The Myth of Race: The Troubling Persistence of an Unscientific Idea

He has a lot of posts to respond to. Give him some time. This is the first time I've gotten a scholar to post on a message board like this. They are usually too busy or too inexperienced to respond beyond email so for Dr. Sussman to show up at all is pretty significant.

 

Indeed.

I have been very successful in shutting down racists across the internet with these quotes. Doing the Google search myself was like a walk down memory lane. This just goes to show that most racists are not prepared to debate the content of the arguments of evolutionary biologists like Graves. They call the arguments "incoherent" even though he was able to simplify them. Rushton never responded to Graves in print and during my email exchange between the two with Frank from The Phora Rushton was shut down after a brief forwarding of emails.

No one has really taken Graves to task on his critique of Rushton. Well you tried but he shut you down too.

I would dispute the contention that the measured differences in intelligence are "vast". Major differences in intelligence would be like comparing a genius to a retard. There's no evidence regardless of the cause of IQ differences that for instance Whites are far superior in intellect to Blacks. What can the average White person do mentally that a Black person can't do?

Actually he did address this study. I looked at the index and found the study was covered by pages 250-252. It's a very good read which exposes the many flaws in the type of twin studies conducted by Thomas Bouchard.

I don't know if Sussman covered this study but Nisbett certainly did.

You're making assumptions. You should really read the book before you assume its content.

I see what you're driving at, I have a few comments to make and hopefully Dr. Sussman can provide his perspective on your method of testing.

1. Digit span is a component of IQ testing but not a test of IQ by itself. It's well-known that IQ tests can be culturally biased so digit span may be "culture-neutral" but it tests memory more than anything.

2. What is the purpose of the "genetic blood test?" If you're saying that DNA testing should be done to see if there is a correlation between IQ and racial/ethnic ancestry then I agree a DNA test is useful but it has to be done in a way to ensure that there is a relationship between continental ancestry and intelligence. The argument of Egalitarians is that the nurturing environment between so-called races is unequal therefore they score differently on IQ tests and have unequal life outcomes.

3. Several scholars have shown that there is no relationship between variation in brain size and intelligence, notably Leonard Lieberman in his demolition of the arguments of Rushton. You have to show that there is a relationship between brain size and intelligence independently before assuming that MRI scans are going to tell us anything about race and intelligence.

I doubt you are going to find independent researchers who are unaware of theories or goals. They will know very well what they are testing for. But if multiple credible researchers conducted such testing and came to the same results then you could make the argument that your position has been proven empirically or has been scientifically falsified depending on the result.

Incidentally if you read the Nisbett article I linked to you will find that 5 different types of racial admixture studies were conducted which showed that there was no relationship (statistically low correlation) between degree of White ancestry and high Black IQ. If your gene-based theory were correct then it would have to be the case that interbreeding between Blacks and Whites makes the admixed children smarter. African-Americans have 20%-30% European ancestry making this natural experiment possible. The studies looked at blood groups, skin color, facial features and other indicators of mixed heritage to see if the more admixed African-Americans were smarter and it was simply not the case. I would like to see if these results could be duplicated with modern genetic testing. If so it would be the nail in the coffin to racialist arguments or vindicate them if it showed something different.

Anyway I'd like to see what Dr. Sussman has to say about this and the other questions directed at him.

 

Jewish Marxist clowns post their garbage everywhere bro. WTF?

 

There are competing effects.

First I would argue that white women who get pregnant by a Black man are stupid, so this no doubt has a lowering affect on the statistical IQ of mixed-race individuals.

Second, there are potential negative affects resulting from intermixing. It could even possibly lead to lower intelligence.

An analysis of more than 3 million respondents revealed the average pay was $15.74 per hour for people of mixed race, $17.39 for black people and $22.04 for white people. This was despite the fact that 18 per cent of mixed-race people had college degrees, compared with 11 per cent of black people and 28 per cent of white people.
"Can the 'one-drop rule' tell us anything about racial discrimination? New evidence from the multiple race question on the 2000 Census", Robert W. Fairlie
University of California, Santa Cruz

A study by J. Richard Udry’s National Longitudinal Study of Adolescent Health, which sampled a random, nationally representative school-based sample of U.S. adolescents in grades 7 through 12, during 1994-1995, showed an increase in behavioral problems amongst mixed-race children, as well as significantly higher rates of asthma, and generally poorer health. Another interesting finding was that mixed children that had a black parent were significantly more likely (63% more) to have skin problems.
J. Richard Udry, Janet Hendrickson-Smith, Carolina Population Center, University of North Carolina at Chapel Hill, 2003

There are immune related inflammation issues, and this has an effect on cognitive thinking ability. Might only manifest in a small number of individuals, but still affects the statistical average.

