[extropy-chat] FWD (SK) After the Bell Curve

[Terry Colvin]

-----Forwarded Message-----
>
>July 23, 2006
>IDEA LAB
>After the Bell Curve
>
>By DAVID L. KIRP
>
>http://www.nytimes.com/2006/07/23/magazine/23wwln_idealab.html? 
>pagewanted=print
>
>When it comes to explaining the roots of intelligence, the fight  
>between partisans of the gene and partisans of the environment is  
>ancient and fierce. Each side challenges the other?s intellectual  
>bona fides and political agendas. What is at stake is not just the  
>definition of good science but also the meaning of the just society.  
>The nurture crowd is predisposed to revive the War on Poverty, while  
>the hereditarians typically embrace a Social Darwinist perspective.
>A century?s worth of quantitative-genetics literature concludes that  
>a person?s I.Q. is remarkably stable and that about three-quarters of  
>I.Q. differences between individuals are attributable to heredity.  
>This is how I.Q. is widely understood ? as being mainly ?in the  
>genes? ? and that understanding has been used as a rationale for  
>doing nothing about seemingly intractable social problems like the  
>black-white school-achievement gap and the widening income disparity.  
>If nature disposes, the argument goes, there is little to be gained  
>by intervening. In their 1994 best seller, ?The Bell Curve,? Richard  
>Herrnstein and Charles Murray relied on this research to argue that  
>the United States is a genetic meritocracy and to urge an end to  
>affirmative action. Since there is no way to significantly boost  
>I.Q., prominent geneticists like Arthur Jensen of Berkeley have  
>contended, compensatory education is a bad bet.
>
>But what if the supposed opposition between heredity and environment  
>is altogether misleading? A new generation of studies shows that  
>genes and environment don?t occupy separate spheres ? that much of  
>what is labeled ?hereditary? becomes meaningful only in the context  
>of experience. ?It doesn?t really matter whether the heritability of  
>I.Q. is this particular figure or that one,? says Sir Michael Rutter  
>of the University of London. ?Changing the environment can still make  
>an enormous difference.? If heredity defines the limits of  
>intelligence, the research shows, experience largely determines  
>whether those limits will be reached. And if this is so, the  
>prospects for remedying social inequalities may be better than we  
>thought.
>
>
>
>When quantitative geneticists estimate the heritability of I.Q., they  
>are generally relying on studies of twins. Identical twins are in  
>effect clones who share all their genes; fraternal twins are siblings  
>born together ? just half of their genes are identical. If heredity  
>explains most of the difference in intelligence, the logic goes, the  
>I.Q. scores of identical twins will be far more similar than the  
>I.Q.?s of fraternal twins. And this is what the research has  
>typically shown. Only when children have spent their earliest years  
>in the most wretched of circumstances, as in the infamous case of the  
>Romanian orphans, treated like animals during the misrule of Nicolae  
>Ceausescu, has it been thought that the environment makes a notable  
>difference. Otherwise, genes rule.
>
>Then along came Eric Turkheimer to shake things up. Turkheimer, a  
>psychology professor at the University of Virginia, is the kind of  
>irreverent academic who gives his papers user-friendly titles like  
>?Spinach and Ice Cream? and ?Mobiles.? He also has a reputation as a  
>methodologist?s methodologist. In combing through the research, he  
>noticed that the twins being studied had middle-class backgrounds.  
>The explanation was simple ? poor people don?t volunteer for research  
>projects ? but he wondered whether this omission mattered.
>
>Together with several colleagues, Turkheimer searched for data on  
>twins from a wider range of families. He found what he needed in a  
>sample from the 1970?s of more than 50,000 American infants, many  
>from poor families, who had taken I.Q. tests at age 7. In a widely- 
>discussed 2003 article, he found that, as anticipated, virtually all  
>the variation in I.Q. scores for twins in the sample with wealthy  
>parents can be attributed to genetics. The big surprise is among the  
>poorest families. Contrary to what you might expect, for those  
>children, the I.Q.?s of identical twins vary just as much as the  
>I.Q.?s of fraternal twins. The impact of growing up impoverished  
>overwhelms these children?s genetic capacities. In other words, home  
>life is the critical factor for youngsters at the bottom of the  
>economic barrel. ?If you have a chaotic environment, kids? genetic  
>potential doesn?t have a chance to be expressed,? Turkheimer  
>explains. ?Well-off families can provide the mental stimulation  
>needed for genes to build the brain circuitry for intelligence.?
>
>This provocative finding was confirmed in a study published last  
>year. An analysis of the reading ability of middle-aged twins showed  
>that even half a century after childhood, family background still has  
>a big effect ? but only for children who grew up poor. Meanwhile,  
>Turkheimer is studying a sample of twins who took the National Merit  
>Scholarship exam, and the results are the same. Although these are  
>the academic elite, who mostly come from well-off homes, variations  
>in family circumstances still matter: children in the wealthiest  
>households have the greatest opportunity to develop all their genetic  
>capacities. The better-off the family, the more a child?s genetic  
>potential is likely to be, as Turkheimer puts it, ?maxed out.?
