We had almost this exact same discussion a month ago. Firstly, you quote only from Flynn and not from any scientist holding an opposing viewpoint (e.g. Arthur Jensen). Although Flynn is a good scientist, I don't think that it is good to rely just on the studies of one political scientists and activist – he is author of “How to Defend Humane Ideals: Substitutes for Objectivity” after all).
There are numerous studies that also show that the general intelligence factor is due to physiological effects (e.g. size of different areas of the brain, etc...). How do you explain that?
There is a theory on why when people are trained in a task they do better – it turns out that the amount of “general intelligence” used is less. There are also studies that show this effect with PET scans of the brain:
> Thus, the largest GMR decreases with practice were found on subtests with the highest
g loadings. Jensen noted this finding was consistent with what he termed the conservation of g.
Namely, with practice and training, tasks become more automatized and require less g.
(from Haier [1])
There is a recent study (2008, te Nijenhuis ,van Vianen , van der Flier [2]) that shows that the increase in RSPM and other scores is because of training and is not an increase in the overall general intelligence [2] (the studies that you cited is all 8 years or older). Incidentally this study cites two of the Flynn papers that you cited (Massive IQ Gains in 14 Nations: What IQ Tests Really Measure, IQ Gains, WISC Subtests and Fluid g: g Theory and the Relevance of Spearman's Hypothesis to Race).
The idea that Flynn proposes (i.e. that general intelligence is increased over time is dismissed). Here is a full quote of the abstract of the paper (if you need the full paper and do not have access to it, msg. me and I will email it for you):
IQ scores provide the best general predictor of success in education, job training, and work. However, there are many ways in which IQ scores can be increased, for instance by means of retesting or participation in learning potential training programs. What is the nature of these score gains? Jensen [Jensen, A.R. (1998a). The g factor: The science of mental ability. London: Praeger] argued that the effects of cognitive interventions on abilities can be explained in terms of Carroll's three-stratum hierarchical factor model. We tested his hypothesis using test–retest data from various Dutch, British, and American IQ test batteries combined into a meta-analysis and learning potential data from South Africa using Raven's Progressive Matrices. The meta-analysis of 64 test–retest studies using IQ batteries (total N = 26,990) yielded a correlation between g loadings and score gains of − 1.00, meaning there is no g saturation in score gains. The learning potential study showed that: (1) the correlation between score gains and the g loadedness of item scores is − .39, (2) the g loadedness of item scores decreases after a mediated intervention training, and (3) low-g participants increased their scores more than high-g participants. So, our results support Jensen's hypothesis. The generalizability of test scores resides predominantly in the g component, while the test-specific ability component and the narrow ability component are virtually non-generalizable. As the score gains are not related to g, the generalizable g component decreases and, as it is not unlikely that the training itself is not g-loaded, it is easy to understand why the score gains did not generalize to scores on other cognitive tests and to g-loaded external criteria.
So what we have for the immutability of general intelligence is a theory, intelligence test results confirming the theory and PET scans of the brain showing this effect.
[1] Richard J. Haier, Ph.D., Positron Emission Tomography Studies of Intelligence: From Psychometrics to Neurobiology
[2] Jan te Nijenhuis , Annelies E.M. van Vianen , Henk van der Flier, Score gains on g-loaded tests: No g
PS: This reply is a little long so sorry for that.
I've read more of what Haier has to say since his name last came up in an HN thread. I especially like this quote:
"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.'"
The all kinds of ways to influence biochemistry include influences that are not themselves biochemical. Things that people DO can cause biochemical changes in their brains. (Sleep deprivation is well known to do that, for example, as are activities that bring about good mood.) Very likely engaging in challenging education brings about biochemical changes that result in changes in IQ.
you quote only from Flynn and not from any scientist holding an opposing viewpoint (e.g. Arthur Jensen)
First of all, let me say very forthrightly that maybe mainstream journalism operates on an equal-time principle, but science manifestly does not. It actually makes no difference at all who says anything in science, because it should be examination of the data that leads to a conclusion, not examination of a scientist's reputation. But since you asked me to quote Arthur Jensen, I will be glad to:
"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.
> '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.'"
