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Science Forum Index » Cognitive Science Forum » Different IQ-gap explantions
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| Ulf Persson |
 Posted: Mon Feb 09, 2004 1:46 pm |
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There seems to be _very different_ views on the nature of experts
views about the black-white IQ -test score gap.
"There is no definitive answer to why IQ bell curves differ across
racial-ethnic groups. The reasons for these IQ differences between
groups may be markedly different from the reasons for why individuals
differ among themselves within any particular group (whites or blacks
or Asians). In fact, it is wrong to assume, as many do, that the
reason why some individuals in a population have high IQs but others
have low IQs must be the same reason why some populations contain more
such high (or low) IQ individuals than others. Most experts believe
that environment is important in pushing the bell curves apart, but
that genetics could be involved too." [1]
"The differential between the mean intelligence test scores of Blacks
and Whites does not result from any obvious biases in test
construction and administration, nor does it simply reflect
differences in socio-economic status. Explanations based on factors of
caste and culture may be appropriate, but so far there is little
direct empirical support for them. There is certainly no such support
for a genetic interpretation. At this time, no one knows what is
responsible for the differential. " [2]
The above seems hard to square with this:
In the book by Rothman and Snyderman The IQ Controversy [3], the
authors polled 1,020 experts in the issues surrounding psychometry on
numerous matters, including their opinion about the heritability of
black-white differences in IQ.
According to the survey: "The source of black-white difference in IQ.
This is perhaps the central question in the IQ controversy.
Respondents were asked to express their opinion of the role of genetic
differences in the black-white IQ differential. Forty-five percent
believe the difference to be a product of both genetic and
environmental variation, compared to only 15% who feel the difference
is entirely due to environmental variation. Twenty-four percent of
experts do not believe there are sufficient data to suport any
reasonable opinion, and 14% did not respond to the question. Eight
experts (1%) indicate a belief in an entirely genetic determination."
Does anybody knows of another and newer poll of experts in the
IQ-field? I can not find any with my limited search options. The poll
seems to make a _much_ stronger case for a genetic interpretation of
the test score gap than the other two expert opinion pieces.
[1] Mainstream Science on Intelligence, The Wall Street Journal,
December 13, 1994.
[2]APA Task Force Examines the Knowns and Unknowns of Intelligence
http://www.apa.org/releases/intell.html
[3] The IQ controversy, the media and public policy / Mark Snyderman
and Stanley Rothman. New Brunswick, N.J., USA : Transaction Books,
c1988. |
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| Wolf Kirchmeir |
| Posted: Mon Feb 09, 2004 1:46 pm |
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On 9 Feb 2004 10:46:23 -0800, Ulf Persson wrote:
Quote: There seems to be _very different_ views on the nature of experts
views about the black-white IQ -test score gap.
....snip...
AFAIK, the difference in the average IQs of black and white groups in the USA
is less than the average difference between IQs of any two Americans taken at
random, which to my mind means there is no significant difference.
--
Wolf Kirchmeir, Blind River ON Canada
"Nature does not deal in rewards or punishments, but only in consequences."
(Robert Ingersoll) |
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| Ulf Persson |
| Posted: Wed Feb 11, 2004 6:19 pm |
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"Wolf Kirchmeir" <wwolfkir@sympatico.can> wrote in message news:<jbysxveflzcngvpbpna.hsu7a91.pminews@news1.sympatico.ca>...
Quote: On 9 Feb 2004 10:46:23 -0800, Ulf Persson wrote:
There seems to be _very different_ views on the nature of experts
views about the black-white IQ -test score gap.
...snip...
AFAIK, the difference in the average IQs of black and white groups in the USA
is less than the average difference between IQs of any two Americans taken at
random, which to my mind means there is no significant difference.
The differences are statistically significant, but I read your
statement as saying that the differences are not significant in real
life terms.
How do you reason? I have never seen a study where you select a lot of
person pairs and asign the ones with higher IQs to one group and the
other of the pair to another group, and then compare the groups on a
variety of dimensions.
The parts that to my mind are most at ods with each other are:
"There is certainly no such support for a genetic interpretation"
(APA)
and
"Forty-five percent believe the difference to be a product of both
genetic and
environmental variation..." (Rothman and Snyderman)
Which interpretation should you trust? The APA task force is newer but
the Rothman and Snyderman survey is based on an much larger base of
experts (bear in mind that about 50% didnt respond). |
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| Wolf Kirchmeir |
| Posted: Thu Feb 12, 2004 6:57 am |
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On 11 Feb 2004 15:19:15 -0800, Ulf Persson wrote:
Quote: "Wolf Kirchmeir" <wwolfkir@sympatico.can> wrote in message news:<jbysxveflzcngvpbpna.hsu7a91.pminews@news1.sympatico.ca>...
