Dancing David
Penultimate Amazing
Science as racism?
- Thread starter Dancing David
- Start date
I have no idea about the heritability numbers, but whoever did this study is banking on people knowing very little about intelligence testing. WAIS-III, the test that I am most familiar with, and one of the most respected and widely-used IQ tests out there, gives a score with error margins. A 3-point error margin would be a minimal margin, and it's not that uncommon to see 10 point error margins, or higher, depending on which confidence interval one uses, and the degree of accuracy in the administration of the test. Furthermore, the same person being tested twice with this test would, on average, have scores that are different by about 5 points. If that person had been trained in the kinds of tasks used in the test in between the two tests, the difference would be even higher. So to me, it's ridiculous to claim that IQ tests are precise to the point that they won't change more than 3 points.
Edited: Forgot to add, there is, in fact, a documented 3-point difference in IQ scores between Americans as a whole and Canadians as a whole, discovered during the original norming process. The average Canadian IQ is 103, not 100. Given that the two cultures have similar genetic makeup and variety, share a language and mostly share a culture, I do wonder how the authors of the article would like to explain this one away. The way the difference is used in practice is to ignore it, because really, the usual error margins more than cover the difference, anyway, and the only time it becomes important is when the score is on the borderline of a cutoff that will determine what kinds of services someone receives.
Edited: Forgot to add, there is, in fact, a documented 3-point difference in IQ scores between Americans as a whole and Canadians as a whole, discovered during the original norming process. The average Canadian IQ is 103, not 100. Given that the two cultures have similar genetic makeup and variety, share a language and mostly share a culture, I do wonder how the authors of the article would like to explain this one away. The way the difference is used in practice is to ignore it, because really, the usual error margins more than cover the difference, anyway, and the only time it becomes important is when the score is on the borderline of a cutoff that will determine what kinds of services someone receives.
Last edited:
I don't understand how they came to the 80% heritability. Also, this was a fairly cursory description as most press releases are. It doesn't describe anything about how the study was conducted, where they obtained their data, and how many subjects were involved. This is all it said:
Also, I have to wonder whether a 15-point gap in average IQ scores between two very heterogeneous populations is important anyway, especially in light of the margins for error and variation among individuals tested on separate occasions that Avita mentioned.
Having said that, if (big "if") what they found is true, how would it be racism?
So you have four different tests here. How many of the subjects took all of them, one of them, two? If each only took one, can the scores really be compared across them? I don't know very much about each of these tests, but this seems like a bit of a methodological flaw.
Also, I have to wonder whether a 15-point gap in average IQ scores between two very heterogeneous populations is important anyway, especially in light of the margins for error and variation among individuals tested on separate occasions that Avita mentioned.
Having said that, if (big "if") what they found is true, how would it be racism?
That's not science.
Oh, my, what I lost by only barely skimming the article - thanks, Katana, for listing the actual tests they used. The Kaufmann and the DAS I know little about, but they are administered only with children, so right away, I wonder about them being generalized to adults. The WJ is not an IQ test - it is two batteries of a variety of subtests, one battery focusing on cognitive performance, and the other on "achievement" - that is, knowledge gained through learning, rather than innate ability. Although the cognitive components are often similar to the tasks used on IQ tests, the WJ is not designed to produce a single score comparable to an IQ score. A major reason for that is that hardly anybody ever administers the complete battery of tests - it takes far too long, and is usually unnecessary for the purposes of assessment. Finally, the WPT, from the brief description of it that I just read, seems to be designed to be comparable to an IQ test, but takes 12 minutes to administer. By comparison, the WAIS takes at least 2 hours. For some reason, I am highly doubtful that the results on the WPT are all that accurate. And I am left with the burning question - since all four of the tests the researchers used don't seem to be adequate for the assessment of IQ, why in the world were those four tests selected in the first place? Could it be because these tests produced the results the researchers wanted?
Jensen is well-established to be complicit in the "fraudulent" school of IQ studies as established by Cyril Burt.
Thanks for that perspective, Avita. This study is sounding less and less credible.
Thse always struck me as more about binary race construct than science. Where is everybody who is neither black nor white? Where are the people who are both? In varying degres and percentages? I'd like to see studies like this done and reported with more comprehensive and meaningful genetic subpopulations.
I would like research into intelligence(s) and subpopulations to continue, and to be reported and discussed, but I'd like to see more critical thought and open-ended inquiry going into it.
Agreed. Haven't we learned that black versus white isn't a (ahem) black and white issue genetically?
I was thinking about the thread's title. Whether racism was the underlying motivation for publishing this study, I don't know. I googled both authors, and it is clear that they have made their careers on their somewhat controversial views of race, genetics, and intelligence. For them, this study is another piece of evidence that what they have been saying all along is correct.
Dancing David
Penultimate Amazing
I used a question mark? To denote that this might or might not be racism, and it is also an attention grabber in the title.
If it is found to be true then it raises all the usual questions about what different factors effect an IQ score that are not associated with race.
bpesta22
Cereal Killer
- Joined
- Jul 31, 2001
- Messages
- 4,942
As argued in the thread on Spearman's g, as skeptics, perhaps you should read the article before attempting to discredit it.
It's only 2 pages; I will email it to anyone who wants it.
Don't mistake ignorance of the field for junk science.
It's only 2 pages; I will email it to anyone who wants it.