There is good evidence that several compounds can increase intelligence (albeit temporary in most cases). A good example is several stimulants. The best way would probably be to alter the genetics directly. This however does not take away the fact that it is still innate and most people are not likely to see their intelligence changed.
> Very likely engaging in challenging education brings about biochemical changes that result in changes in IQ.
Is there any evidence that this is the case (i.e. research studies)? This may happen – but I have not seen any documented evidence of that this is the case.
If this was the case, children adopted at birth in middle class families would have general intelligence factors matching their step-parents (this is not the case). Also, the general intelligence factor would be changed with learning – but there has not been any evidence that this is the case.
> First of all, let me say very forthrightly that maybe mainstream journalism operates on an equal-time principle, but science manifestly does not.
That is true. Views of science with which the majority of scientists agree is generally represented as the opposite in the public press. A good reason for that is in the public sphere the “ought to” become “is” and scientists reinforcing that is given publicity.
There are several books like that (a lot of them by Gould).
> It actually makes no difference at all who says anything in science, because it should be examination of the data that leads to a conclusion, not examination of a scientist's reputation.
This is not entirely true. I am the last person to say a dissenting scientists should be silenced but the public simply cannot go into detail in any of several subjects. A good example is client change – no single person in the public is smart enough to know all facets of climate change science.
The public view is largely made up of the consensus view of a lot of scientists – but that does not mean that there is no place for the Bjorn Lomburgs.
The intelligence debate is the same – we should not rely on a single scientist. No single scientist is a master of all the fields (from neurobiology to psychometrics).
It is unfortunate that the politically correct view (the “ought to”) is promoted over the actual science. Public press is not representative in what goes on in the research.
> “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,
That is true – and Jensen is correct in that. Flynn is in many cases the most prominent proponent of many views. My problem with Flynn is twofold.
The first problem is that he is a political scientists and he tries to defend the “ought to” - instead of trying to search for the “is”. If he was just active in intelligence research (instead of politics) it would be fine.
The second problem is that several scientists near the intelligence debate is viscously attacked for where they get their funding (in a politically motivated attempt to cut of funding). Their scientific objectivity was questioned and it is really ugly. Flynn is active in politics – yet no one attacks his scientific objectivity. It is a double standard that is simply not right.
no one attacks his [Flynn's] scientific objectivity
Yes, because he has demonstrated his scientific objectivity by changing his point of view from time to time, digging up new evidence when scientists say his previously offered evidence is inadequate, and scrupulously honoring his most ardent opponents with credit when their counterarguments prompt him to reconsider his previous publications. What Flynn writes in the early twenty-first century about IQ is much better quality research than what he wrote in the 1970s. (It's important to point out that already by the 1980s he was being published in Psychological Bulletin, the most prestigious journal in psychology, because his articles were meeting a high standard of scholarship.) Take a look at which psychologists and sociologists praise Flynn, his research in general, or his latest book on the Amazon.com page for his latest book:
Ian Deary, Edinburgh University
Charles Murray, American Enterprise Institute & co-author of The Bell Curve
> Yes, because he has demonstrated his scientific objectivity by changing his point of view from time to time, digging up new evidence when scientists say his previously offered evidence is inadequate, and scrupulously honoring his most ardent opponents with credit when their counterarguments prompt him to reconsider his previous publications.
This is true for Jensen and several other researchers - yet they are treated as pariahs in the public arena.
Several have questioned the objectivity of Jensen (and other researchers). As I have said before, James Flynn is both a passionate left-wing politician and he freely admits that he is egalitarian. E.g. in “How to defend Humane Ideals: Substitutes for objectivity”:
> This book was written by someone committed to humane-egalitarian ideals...
So, how can anyone question Jensen's objectivity but not that of Flynn?
There are several attacks on Jensen and others holding up Flynn as the poster boy (see at the end). Flynn has not done anything to dispel that. He even wrote a book attacking Jensen indirectly (Race, IQ and Jensen). Here is a quote:
> However, the last stand of the racist is not without importance, something I will attempt to demonstrate by giving a racist ideologue his say.
Scientists should search for truth – with not prior preconceptions or beliefs (i.e. he should search for truth and not just justification).