 

I would argue that this statement is an expression of your bigotry rather than a scientific fact.

I doubt it.

That doesn't seem to support any theories concerning the effects of genetic admixture.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448064/

Conclusions. Adolescents who self-identify as more than 1 race are at higher health and behavior risks. The findings are compatible with interpreting the elevated risk of mixed race as associated with stress.

Come on now. You are interpreting these studies as race-mixing having a deleterious effect on offspring when the authors clearly suggest these health and behavioral risks are related to stress.

Unless you can show that there is a biological component related to race-mixing itself which causes these immune related inflammation issues it is irrelevant.

As it stands the racial admixture studies I'm talking about not only looked at biracial blacks (most of whom do come from Black male-White female couplings) but indicators of racial admixture in general. Most of the European ancestry in African-Americans comes from interracial sex (rape) during slavery between White male slave masters and Black female slaves yet there is no relationship between high Black IQ and degree of White ancestry. Slave masters were mostly wealthy Whites who presumably had higher IQs than the average White so one would expect this ancestry to give Blacks an IQ boost if Whites really were on average smarter than Blacks, yet it doesn't.

 

But it is a valid possible explanation.

 

Even if it were true it is of no relevance to the racial admixture studies I'm citing because most European Ancestry in African-Americans comes from wealthy White men.

 

No, came from wealthy white men (in the past). And it was mostly diluted away over time into the larger black gene-pool. The "mixed race" african-white people of today are mostly descended from white women. Did those racial admixture studies look at amount of european DNA marker composition in each individual, or did they just look at people who were recognised as "mixed race" ?

 

As I said before, they looked at indicators of mixed ancestry such as skin color and facial features, meaning they didn't simply look at people identified as mixed race. I agree with you that most interracial relationships today between Blacks and Whites are between Black men and White women but most of the European ancestry in African-Americans comes from slavery. They looked at both people identified as biracial and people who simply looked more admixed and did not find a relationship between high Black IQ and degree of White ancestry.

But as I also pointed out these were not modern DNA studies which would be more reliable. They looked at blood groups, skin color and facial features.

Here is the information I'm talking about:

Direct Tests of Heritability of the Black–White IQ Difference

Most important, Rushton and Jensen (2005) ignore or misrepresent a large
literature dealing with the most direct sort of evidence, which relates to the
influence of European ancestry on Black intelligence. U.S. “Black” populations
contain as much as 30% European genes. This means that an individual who is
identified as Black could have anywhere from 100% African ancestry to mostly
European ancestry (true of as much as 15% of some U.S “Black” subpopulations;
Herskovits, 1930). This allows us to identify the extent to which percentage
African ancestry, variously assessed, is associated with IQ. Five different types of
studies allow for an estimation of the effect of relatively African versus relatively
European genes on IQ. I report these below in increasing order of what I take to
be their probativeness.


Skin Color

There are numerous studies of the association between skin color and IQ. Skin
color can be used as at least a weak proxy for racial admixture. We can ask
whether lighter, presumably more European, skin is associated with higher IQ. Of
course, if it were, this would constitute only modest support for the genetic
hypothesis because there would be valid grounds for assuming that more social
and economic advantages accrued to people with relatively light skin than to
people with relatively dark skin and that these advantages would be reflected in
higher IQs. In fact, however, the correlation between lightness of skin and IQ,
averaged over a large number of studies reviewed by Shuey (1966), is in the
vicinity of .10. The average correlation between IQ and judged “Negroidness” of
features is even lower.