Don't mistake ignorance of the field for junk science.
bpesta22
Cereal Killer
- Joined
- Jul 31, 2001
- Messages
- 4,942
100 years of worth of evidence to be correct. Just one example of the evidence comes from a meta-analysis (2001) of 6,246,729 people.
The only thing Rushton and Jensen claim in this specific article is that the race gap is not shrinking, despite what Dickens and Flynn argue in the same issue.
bpesta22
Cereal Killer
- Joined
- Jul 31, 2001
- Messages
- 4,942
They reference their earlier work-- Rushton and Jensen 2005, wherein they show that the race difference correlates with the g factor; not the specific test of IQ used in each study. From any of the tests used, one can get the g score and use that for the correlation.
If these guys are racist it's odd that they-- in the same 2 page article, though not talked about in the media discussion of it-- argue the asian mean IQ is 106.
So, they're the particular blend of white racists who think they're better than blacks but not quite as good as Asians?
It's interesting that this is a press release by Rushton. Dancing David, how did you come across it?
My big question is how is race determined in the recent tests? Self-identification? What about all the research by population geneticists showing that there is considerable african-european admixture in America? And how are latinos (a huge portion of the American public today) categorized and how do they impact this data?
bpesta22
Cereal Killer
- Joined
- Jul 31, 2001
- Messages
- 4,942
You're ignoring the principle of aggregation and how that affects margins of error.
Sure, study one person's IQ and it might vary by 3 or 5 or 10 points over time, tests and testers.
Study 1000s of people classified on some dimension (e.g., race) and this becomes far less of a problem. Whether one is studying IQ or agression, any test measuring one or the other construct would be validated by using lots of people and not one or two.
Even the the classical model of reliability (invented by Spearman, coincidentally!) assumes this: A person's observed score on a test = his or her true score, plus error.
Errors can be positive (artificially inflate your score) or negative (artificially reduce your score). For any single person, the error score might be very large, but test large groups of people and the error scores become normally distributed with a mean of zero!
In fact, one can use the idea of error to make a fairly ingenious (imo) prediction: If the black white gap is real, then regression to the mean should occur differentially for black and white parents re their kids IQ's. That is, people selected based on an extreme IQ score should have kids whose IQ regresses back to the race group mean IQ.
The original study referenced in the OP (rushton and jensen) reviews lots of data on this issue.
Match two couples (one white; one black) on SES, income, education, etc, and IQ. The key is to match on extreme IQs to then observe how the kids' IQ regresses to the mean.
So, some matched couples will have IQ's of 120; others IQ's of 70.
For the 120-IQ parent group, their black kids' average 100 for IQ; wheras, the white kids average 110. So, regression to the mean is twice as strong for black kids, because the black kids are regressing to their group mean of 85-- a longer distance away; whereas, white kids are regressing to their group mean of 100-- a shorter distance away (and hence less regression).
Just the opposite happens for matched parents with IQs of 70-- regression up to the mean is twice as strong for the kids with white parents!
The black kids' IQ is now 78 (half the difference up to their true mean) and the white kids IQ is now 85 -- more regression for whites because the distance to their true mean (100) is now farther.
Any gouldists out there who can suggest an environmental or cultural explanation that accounts for this pattern of regression to the mean?
bpesta22
Cereal Killer
- Joined
- Jul 31, 2001
- Messages
- 4,942
Oh, finally, the original article-- rushton and jensen, 2005, is a lit review of some 30 years of research on the issue.
It's 60 pages long, but it's worth the read to the extent you want answers to these questions. At the very least, reading it should convince you that arm chair dismissals here from people not in the field are inaccurate and frankly naive (e.g., that a chemist could come in, think for 60 seconds, and generate problems/flaws in the study that would not have occurred to the person with the phd in the area and 200 pubs on the topic).
Yahzi's famed cultural hypothesis, for example, is thoroughly trashed, though, I'm not sure that Jensen is aware of the gorilla study.
It's 60 pages long, but it's worth the read to the extent you want answers to these questions. At the very least, reading it should convince you that arm chair dismissals here from people not in the field are inaccurate and frankly naive (e.g., that a chemist could come in, think for 60 seconds, and generate problems/flaws in the study that would not have occurred to the person with the phd in the area and 200 pubs on the topic).
Yahzi's famed cultural hypothesis, for example, is thoroughly trashed, though, I'm not sure that Jensen is aware of the gorilla study.
Just as an example of how utterly shoddy these people's work is:
When they say "Asian," what do they mean? Did these people ever go to, you know, Asia, and adminster any tests?
Why... no. They have deduced the IQ of half the planet from the sample which chose to emigrate to California.
First-class science here, folks! We don't need no stinking data!
Theologians say exactly the same thing. In exactly the same tone of voice.
Notice how he puts "would not have occurred" above, as if these clever people can be counted on to be aware of all the relevant facts. And then, in the very next sentence, admits they are unaware of the most basic facts:
Jensen, being a Genius Of The First Order, can safely dismiss data he is utterly unaware of. But heaven forbid the Yahzi dog should sniff a steaming pile of fecal matter and declare it stinky.
Earthborn
Terrestrial Intelligence
I don't understand what you mean with "if the black white gap is real". Are you refering to a cultural gap or a difference in average IQ? Does "real" mean in this case mean "existing" or "caused by innate differences" ?
Wouldn't the same effect occur if the differences in average IQ are real, but caused by cultural influence?