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Genes' Sway Over IQ May Vary With Class
Study: Poor More Affected by Environment

By Rick Weiss
Washington Post Staff Writer
Tuesday, September 2, 2003; Page A01


Back-to-school pop quiz: Why do poor children, and especially black poor children, score lower on average than their middle-class and white counterparts on IQ tests and other measures of cognitive performance?

It is an old and politically sensitive question, and one that has long fueled claims of racism. As highlighted in the controversial 1994 book "The Bell Curve," studies have repeatedly found that people's genes -- and not their environment -- explain most of the differences in IQ among individuals. That has led a few scholars to advance the hotly disputed notion that minorities' lower scores are evidence of genetic inferiority.

Now a groundbreaking study of the interaction among genes, environment and IQ finds that the influence of genes on intelligence is dependent on class. Genes do explain the vast majority of IQ differences among children in wealthier families, the new work shows. But environmental factors -- not genetic deficits -- explain IQ differences among poor minorities.

The results suggest that early childhood assistance programs such as Head Start can help the poor and are worthy of public support. They also suggest that middle-class and wealthy parents need not feel guilty if they don't purchase the latest Lamaze mobile or other expensive gadgets that are pitched as being so important to their children's development.

"How many books are in the home and how good the teacher is may be questions to consider for a middle-class child, but those questions are much more important when we're talking about children raised in abject poverty," said lead researcher Eric Turkheimer, a psychologist at the University of Virginia.

The work, to be published in the November issue of the journal Psychological Science, is part of a new wave of research that embraces a more dynamic view of the relationship between genes and environment. Although older research treated nature and nurture as largely independent and additive factors, and saw people as the sum of their genetic endowments and environmental experiences, the emerging view allows that genes can influence the impact of experiences and experiences can influence the "expression," or activity levels, of genes.

In Turkheimer's study, the impact of genes on IQ varied depending on a child's socioeconomic status (SES), a sociological measure that includes household income and other elements of class and social status.

Until recently, Turkheimer and others said, research had indicated that the "heritability" of IQ -- that is, the degree to which genes can explain the differences in IQ scores -- completely dominated environmental influences. That led some to call into question the value of programs such as Head Start, which are based on the assumption that by improving the childhood environment through extra attention, nutrition and care, a child's intellectual future could be improved.

But it turned out that virtually all those studies on the heritability of IQ had been done on middle-class and wealthy families. Only when Turkheimer tested that assumption in a population of poor and mostly black children did it become clear that, in fact, the influence of genes on IQ was significantly lower in conditions of poverty, where environmental deficits overwhelm genetic potential.

"This paper shows how relevant social class is" to children's ability to reach their genetic potential, said Sandra Scarr, a professor emerita of psychology now living in Hawaii, who did seminal work in behavioral genetics at the University of Virginia.

Specifically, the heritability of IQ at the low end of the wealth spectrum was just 0.10 on a scale of zero to one, while it was 0.72 for families of high socioeconomic status. Conversely, the importance of environmental influences on IQ was four times stronger in the poorest families than in the higher status families.

"This says that above a certain level, where you have a wide array of opportunities, it doesn't get much better" by adding environmental enhancements, Scarr said. "But below a certain level, additional opportunities can have big impacts."

The principle is straightforward and has long been recognized in plants and other simpler organisms. In one famous example, often repeated by evolutionary biologist Richard Lewontin, two genetically identical seeds of corn, planted in very different soil conditions, will grow to very different heights.

Some social psychologists and behavior geneticists have hypothesized that the same must hold true for the relationships linking human genes, socioeconomic status and IQ. Like corn in depleted soil, the thinking goes, minorities and the poor (two categories with so much overlap that researchers find it difficult to tease apart their effects) perform worse not because of their genes but because they are raised in an environment lacking in resources and poisoned by racist attitudes.

"It's a hypothesis that makes a great deal of sense on its face, but has been difficult to study," Scarr said. Difficult, she said, because the best way to study the relative contributions of genes and environment to a human trait is to conduct studies on twins or, in some cases, adopted children. And almost all the twins and adoptees who have been available for study over the years have come from middle-class or higher-class families.

Turkheimer got around that shortage by tapping into data from the now defunct National Collaborative Perinatal Project, which started in the late 1960s. That study, funded by the National Institutes of Health, enrolled nearly 50,000 pregnant women, most of them black and quite poor, in several major U.S. cities. Researchers collected loads of data on the families and gave the children IQ tests seven years later.