Self-Reports of European Ancestry


Another way to determine the genetic origins of the Black–White difference is to examine the tails of the distribution of Black IQ. We can ask whether Blacks having a significant degree of European heritage are more likely to have high IQ scores. The extreme high-end tail of the IQ distribution should be especially telling, because on the hereditarian theory one would expect people at the tail to be particularly likely to have substantial European ancestry. Jenkins (1936) identified 63 children in a sample of Black Chicago schoolchildren with IQs of 125 or above, and 28 with IQs of 140 or above. Degree of European ancestry was assessed on the basis of self-reports about parents and grandparents. Children with IQs of 125 or above, as well as those with IQs of 140 or above, were slightly less likely to have substantial European ancestry than was estimated to be characteristic of the U.S. Black population as a whole at the time. The results are consistent with a model of zero genetic contribution to the Black–White gap. Rushton and Jensen do not mention this study.


Children in Postwar Germany Born to Black and White American Soldiers

Eyferth (1961) examined the IQs of several hundred German children fathered
by Black GIs during the post-1945 occupation and compared them with the
IQs of children fathered by White GIs. The children of the Black GIs had an
average IQ of 96.5. The children of the White GIs had an average IQ of 97.
Because the (phenotypic) Black–White gap in the military was similar to that for
the U.S. population, these data imply that the Black–White gap in the U.S.
population as a whole is not genetic, even in part (Flynn, 1980, pp. 87–88). The
results seem particularly telling because it seems highly likely that environmental
conditions were inferior for Black children.

How do Rushton and Jensen (2005) treat this study, so telling on the face of
it? They give it only two sentences of description and then proceed to critique it
on two main grounds. First, 20% to 25% of the “Black” fathers were North
African. But one would have to assume preposterously high IQ scores on the part
of the North African portion of the Black population to make up for the substantial
difference between offspring of Blacks and Whites predicted by their hereditarian
theory. Second, Rushton and Jensen assume that Black soldiers were more
rigorously selected than Whites and so might have had IQs nearly as high as those
of the White soldiers. Blacks in the military did indeed have higher IQs than did
Blacks in the general population, but the same was true of White soldiers
compared with the general White population. Flynn (1980) has argued that the
evidence indicates that the gap in IQ between Black and White soldiers was the
same as that in the U.S. population at large.


Mixed-Race Children Born to Either a Black or a White Mother


If the Black–White IQ gap is largely hereditary, then children having one
Black and one White parent should have the same IQ on average, regardless of
which parent is Black. But if one assumes that mothers are particularly important
to the intellectual socialization of their children and if the socialization practices
of Whites are more favorable to IQ development than those of Black mothers,
then children of White mothers and Black fathers should have higher IQs than
children of Black mothers and White fathers. This could of course not have a
plausible genetic explanation. In fact, it emerges that children of White mothers
and Black fathers have IQs 9 points higher than children with Black mothers and
White fathers (Willerman, Naylor, & Myrianthopoulos, 1974). This result in itself
suggests that most of the Black–White IQ gap is environmental in origin. But
because mothers are not the only environmental influence on the child’s IQ, the
9-point difference might be regarded as a very conservative estimate of the
environmental contribution to the gap.


What do Rushton and Jensen (2005) have to say about this study? Because the
White mother–Black father pairs averaged 1 year more of education than the
Black mother–White father pairs, they conclude the study is uninterpretable! Of
course, there can be no basis for assuming that 1-year’s difference in education on
the part of the parents could possibly translate into an expected 9 IQ point
difference for the children.

Studies Measuring European Ancestry Through Blood Group Indicators

Different races have different frequencies of various blood groups. If the
hereditarian model is correct, Blacks having more blood groups characteristic of
Europeans should have higher IQs. But Sandra Scarr and her colleagues (Scarr,
Pakstis, Katz, & Barker, 1977) found that the correlation between IQ and
“European” heritage among Blacks as measured by blood groups was only .05 in
a sample of 144 Black adolescent twin pairs. They found a typical correlation of
.15 between skin color and IQ, which suggests that the comparable correlations
between skin color and IQ in other studies are due not to more European genes on
the part of light-skinned Blacks but to social and economic advantages accruing
to individuals with lighter skin.

Another blood-group study, by Loehlin, Vandenberg, and Osborne (1973),
also examined the association between Europeanness and IQ in a sample of
Blacks. In this study, the estimated Europeanness of blood groups (rather than the
Europeanness of individuals, estimated from their blood groups) was correlated
with IQ in two small samples of Blacks (Loehlin et al., 1973). A .01 correlation
between IQ and the extent to which blood group genes were more characteristic
of European than African populations was found. In another small sample, they
found a nonsignificant, –.38 correlation, such that blood groups associated with
Europeanness predicted lower IQ scores.