On 9 Feb 2004 10:46:23 -0800, Ulf Persson wrote:
There seems to be _very different_ views on the nature of experts
views about the black-white IQ -test score gap.
...snip...
AFAIK, the difference in the average IQs of black and white groups in the USA
is less than the average difference between IQs of any two Americans taken at
random, which to my mind means there is no significant difference.
The differences are statistically significant, but I read your
statement as saying that the differences are not significant in real
life terms.
Precisely, since the demand on "intelligence" in real life rarely exceeds the
capability of the average person. And where it does, we have experts, who are
often smart but not so often wise. :-)
Quote: How do you reason? I have never seen a study where you select a lot of
person pairs and asign the ones with higher IQs to one group and the
other of the pair to another group, and then compare the groups on a
variety of dimensions.
I don't see what this has to do with the question. I do know that people have
computed the average difference between members of a group (it's easy to do,
and I'm sure you know how to do it), and that this has turned out to be
greater than the (demonstrated) difference in average IQ scores of whites and
blacks in the USA. In fact, AFAIK this is a common observation when groups
are compared along any variable dimensions.
IOW, my point, more explicitly stated, is that the group difference is a
difference that doesn't make a difference.
Quote: The parts that to my mind are most at ods with each other are:
"There is certainly no such support for a genetic interpretation"
(APA)
Quote: and
"Forty-five percent believe the difference to be a product of both
genetic and
environmental variation..." (Rothman and Snyderman)
Which interpretation should you trust? The APA task force is newer but
the Rothman and Snyderman survey is based on an much larger base of
experts (bear in mind that about 50% didn't respond).
The experts who say that the "difference to be a product of both genetic and
environmental variation" aren't saying anything useful, really. Almost all
differences between people are the product of both genetic and environmental
variation. The ones who say that there is no support for the genetic
variation theory are also right - there is no such support, since we don't
have the tools to find it (and quite possibly never will have.)
The rest is some elaboration on that comment, and probably not necessary.
IMO we just don't know enough about the interaction of genes and environment
to be able to judge any explanation of the difference in group IQs. That's my
position, really. We know a few odds and ends, such as that nutritional
deficiencies in infancy can cause permanent intellectual deficits (as
measured by IQ tests), or that exposure to alcohol (and other chemicals) in
the womb can cause deficits, etc. We know that family environment and
expectations have a great deal to do with scholastic achievement, and that
scholastic achievement and IQ correlate (but there's no evidence IMO that one
causes the other -- on the contrary, I've known far too many high IQ kids who
achieved at average or lower levels in school.) We know that IQ tests results
are affected by the time of day, the time since the last meal, and what was
in the meal, etc. We know that in children IQ varies over time. For these and
other reasons I automatically assume that any IQ number near 100 is +/-5, and
as you approach either end of the scale, the error becomes larger.
In any case, IQ numbers are "massaged" percentiles, _not measures_, which
should give you pause.
That there are genetic factors in intelligence is IMO obvious. What they are,
and how they interact with environmental factors is not. That's because, with
a very few exceptions, it is very ill understood how genes interact with the
environment and even less how they interact with each other. The recent
realisation that epigenetic factors are at least as important as genes in the
development of an organism complicates the picture so much that we can't IMO
make any kind of generalisation about genes and intelligence, except the
empty one that there is a connection.
--
Wolf Kirchmeir, Blind River ON Canada
"Nature does not deal in rewards or punishments, but only in consequences."
(Robert Ingersoll) |
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| neepy |
| Posted: Mon Feb 16, 2004 9:23 am |
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"Wolf Kirchmeir" <wwolfkir@sympatico.can> wrote in message news:<jbysxveflzcngvpbpna.hszdsd3.pminews@news1.sympatico.ca>...
Quote:
IOW, my point, more explicitly stated, is that the group difference is a
difference that doesn't make a difference.
That sounds too much like Lester Zick for my liking. |
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| N |
| Posted: Sat Feb 21, 2004 8:47 pm |
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dsutherland7@hotmail.com (neepy) wrote in message news:<d4bd1f7c.0402160623.7e12b4e8@posting.google.com>...
Quote: "Wolf Kirchmeir" <wwolfkir@sympatico.can> wrote in message news:<jbysxveflzcngvpbpna.hszdsd3.pminews@news1.sympatico.ca>...
IOW, my point, more explicitly stated, is that the group difference is a
difference that doesn't make a difference.
This isn't my sort of thing, but I think that enviromental factors play
the most important part here. Ones aptitude for a subject is not
necessarily quantifiable, nor are an individuals constructive
contributions in unrecognised environments.I also think that people
can be trained to improve at certain subjects. In my own experience
having missed a lot of schooling, the most devastating effect was
poor communication skills, but I was fortunate in that I had a
mentor who encouraged me in art. When I was in my teens my estimates
were, 87, 115, and two above 160, I made a great effort to readjust
those and get a life!. |
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