Although the study was not designed to study twins, it was so big that many twins were born -- 623 pairs, to be exact, 320 of whom were successfully located by the original researchers and tested for IQ at age 7 in the 1970s. By culling through those test scores and the data on the families' socioeconomic status, Turkheimer was able to conduct one of the first analyses of the role of genes in IQ among the poor.

Twin studies are useful because there are two kinds of twins -- identical twins, which are 100 percent genetically identical, and fraternal twins, which (like other siblings) are 50 percent genetically identical.

Whether twins are identical or fraternal, they share identical prenatal conditions in the womb as they gestate together and they are raised in virtually identical environmental circumstances. That cuts out a major share of environmental differences between the two in any pair.

So when scientists find traits that are more commonly shared between identical twins than between fraternal twins, that suggests the trait is one with a strong genetic basis.

Taking advantage not only of that unique population of children but also of new statistical methods that allowed them to measure complex interactions, Turkheimer and his colleagues -- including University of Minnesota behavioral geneticist Irving Gottesman -- found that the lower a child's socioeconomic status, the less impact genetic inheritance had on IQ.

"It gets away from the pessimistic conclusion that high heritability means you're wasting your money on Head Start," Gottesman said. He suggested that other interventions, including improved prenatal care, would raise IQ even more.

And although IQ remains a controversial measure, criticized by some as being racially biased in itself and a poor reflection of intelligence in the highest sense of the word, Gottesman and others noted that it remains the best predictor today of social and economic success in U.S. society.

Robert Plomin, a behavioral geneticist with the Institute of Psychiatry at King's College of London, who has been seeking genes linked specifically to intelligence, said the results do not undermine the importance of genes.

"In study after study, the evidence is overwhelming that there is a substantial genetic input to IQ," Plomin said. "This doesn't contradict that, but it leads to an interesting possibility that although it's true for the [middle- and upper-class] populations that have been studied . . . it's not going to mean much if you're in an impoverished environment."

Plomin said his own unpublished work involving 4,000 pairs of twins has not produced the same results as Turkheimer's. "We've looked at this for families unemployed, on state support and living in subsidized housing, and we still don't find it, even at that low level" of socioeconomic status, he said.

But, he said, that may simply mean that his population was not as poor as Turkheimer's -- or was benefiting from Britain's superior social safety net.

In fact, the families in Turkheimer's study were very poor, with a median income of $17,000 a year in 1997 dollars. One in five of the mothers was younger than 21, one-third of them were on public assistance, and more than one-third did not have a husband.

Marcus Feldman, a population geneticist at Stanford University who has studied gene-environment interactions, said the next big challenge is to find out what it is about socioeconomic status -- a measure that includes not only income but also parental education and occupational status -- that contributes to IQ, so social programs can more effectively boost those factors.

"SES is a surrogate for something that deserves further study," Feldman said. "A paper like this reemphasizes the importance of psychology and educational psychology and draws us somewhat away from genetics and back into the importance of the social sciences for understanding IQ. This says to me, let's spend the money and find out what it is about SES that makes the difference."



© 2003 The Washington Post Company
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You know, this really pisses me off!!!!

THIS IS NOT NEWS!!!

We, the United States, the Environmental Protection Agency, the National Institutes of Health, the Centers for Disease Control, the environmental agency of every State in the Union has know this for at least 25 years, that I know personally.

"Marcus Feldman, a population geneticist at Stanford University who has studied gene-environment interactions, said the next big challenge is to find out what it is about socioeconomic status -- a measure that includes not only income but also parental education and occupational status -- that contributes to IQ, so social programs can more effectively boost those factors.

"SES is a surrogate for something that deserves further study," Feldman said. "A paper like this reemphasizes the importance of psychology and educational psychology and draws us somewhat away from genetics and back into the importance of the social sciences for understanding IQ. This says to me, let's spend the money and find out what it is about SES that makes the difference."

What unmitigated, absolute bullshit!!

The man said, "We need to find out what it is about socioeconomic status that contributes to IQ so social programs can boost those factors. They have given "socioeconomic status" its own acronym SES. LOOK OUT NOW!!

This is all about money. There is no mystery. There is no great information gap. Society does things to those who are poor. Wherever and whenever there is a downside to a decision to be made in our environment, the downside goes to the poorer segment of our society.

This not hyperbole. I know this is true. Everyone knows its true. Including these jokers who are milking the government for money to "study" SES.

Puh leeeze!!!

This is a perfect example of creating a problem. Do a study, tell the lie, get a couple of equally duplicitous PhDs to swore to it, sign it with a PhD, and you get money. Especially if its about the poor (read "black").