How do Rushton and Jensen (2005) deal with these data, so apparently
damning of an even partially hereditary model? They report that “these studies
failed to choose genetic markers with large allele frequency differences between
Africans and Europeans” (p. 262). Of course, on the hereditarian hypothesis, the
markers would have to have been worthless to yield a zero difference between the
populations studied.

Rushton and Jensen (2005) add only a few studies to the list above concerned
with racial admixture, and those have extremely weak findings, poor methodology,
tangential relevance, or a combination of the three. For example, they cite
one study by Lynn (2002), which found a correlation of .17 between self-report
of skin color as “very dark,” “dark brown,” “light brown,” or “very light” and a
10-word vocabulary test score. Another study, by Rowe (2002), is merely yet
another showing that Blacks have lower IQ scores than Whites. Still other studies
ask us to believe that average IQ scores of 70 (in the retarded range) for samples
of Africans and for the Black children in a particular Georgia county could
possibly be an accurate reflection of genotypic IQ in pure African populations.
This would mean that an individual 2 standard deviations from the mean would
only manage to reach an IQ of 100, which is average for Western White
populations.

Rushton and Jensen (2005) end the empirical part of their article with a
scorecard. The scorecard results: hereditarian model (
); culture-only model (0).
But any sensible reading of the directly relevant research would have to
conclude that there is no support whatever in these studies for an even
partially hereditarian model. On the contrary, the converging methodologies
provide strong evidence that the genetic contribution to the Black–White IQ
gap is close to zero and do not even suggest a direction for any possible
genetic contribution.

Source: HEREDITY, ENVIRONMENT, AND RACE DIFFERENCES IN IQ A Commentary on Rushton and Jensen (2005) Psychology, Public Policy, and Law 2005, Vol. 11, No. 2, 302–310

 

Intelligence tests themselves may be flawed. These tests show differences between races, and Asians tend to score higher than Europeans.

 

Many of you have referred to a large response to Racism by repeating "The Bell Curve," Phillipe Rushton, the new Nicolas Wade race book with the same old Pioneer Fund racist logic and badly put together "scientific racism." Your story is very old and has been repeated and rebuffed by real human biologists and anthropologists. Of course, most of the critiques of my book, "The Myth of Race" have not bothered to read the book or many of the other books that I have referred to (or many other good scientific book outside of scientific racism). "Culture of Critique" is full of this garbage and I have dealt with, or refer to someone who has dealt with, all of the critiques in this little nutation. The problem that many of the critics of my book have is that you are already prejudice -- you have feelings that make you look for things that make your prejudice more meaningful. However, in the end what does this prejudice do for you and for "humans" generally? It makes you hate human variation, hate other people, and makes more trouble than it is worth. Think about the prejudice that you have and how it makes you feel and them think of the prejudice someone whose ancestors where broken from their families and brought to the U.S. as slaves, and then are mainly kept in lower classes throughout modern history. How angry would they be? How would you feel if you were an young adult male, brought up poor, unable to get a job, and treated poorly by the police? How would you like that. Some of you will say: Oh, I could easily, first go to school, and then get a job! Well, what you might think is easy is not. Put a different cultural background in your own life and try to live with it. You do not realize how much your cultural background relates to how you behave. If you did, you would not be so prejudice! It would be good to get some good questions from people who have really read my book and want to learn more about the history of race in the U.S. and Europe.

 

*facepalm*

 

After a large amount of mixing over time, there may not be much of a correlation left between those markers of distant european ancestry and genes that could lead to a higher IQ.

Let me give you an example. Suppose you have a jar that contains a mix of red and white gumballs. And you have ten jars of blue gumballs. You take a handful of gumballs from the white/red jar and drop them into 5 of the blue gumball jars each. Now looking at the jars which contain blue gumballs, there's obviously a correlation between red gumballs and white gumballs. If a jar contains a red gumball, it is very likely to contain some white gumballs also. While if it does not contain a red gumball, it is unlikely to contain any white gumballs. Simple so far.

