I’ve been following the debates regarding the “black-white iq gap” and whether it is hereditary or environmental and one confusing thing just recently occurred to me:
Those on the hereditary side always say that mixed race people (half black-white) have IQs that are midway between that of blacks and whites. Now my question is: Then why is the average IQ of African Americans 85 instead of a number much closer to the purported black African average of 70 since African Americans are genetically about 80% black?
In other words, wouldn’t an IQ average of 85 (which is exactly midway between 70 and 100) make more sense if African Americans were literally a mulatto race, which they are not?
Is it actually 70? Got a cite for that? I’ve yet to see any reasonable study that measures the average IQ across the African continent.
That’s actually one of the major problems with any studies that purport these kinds of results. They’re often based on spectacularly poor studies and extreme extrapolations.
Not necessarily. Even if we assume measured intelligence is purely genetic in origin, which we know is false, exactly how that expresses itself by heritage isn’t going to be clear. Using ratio of admixtures between two fixed points is a dangerous assumption to make here.
It is often claimed to be 70 (or even less) among those on the hereditary side of the debate (euphemism for “racists”) such as Phillippe Rushton, the authors of “The Bell Curve”, and many others.
I am not personally assuming the gap in test scores to be genetic. I am simply taking the assumptions of those who say it is and asking a question about it?
Even so, it’s not necessarily the case that using the ratio of inherited genes should produce resulting intelligence.
We know genetics is only one part of how intelligence expresses itself, so a weighted average doesn’t necessarily make any more or less sense than some kind of straight averaging or using the maximum of the parents or anything else. And all this is compounded by all the problems the non-genetic stuff introduces, meaning it’s pretty hard to separate out the genetic effect from everything else.
One cannot ask why something is true without first establishing that it IS true. Otherwise, any explanation is meaningless.
But if we ignore that and accept that:
-IQ tests are a good measure of intelligence (they aren’t)
-Intelligence is largely hereditary (not known, but there is certainly a HUGE cultural, nongenetic factor with IQ tests)
-Black Africans have a meaningful average IQ of 70 (I’d be willing to bet they don’t)
and
-African-Americans have a meaningful average IQ of 85 (I’d be willing to bet they don’t)
then you’re still making some huge assumptions about how the genetics work. You’re assuming a simple additive model, where you get some level of IQ from mom, and some level of IQ from dad, and they simply average out like real numbers.
Genetics doesn’t work like this. There are innumerable ways that genes can interact and produce interesting phenotypes. Even the simplest dominant/recessive relationship wouldn’t give you the results you seem to think should apply.
The point is that even if all this nonsense WERE true, there would be a huge amount of work to figure out what genes are involved, what alleles exist, and how they all interact.
The IQ distributions of other racial and ethnic groups in the United States are less well-studied. The Bell Curve (1994) stated that the average IQ of African Americans was 85, Latinos 89, whites 103, East Asians 106, and Jews 113. Asians score relatively higher on visuospatial than on verbal subtests. The few Amerindian populations who have been systematically tested, including Arctic Natives, tend to score worse on average than white populations but better on average than black populations.
I know. But the claim that mixed race kids have average IQs that are “midway” between the two races is a common claim among the hereditarists. For example, the claim is made “Race Differences in Intelligence” and also in “The Bell Curve”.
As evidence, here is a critique of the first book by Nicholas Macintosh:
The answer is that the genetic explanation doesn’t make any sense on several different levels. The evidence behind the claim that the IQ of the average African is 70, for example, comes perilously close to “made up.”
Whereas I am of the opinion that one should find out if something is true before trying to find out why something is true. This prevents one from giving legitimacy to something that may not be true after all.
Perhaps what they say is that, all things being equal, one would expect the average IQ of half white/half blacks to be about half way between the average for blacks and whites.
I would guess it’s because African-Americans have the advantage of growing up in a country with far better nutrition; education; and sanitation than that of most black Africans.
If everywhere in the world had basically the same sanitation; education; nutrition; etc., then yes it would.
But, even if we accept the numbers as claimed (which is perilously close to being willfully blind to bad science), the result still could be correct even if the mechanism they use to justify it is not.
And that’s a real problem dealing with pseudo-science sometimes. It’s quite easy to come up with a post-hoc explanation for observed phenomena. The mechanisms used to describe it may not be correct, but the actual measurements can still be valid. But convincing true believers that the “just-so” stories used to explain it are scientifically suspect and not particularly convincing is not easy.
And The Bell Curve, being pseudo science in support of a political agenda, is worthless as a source of information regarding intelligence, although it is probably one significant source of the “many” web sites to which bita malt has alluded.
The Bell Curve did an excellent job in its early chapters of describing the history of attempts to measure intelligence. In its later chapters, when it tried to actually discuss the results of those efforts and make “scientific” predictions based on those efforts, it failed miserably except as a bit of political polemic. Among its “studies” it included contrasting unlike studies of different groups at different ages and different educational levels and then claiming that they produced “equivalent” results. It also used studies with populations too small to be relevant to any scientific investigation. It was crap.
As noted, an IQ of 70 is considered to be the level at which a person would be severely limited in their ability to perform any adult tasks. Studies that claim an average IQ of 70 for sub-Saharan Africa, (in which 50% of the population would have intelligence below that required to function as a person in the real world), are absurd and should have caused those who came up with such figures to recognize that either their methods of testing IQ or the reality of IQ, itself, were so much rubbish.
Virtually all those who identify as African Americans are “mulatto” by racist criteria – they range from 50% to 80% sub-Saharan African in genetic makeup. The other part is virtually always from white male ancestors. So say the studies.
The “85” number is not “discussing the results” or “making predictions”. It is basic data. Did anyone criticizing “The Bell Curve” dispute that number? If so, I’d like a cite. And if you have contradicting stats, please show them.