PEACE

Jim Chester

You are who you say you are. Your children are who you say you are.

[This message was edited by James Wesley Chester on September 02, 2003 at 01:29 PM.]


[This message was edited by James Wesley Chester on September 02, 2003 at 01:32 PM.]
Seeing as to how everybody's gene pool's all mixed up into one humongous hodge-podge of genes, because of all the lyin' and denyin' on sexual indescretions. Save the money and spend it on mandatory DNA tests. That will make all this black, white, polka-dot jazz a moot point. Maybe then, everyone can work on being HUMAN, in a good way for a change for those that survive the TRUTH.
I came back to this because all I really did was "get off a rant" about something that has been an irritant for years. Heat, no light.

The study in the effect of environment on IQ may have been done by "innocents." But the effect of environment on brain development is known, and in many instances quantitative detail.

What is so irritating about this is a pretense of "not knowing" has always arisen when the issue is bought up regarding African American children. Or any other non-European poor. The challenge would always be made, "What evidence of such drastic effects do you have?" "We know of no such reputable studies." Yada, Yada.

But they know heavy metals in the environment, air, water, food, soil, paint, pipes, etc no to mention malnutrition, bad medicine, bad practice of medicine all have direct and frequently cumulative effect.

It's enough to piss one off.

PEACE

Jim Chester

You are who you say you are. Your children are who you say you are.
I'm glad someone has brought this up. There was recently an expose on lead poisoning and poor communities on a local TV station where I live. It was horrible. A normal little girl got lead poisoned and now she is physically and mentally handicapped. It was also pointed out that now smaller amounts of lead constitute lead poisoning and can have more of a detrimental affect.
Poor neighborhoods are usually older neighborhoods that were built before lead regulation, especially in the Northeast.

Our people have made the mistake of confusing the methods with the objectives. As long as we agree on objectives, we should never fall out with each other just because we believe in different methods, or tactics, or strategy. We have to keep in mind at all times that we are not fighting for separation. We are fighting for recognition as free humans in this society
Malcolm X, 1965
Usually, what they do not tell you in studies like this is that they are comparing black students from poor backgrounds to white students from at least middle class backgrouds; they usually fail to mention that most students actually score about the same from the same socio-economic backgrounds regardless of race. Human "I.Q." could never be really measured because it has to include intelligence potential and there is not a way to truly predict the potential of the human mind. Usually the differences in levels between black/white students is the difference in minor cultural norms/practices that do not have anything to do with intelligence, yet are counted as it does. What I.Q. usually boils down to is how much you have been actually been taught of knowledge of which you did not come to a conclusion on, but how much you remember of things already figured out by someone else. How well students do on tests and in education also depends on the students interest and desire to learn. If a student's interest in learning is interfered with by any more imminent concerns, it will affect how much the student will learn and how much the student desires to learn. It's more like they are measuring students' psychological prioriortizing of what should be or is their most imminent interests in life at the time, and counting any lack of interest to learn or lack of a student making it a number one priority as a lack of ability to learn, to know, to do, or to understand. So, what exactly are I.Q. tests, a measure of a person's ability to learn or understand or a talley of knowledge the person already memorized?
Sunnubian: I agree. Many of these kinds of reports are statistical trickery. I became convenience of this when I was first required to take such tests. And was then required to take the test a second time when they didn't believe my score. I know I wasn't brightest candle on my block. So why so "to do" about this? Well, it turned out there were things that had to happen if I score at a certain level. They didn't want me to have those things.

Yssys: You will be even more shocked to know that this was going on 30 years ago. That's why I get so ticked. I had a conversation with the Centers for Disease Control trying to determine the action level for lead in the blood of children under 12 years. The action number was 30 units. I had kids with 40, 50, 60, and one with 75 units. CDC said the number should be 20 units and in the next ten years would probably be dropped to 15 units. It may now be as low as 10 units.

It was known then that the primary cause was environmental. That is the primary reason lead was removed from gasoline. Can you picture where expressways cut through cities. That was no accident. That is why lead was taken out of paints. Beyond the impact of lead paint in homes, can you picture highway maintenance crews painting bridges, etc in these neighborhoods. That was/is no accident.

This has been going on for decades.

By the way, there is book currently on the market entitled: "Nature vs Nurture". It is excellent. It seems to be objective. It's on my list of books to get. I forget the author. He recently did a segment on C-SPAN's Book-TV.

PEACE

Jim Chester

You are who you say you are. Your children are who you say you are.

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