Now, suppose you take these 10 jars of blue gumballs, and mix them into a giant vat of blue gumballs. Then you pour it back into 100 jars. Well, now many of these jars will contain only one 1 or 2 white or red gumballs. There will no longer be such a big correlation. It might contain two red gumballs, but that does not mean there will be any white gumballs in the same jar.

And skin color is a terrible indicator of how much european ancestry an African American has. It's just how the genes work. An African American with a half white father and a white grandmother, and probably plenty more additional european ancestry far back, can still appear much darker than an African American who only has two great grandmothers (on different sides), but who's ancestors are otherwise All-Black.

 

We know that's not true though from recent DNA studies. African-Americans are on average about 20% European. In some areas they are upwards to 30% European. Individual African-Americans can range from 100% African genetically to being mostly European genetically. The genetic impact on the African-American gene pool is still very strong. Your gumball analogy would be more appropriate if African-Americans had mixed back in to the African gene pool. Over time the European ancestry would be diluted but that didn't happen. Mixed Blacks mixing with mixed Blacks have created different shades of Black people in America having the European-derived ancestry in varying quantities depending on the individual and the region.

Nisbett did admit that skin color was a weak proxy for racial admixture for the very reason you site. Still lighter-skinned Blacks tend to be more genetically European than dark-skinned Blacks so this indicator is not useless. The fact that 5 different types of tests all confirm the same results is significant. Modern DNA testing would be better than any of these studies but their finding is still valid science.

 

I am enjoying reading your book so far. I think many of the racists are too stuck in their ways to be open-minded to reading your book. But this thread is a good place for you to answer questions about the subject matter and debate some of the challenges to your position showing to them that your book is worth reading.

 

that was the posters point, and black skin is not part of the white race, white skin is not part of the black race, ect....

children are young people, the elderly are old people... the list goes on.....

these are just groupings within the human race that describe differences, nothing more

.

 

if we used selective breeding, we could create black skinned Euro-Caucasians within a few generations.

we could also create white skinned sub-Saharan Africans.

- - - Updated - - -

in fact, based on the genetic & physical diversity of sub-Saharan Africans, we could create people through selective breeding that looked JUST like Europeans.

 

Bob, I'm curious what you think the reason for Black regression of IQ from children in enriched learning environments to adults whose IQ drops back to the Black average? Eg., a Black child in a head start program may have an IQ of 100 but as an adult outside the enriched learning environment their IQ drops to the Black average as if they had never attended better schooling.

Also, what's your view of Black and White parents with the same IQ - of, say, 115 - having, on average, children whose IQ is closer to their respective race? In other words, why would Black children have lower IQ than White children if all the children have parents with the same (high) IQ?

 

What is this "race" you refer to? All you're describing is skin tone. Yes, people with white skin tone wont have children with black skin tone (as far as I'm aware), but that doesnt create a "race" of people in the form of those who have white skin. That's like saying redheads are a race. The whole idea of race collapses in on itself, as Sussman pointed out earlier.

But race is not readily identifiable in terms of biology. What you have basically said is 'race exists merely as superficial distinction between select characteristics.' If that is the case, its really a redundant term.

 

The existence of allelic clines and the observation that the bulk of human variation is continuously distributed, has led some scientists to conclude that any categorization schema attempting to partition that variation meaningfully will necessarily create artificial truncations. (Kittles & Weiss 2003). It is for this reason, Reanne Frank argues, that attempts to allocate individuals into ancestry groupings based on genetic information have yielded varying results that are highly dependent on methodological design.[8] Serre and Pääbo (2004) make a similar claim: The absence of strong continental clustering in the human gene pool is of practical importance. It has recently been claimed that “the greatest genetic structure that exists in the human population occurs at the racial level” (Risch et al. 2002). Our results show that this is not the case, and we see no reason to assume that “races” represent any units of relevance for understanding human genetic history.