Here is an example of some Jensen attacks:
“Resurrecting Racism: The modern attack on black people using phony science” (by the popular anthropologist Francisco Gil-White):
I will not quote it since the whole chapter is full of Jensen attacks.
The extremely popular “The Mismeasure of Man” by Stephen Jay Gould also have the same attacks Jensen and others.
The list goes on. There is a saying that I translated to English: “They are not sheared over the same comb” i.e. Flynn are treated differently than those with opposing viewpoints.
It actually makes no difference at all who says anything in science
We aren't talking about physics where the variables are defined precisely. We are talking about psychology which is a pseudo-science at best as there are so many components that one may not really know what caused what or if it was something else that caused it. So when it comes to pseudo-science, a place where research is mosaic with many studies supporting the hypothesis and many others not, there is plenty of room for authors bias.
As for the debate of nature v nurture you to are having, one of you summed it up pretty well, the environment causes changes in the brain, but the question is a bit circular, namely did the brain make the person seek out the environment which led to the changes of the brain, or was the environment unrelated to the agents intentions. Anyhow, the question is not which one it is, but to what extend does nurture or nature influence. So its proportionality not absolutism.
There are numerous studies that also show that the general intelligence factor is due to physiological effects (e.g. size of different areas of the brain, etc...). How do you explain that?
There is a theory on why when people are trained in a task they do better – it turns out that the amount of “general intelligence” used is less. There are also studies that show this effect with PET scans of the brain:
> Thus, the largest GMR decreases with practice were found on subtests with the highest g loadings. Jensen noted this finding was consistent with what he termed the conservation of g. Namely, with practice and training, tasks become more automatized and require less g.
(from Haier [1])
There is a recent study (2008, te Nijenhuis ,van Vianen , van der Flier [2]) that shows that the increase in RSPM and other scores is because of training and is not an increase in the overall general intelligence [2] (the studies that you cited is all 8 years or older). Incidentally this study cites two of the Flynn papers that you cited (Massive IQ Gains in 14 Nations: What IQ Tests Really Measure, IQ Gains, WISC Subtests and Fluid g: g Theory and the Relevance of Spearman's Hypothesis to Race).
The idea that Flynn proposes (i.e. that general intelligence is increased over time is dismissed). Here is a full quote of the abstract of the paper (if you need the full paper and do not have access to it, msg. me and I will email it for you):
IQ scores provide the best general predictor of success in education, job training, and work. However, there are many ways in which IQ scores can be increased, for instance by means of retesting or participation in learning potential training programs. What is the nature of these score gains? Jensen [Jensen, A.R. (1998a). The g factor: The science of mental ability. London: Praeger] argued that the effects of cognitive interventions on abilities can be explained in terms of Carroll's three-stratum hierarchical factor model. We tested his hypothesis using test–retest data from various Dutch, British, and American IQ test batteries combined into a meta-analysis and learning potential data from South Africa using Raven's Progressive Matrices. The meta-analysis of 64 test–retest studies using IQ batteries (total N = 26,990) yielded a correlation between g loadings and score gains of − 1.00, meaning there is no g saturation in score gains. The learning potential study showed that: (1) the correlation between score gains and the g loadedness of item scores is − .39, (2) the g loadedness of item scores decreases after a mediated intervention training, and (3) low-g participants increased their scores more than high-g participants. So, our results support Jensen's hypothesis. The generalizability of test scores resides predominantly in the g component, while the test-specific ability component and the narrow ability component are virtually non-generalizable. As the score gains are not related to g, the generalizable g component decreases and, as it is not unlikely that the training itself is not g-loaded, it is easy to understand why the score gains did not generalize to scores on other cognitive tests and to g-loaded external criteria.
So what we have for the immutability of general intelligence is a theory, intelligence test results confirming the theory and PET scans of the brain showing this effect.
[1] Richard J. Haier, Ph.D., Positron Emission Tomography Studies of Intelligence: From Psychometrics to Neurobiology
[2] Jan te Nijenhuis , Annelies E.M. van Vianen , Henk van der Flier, Score gains on g-loaded tests: No g
PS: This reply is a little long so sorry for that.