>
>
>n seeking to understand the impact of nature and nurture on I.Q.,  
>researchers have also looked at adopted children. Consistent with the  
>proposition that intelligence is mainly inherited, these studies have  
>almost always found that adopted youngsters more closely resemble  
>their biological than their adoptive parents. Such findings have  
>supported the assumption that changing a child?s life circumstances  
>won?t alter the hard facts of nature.
>
>But researchers in France noted a shortcoming in these adoption  
>studies and set out to correct it. Since poor families rarely adopt,  
>those investigations have had to focus only on youngsters placed in  
>well-to-do homes. What?s more, because most adopted children come  
>from poor homes, almost nothing is known about adopted youngsters  
>whose biological parents are well-off.
>
>What happens in these rare instances of riches-to-rags adoption? To  
>answer that question, two psychologists, Christiane Capron and Michel  
>Duyme, combed through thousands of records from French public and  
>private adoption agencies. ?It was slow, dusty work,? Duyme recalls.  
>Their natural experiment mimics animal studies in which, for  
>instance, a newborn rhesus monkey is taken from its nurturing  
>biological mother and handed over to an uncaring foster mother. The  
>findings are also consistent: how genes are expressed depends on the  
>social context.
>
>Regardless of whether the adopting families were rich or poor, Capron  
>and Duyme learned, children whose biological parents were well-off  
>had I.Q. scores averaging 16 points higher than those from working- 
>class parents. Yet what is really remarkable is how big a difference  
>the adopting families? backgrounds made all the same. The average  
>I.Q. of children from well-to-do parents who were placed with  
>families from the same social stratum was 119.6. But when such  
>infants were adopted by poor families, their average I.Q. was 107.5 ?  
>12 points lower. The same holds true for children born into  
>impoverished families: youngsters adopted by parents of similarly  
>modest means had average I.Q.?s of 92.4, while the I.Q.?s of those  
>placed with well-off parents averaged 103.6. These studies confirm  
>that environment matters ? the only, and crucial, difference between  
>these children is the lives they have led.
>
>A later study of French youngsters adopted between the ages of 4 and  
>6 shows the continuing interplay of nature and nurture. Those  
>children had little going for them. Their I.Q.?s averaged 77, putting  
>them near retardation. Most were abused or neglected as infants, then  
>shunted from one foster home or institution to the next.
>
>Nine years later, they retook the I.Q. tests, and contrary to the  
>conventional belief that I.Q. is essentially stable, all of them did  
>better. The amount they improved was directly related to the adopting  
>family?s status. Children adopted by farmers and laborers had average  
>I.Q. scores of 85.5; those placed with middle-class families had  
>average scores of 92. The average I.Q. scores of youngsters placed in  
>well-to-do homes climbed more than 20 points, to 98 ? a jump from  
>borderline retardation to a whisker below average. That is a huge  
>difference ? a person with an I.Q. of 77 couldn?t explain the rules  
>of baseball, while an individual with a 98 I.Q. could actually manage  
>a baseball team ? and it can only be explained by pointing to  
>variations in family circumstances.
>
>Taken together, these studies show that the issue has changed: it is  
>no longer a matter of whether the environment matters but when and  
>how it matters. And poverty, quite clearly, is an important part of  
>the answer.
>
>That is not to say that an affluent home is necessarily a good home.  
>A family?s social standing is only a proxy for the time and energy  
>needed to keep a youngster mentally engaged, as well as the social  
>capital that helps steer a child to success. There are, of course,  
>many affluent parents who do a bad job of raising their children, and  
>many poor families who nurture their kids with care and intelligence.  
>On average, though, well-off households have the resources needed to  
>provide better settings for the fullest development of a child?s  
>natural abilities. In ?Meaningful Differences in the Everyday  
>Experience of Young American Children,? the University of Kansas  
>psychologists Betty Hart and Todd Risley find that by the time they  
>are 4 years old, children growing up in poor families have typically  
>heard a total of 32 million fewer spoken words than those whose  
>parents are professionals. That language gap translates directly into  
>stunted academic trajectories.
>
>Is there a way to reduce such gaps? In recent years, the case for  
>investing in early-childhood education has become stronger and  
>stronger. The federal Early Head Start program for infants and  
>toddlers is effective when it is well implemented ? in part because  
>it succeeds in getting parents more involved with their children.  
>Recent research also shows that one year of high-quality state  
>prekindergarten can give children as much as a seven-month advantage  
>in vocabulary; this, in turn, is a good predictor of how well they  
>will read when they are in primary school. As you would expect, poor  
>children benefit the most, especially when they are in classes with  
>middle-class youngsters.
>
>The push for universal preschool is not a red-state-blue-state issue;  
>the pioneers in the area are Oklahoma and Georgia, not generally  
>known for social progressivism. And with the support of business  
>groups and prominent philanthropists like Susan Buffett, the daughter  
>of Warren Buffett, it may enter the national agenda. If it does, it  
>will be a small step toward a society in which not only the most  
>fortunate children will be able to ?max out? their potential.
>
>David L. Kirp, a professor of public policy at the University of  
>California at Berkeley, is writing a book about the universal  
>preschool movement.
>
>Copyright 2006 The New York Times Company
>