In a response to Serre and Pääbo (2004), Rosenberg et al. (2005) make three relevant observations. Firstly they maintain that their clustering analysis is robust. Secondly they agree with Serre and Pääbo that membership of multiple clusters can be interpreted as evidence for clinality (isolation by distance), though they also comment that this may also be due to admixture between neighbouring groups (small island model). Thirdly they comment that evidence of clusterdness is not evidence for any concepts of "biological race".[9] Risch et al. (2002) state that "two Caucasians are more similar to each other genetically than a Caucasian and an Asian", but Bamshad et al. (2004)[10] used the same data set as Rosenberg et al. (2002) to show that Europeans are more similar to Asians 38% of the time than they are to other Europeans when only 377 microsatellite markers are analysed.

http://en.wikipedia.org/wiki/Human_genetic_clustering

 

race imo is nothing more then a descriptor as I just said, for example saying the black race means you have black skin, nothing more

some want race to mean more, but it doesn't, Obama's mother was white, but his skin is black, people would say he is part of the black race.. but that is just because of his skin color, nothing else

it sounds to me like your agreeing with me.....

.

 

We're in agreement.

 

I was just reading Sussman's book after downloading it onto my Kindle app.

It's not so much a detailed rebuttal of scientific racialism itself (though it references many of those written by other authors) as it is a history of the movement's development. The whole eugenics movement of the early 20th century, and its proponents' conflict with Boasian anthropology, receives particular emphasis. I must admit I was personally saddened to learn that one of the leading eugenicists was Henry Fairfield Osborn, the guy who named Tyrannosaurus rex (my favorite animal of all time).

I did think the critiques of twin study methodology were eye-opening, especially since I still hear studies like that being cited to support all kinds of weird uber-hereditarian wackiness.

 

As the great Dr. Sussman has fled the scene, I'll take up the argument with you. The first issue you must deal with is racism. Once this core issue is addressed, then we can move on.

Racism:
the belief that all members of each race possess characteristics or abilities specific to that race, especially so as to distinguish it as inferior or superior to another race or races,
prejudice, discrimination, or antagonism directed against someone of a different race based on the belief that one's own race is superior.

So if one ignores reality, one will not be "racist" as science-based basic human observation leads to the undeniable facts that certain races are inherentily better than others.

Every single world record marathon runner has been of Black ancestry over the last 16 years, and the last six of these 10 record holders have been of East African (Kenyan and Ethiopan) ancestry.
http://en.wikipedia.org/wiki/Marathon_world_record_progression

Men's world record long jump records have been dominated by Blacks over the last 40 years.

Also, Black and very dark skin have superior UV protection---up to 70 times better than White's:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2671032/

However "small" the genome of different "races" are, they do produce significant differences, anyone who believes any of the above facts is a racist. Sussman spoke of those who didn't share his political bias as being no more enlightened than "flat earthers." I say that you, Sussman and anyone else who ignores basic science and think that there are no significant difference in IQ between groups of people are like the "flat earthers."

Just as racial traits give obvious advantages in so many areas, the brain behaves in the very way, as it does not exisist in its own universe outside the human body. Neural and ocular diseases such as Sickle Cell trait, Glaucoma, and Alzheimer's have strong inherited patterns along racial lines. To think that intelligence does not operate by the same laws as the rest of the body, and has some unlimited potential, or is primartly shaped by environmental events---is almost laughable.

http://www.cbsnews.com/news/alzheim...-increased-disease-risk-in-african-americans/

Of couse the Minnestota Transracial Adoption Study has not been duplicated in recent times. And even if it was, the same silly arguments will be made that the Blacks and others "didn't have the best enviroment, love, nurturing, etc." until they were adopted, and this imagined shortfall can never be amended. I think these theories that Nisbett and Sussman use are themselves "racist" and politically biased.

As I suggested, to end the argument once and for, there only needs to be the proof that genetic differences do lead to differences in intelligence. Therefore only fit sujects in their twenties who have been raised in good health and good family circumstances should be used. A genetic DNA profile will show the precise "racial" pedigree of each subject, an MRI of the brain structure,and a digit span test; the best, non-biased, non-cultural test of memory (IQ). Until the taboos that exsist among Psycholgists and Anthropologists are lifted, these tests will not be done.

Finally, if you and Sussman were to be believed, then geniuses and those with natural gifts could not exsist. Only the quality of the parents and teachers would matter. I wonder how Mozart could write music at age 5 and teach himself to play the violin? Anyone should be able to do that. The real world proves that a modern complex society needs those with an average IQ of 100 or better to thrive. The IQ needed to invent rockets and computers is far above that what is needed to track animals, pick berries and find watering holes.

 

I have never said that innate genius does not exist. Intelligence is heritable to a significant degree between individuals and families but not unevenly distributed across geographic populations.