills.."
That is an extremely broad statement/claim.
IQ tests can be used to evaluate "elastic" and "inelastic" intelligence. Or crystalized and fluid, if you prefer. To dispute this, as Mr Skenk has, is incorrect. And even someone like myself, who only took a few semesters of undergraduate psychology, could tell you this.
It was actually WW1 which was responsible for the widespread use of IQ tests. Did it help the war effort? Probably not... but as a PR Tool for the field of psychology it was invaluable...
http://www.youtube.com/watch?v=h2vgtn0jbio
kathryn jones
msl
David,
An interesting paper here you may be interested in - 'Philosophy of Science that Ignores Science: Race, IQ and Heritability, Philosophy of Science 67 (2000), pp.580-602.
http://www.ln.edu.hk/philoso/staff/sesardic/getfile.php?file=POS-2000.pdf
Jud,
The Mismeasure of Man is hardly a fine book. Is an interesting book, but you must note that it doesn't correctly address Jensen's position regarding 'g' or a general intelligence factor. Here is Professor James Flynn on the Mismeasure of Man:
"Gould's book evades all of Jensen's best arguments for a genetic
component in the black-white IQ gap, by positing that they are dependent
on the concept of g as a general intelligence factor. Therefore,
Gould believes that if he can discredit g, no more need be said. This is
manifestly false. Jensen's arguments would bite no matter whether
blacks suffered from a score deficit on one or 10 or 100 factors. I attribute no intent or motive to Gould, it is just that you cannot rebut
arguments if you do not acknowledge and address them."
(Flynn "Evidence Against Rushton: The Genetic Loading of WISC-R Subtests
and the Causes of Between-Group Differences", Personality and Individual Differences 26: 373-379.)
The book got panned in a number of academic journals (a number of which a linked on wikipedia), here are some criticisms:
1. Gould's allegation that Morton had doctored his skull collection was re-investigated by John Michael. Michael found very few errors & those that were found were not in the direction Gould claimed. Michael found Gould was mistaken & that Morton's studies were conducted with integrity. Michael JS 1988. A new look at Morton's craniological research. Current Anthropology 29: 349- 54.
2. Galton (1888) observed a brain size/cognitive ability relationship. Modern MRI imaging has confirmed a positive correlation. Recently Richard Haier, at Brain Research Institute, UC Irvine College of Medicine, found that general human intelligence appears to be correlated with the volume and location of gray matter tissue in the brain.
For a summary of the neurobiological correlates with 'g' see Thompson & Gray's summary: www.loni.ucla.edu/~thompson/PDF/nrn0604-GrayThompson.pdf
Also, see this article in New Scientist dated 11 March 2009, discussing the recent twin studies on myelination & intelligence:
" By comparing brain maps of identical twins, which share the same genes, with fraternal twins, which share about half their genes, the team calculate that myelin integrity is genetically determined in many brain areas important for intelligence. This includes the corpus callosum, which integrates signals from the left and right sides of the body, and the parietal lobes, responsible for visual and spatial reasoning and logic (see above). Myelin quality in these areas was also correlated with scores on tests of abstract reasoning and overall intelligence (The Journal of Neuroscience, vol 29, p 2212).
Just because intelligence is strongly genetic, that doesn't mean it cannot be improved. "It's just the opposite," says Richard Haier, of the University of California, Irvine, who works with Thompson. "If it's genetic, it's biochemical, and we have all kinds of ways of influencing biochemistry."
http://www.newscientist.com/article/mg20126993.300-highspeed-brains-are-in-the-genes.html
This recent study by Thompson is also discussed here in MIT Tech Review:
"The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited."
http://www.technologyreview.com/biomedicine/22333/page2/
3. Gould's criticism of factor analysis (and 'g') is flawed: see John Carroll's review Intelligence 21, 121-134 1995 and also Jensen Contemporary Education Review Summer 1982, Volume 1, Number 2, pp. 121- 135.
David J. Bartholomew, from London School of Economics, who has written a textbook on factor analysis, also explains in "Measuring Intelligence: Facts and Fallacies" explains where Gould goes wrong in this area.
4. Gould suggests that Jews tested poorly in the 1920's & this lead to the Immigration Act 1924. Both are incorrect.
5. The idea that Jews tested poorly is actually based on a misrepresentation of a paper authored by Henry Goddard in 1917. Goddard gave IQ tests to people suspected of being mentally handicapped. He found the tests identified a number of such people from various immigrant groups, including Ashkenazi Jews. Leon Kamin in 1974 reported that Goddard had found Jews had low IQ scores. However, Goddard never found that Jews or other groups as a general population had low scores. There is other information that contradicts the idea that Jews did poorly on IQ tests around this time. In 1900, in London, Jews took a disproportionate number of academic prizes in spite of their poverty (C Russell & H.S. Lewis 'The Jew in London' Harper Collins 1900). Also, note that by 1922 Jewish students made up more than a fifth of Harvard undergraduates & the Ivy League was already instituting policies aimed at limiting Jewish admissions (the infamous 'Jewish quotas'). Also, a 1920's a survey of IQ scores in three London schools with mixed Jewish & non-Jewish student bodies - one prosperous, one poor and one very poor - showed that Jewish students, on average, had higher IQ's than their schoolmates in each of the groups (A Hughes 1928).
- see also: G. Cochran, J. Hardy, H. Harpending, Natural History of Ashkenazi Intelligence, Journal of Biosocial Science 38 (5), pp. 659-693 (2006).
6. The other misconception is that this contributed to the 1924 Immigration Act. However, Herrnstein & Snyderman found this was not the case (Intelligence Tests and the Immigration Act of 1924' American Psychologist 38, September 1983).
7. Although it was claimed Cyril Burt made up data for his twin studies, subsequent investigations have cast doubt on this. See the book Cyril Burt 'Fraud or Framed', edited by Nick Mackintosh former Chair of Psychology at the University of Cambridge.
8. Burt's findings regarding hereditary appear to be very consistent with subsequent twin studies.
"I don't think many would argue that Robert Sternberg, James Flynn, or Howard Gardner are behind the times in their understanding of intelligence and IQ, and I base my thinking on extremely current readings of their work."
David, it seems that you are essentially repeating what Malcolm Gladwell has done - identify the most publicly palatable research and write a book about it. Have you read any papers by Arthur Jensen?
What about Linda Gottfredson, who has been quite critical of the lack of data to back up Gardner's theory. Gottfredson's papers are easily located here:
http://www.udel.edu/educ/gottfredson/reprints/index.html
There is also some fascinating research on the connection between intelligence, academic attainment and health outcomes by Professor Ian Deary from University of Edinburgh.
Also, there is recent work by Paul Thompson at UCLA on genetic influences on brain structure. Factors like cortical thickness and myelination quality which affects processing speed appear quite important. For instance, Einstein had a larger than average ratio of glial cells which affects myelination. Here is a link to a recent study by Thompson where he studied fraternal and identical twins:
"Thompson and his colleagues took DTI scans of 92 pairs of fraternal and identical twins. They found a strong correlation between the integrity of the white matter and performance on a standard IQ test. "Going forward, we are certainly going to think of white matter structure as an important contributor of intelligence," says Van Wedeen, a neuroscientist at Massachusetts General Hospital in Boston, who was also not involved in the research. "It also changes how you think about what IQ is measuring," says Wedeen. The research was published last month in the Journal of Neuroscience...
The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited."
http://www.technologyreview.com/biomedicine/22333/