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#31
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IQ and what it means in adulthood
On Nov 10, 4:02 pm, Sarah Vaughan wrote:
Does anyone know of any good articles/studies on how well IQ scores in childhood correlate with success in adulthood, given all the inherent inaccuracies of the tests? I realise this is a pretty broad topic, but I know there are some well-informed people here, and the subject has come up for discussion on someone's blog so I'm interested in finding out more. Linda Gottfredson has studied how IQ predicts health and longevity and academic and career success, and her papers are available online at http://www.udel.edu/educ/gottfredson...nts/index.html . Here is an article discussing how IQ differences between siblings predict future income, illegitimate births, and divorce. Looking at siblings is a simple way to control for socioeconomic status of the parents. http://www.eugenics.net/papers/murray.html IQ Will Put You In Your Place By Charles Murray From the Sunday Times, UK, May 25 1997. A longer version of this article appears in the summer issue of The Public Interest. Imagine several hundred families which face few of the usual problems that plague modern society. Unemployment is zero. Illegitimacy is zero. Divorce is rare and occurs only after the children's most formative years. Poverty is absent - indeed, none of the families is anywhere near the poverty level. Many are affluent and all have enough income to live in decent neighbourhoods with good schools and a low crime rate. If you have the good fortune to come from such a background, you will expect a bright future for your children. You will certainly have provided them with all the advantages society has to offer. But suppose we follow the children of these families into adulthood. How will they actually fare? A few years ago the late Richard Herrnstein and I published a controversial book about IQ, The Bell Curve, in which we said that much would depend on IQ. On average, the bright children from such families will do well in life - and the dull children will do poorly. Unemployment, poverty and illegitimacy will be almost as great among the children from even these fortunate families as they are in society at large - not quite as great, because a positive family background does have some good effect, but almost, because IQ is such an important factor. "Nonsense!" said the critics. "Have the good luck to be born to the privileged and the doors of life will open to you - including doors that will let you get a good score in an IQ test. Have the bad luck to be born to a single mother struggling on the dole and you will be held down in many ways - including your IQ test score." The Bell Curve's purported relationships between IQ and success are spurious, they insisted: nurture trumps nature; environment matters more than upbringing. An arcane debate about statistical methods ensued. Then several American academics began using a powerful, simple way of testing who was right: instead of comparing individual children from different households, they compared sibling pairs with different IQs. How would brothers and sisters who were nurtured by the same parents, grew up in the same household and lived in the same neighbourhood, but had markedly different IQs, get on in life? The research bears out what parents of children with unequal abilities already know - that try as they might to make Johnny as bright as Sarah, it is difficult, and even impossible, to close the gap between them. A very large database in the United States contains information about several thousand sibling pairs who have been followed since 1979. To make the analysis as unambiguous as possible, I have limited my sample to brothers and sisters whose parents are in the top 75 per cent of American earners, with a family income in 1978 averaging £40,000 (in today's money). Families living in poverty, or even close to it, have been excluded. The parents in my sample also stayed together for at least the first seven years of the younger sibling's life. Each pair consists of one sibling with an IQ in the normal range of 90-110 ,a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the bright) or lower than 90, putting him in the bottom quartile (the dull). These constraints produced a sample of 710 pairs. How much difference did IQ make? Earned income is a good place to begin. In 1993, when we took our most recent look at them, members of the sample were aged 28-36. That year, the bright siblings earned almost double the average of the dull: £22,400 compared to £11,800. The normals were in the middle, averaging £16,800. These differences are sizeable in themselves. They translate into even more drastic differences at the extremes. Suppose we take a salary of £50,000 or more as a sign that someone is an economic success. A bright sibling was six-and-a-half times more likely to have reached that level than one of the dull. Or we may turn to the other extreme, poverty: the dull sibling was five times more likely to fall below the American poverty line than one of the bright. Equality of opportunity did not result in anything like equality of outcome. Another poverty statistic should also give egalitarians food for thought: despite being blessed by an abundance of opportunity, 16.3% of the dull siblings were below the poverty line in 1993. This was slightly higher than America's national poverty rate of 15.1%. Opportunity, clearly, isn't everything. In modern America, and also, I suspect, in modern Britain, it is better to be born smart and poor than rich and stupid. Another way of making this point is to look at education. It is often taken for granted that parents with money can make sure their children get a college education. The young people in our selected sample came from families that were overwhelmingly likely to support college enthusiastically and have the financial means to help. Yet while 56% of the bright obtained university degrees, this was achieved by only 21% of the normals and a minuscule 2% of the dulls. Parents will have been uniformly supportive, but children are not uniformly able. The higher prevalence of college degrees partly explains why the bright siblings made so much more money, but education is only part of the story. Even when the analysis is restricted to siblings who left school without going to college, the brights ended up in the more lucrative occupations that do not require a degree, becoming technicians, skilled craftsmen, or starting their own small businesses. The dull siblings were concentrated in menial jobs. The differences among the siblings go far beyond income. Marriage and children offer the most vivid example. Similar proportions of siblings married, whether normal, bright or dull - but the divorce rate was markedly higher among the dull than among the normal or bright, even after taking length of marriage into account. Demographers will find it gloomily interesting that the average age at which women had their first birth was almost four years younger for the dull siblings than for the bright ones, while the number of children born to dull women averaged 1.9, half a child more than for either the normal or the bright. Most striking of all were the different illegitimacy rates. Of all the first-born children of the normals, 21% were born out of wedlock , about a third lower than the figure for the United States as a whole, presumably reflecting the advantaged backgrounds from which the sibling sample was drawn. Their bright siblings were much lower still, with less than 10% of their babies born illegitimate. Meanwhile, 45% of the first-born of the dull siblings were born outside of marriage. The inequalities among siblings that I have described are from 1993 and are going to become much wider in the years ahead. The income trajectory for low-skill occupations usually peaks in a worker's twenties or thirties. The income trajectory for managers and professionals usually peaks in their fifties. The snapshot I have given you was taken for an age group of 28-36 when many of the brights are still near the bottom of a steep rise into wealth and almost all the dulls' incomes are stagnant or even falling. . . . The inequalities I have presented are the kind you are used to seeing in articles that compare inner-city children with suburban ones, black with white, children of single parents with those from intact families. Yet they refer to the children of a population more advantaged in jobs, income and marital stability than even the most starry-eyed social reformer can hope to achieve. You may be wondering whether the race, age or education of siblings affects my figures. More extended analyses exist, but the short answer is that the phenomena I have described survive such questions. Siblings who differ in IQ also differ widely in important social outcomes, no matter how anyone tries to explain away the results. Ambitious parents may be dismayed by this conclusion, but it is none the less true for all that. A final thought: I have outlined the inequalities that result from siblings with different IQs. Add in a few other personal qualities: industry, persistence, charm, and the differences among people will inevitably produce a society of high inequalities, no matter how level the playing field has been made. Indeed, the more level the playing field, and the less that accidents of birth enter into it, the more influence personal qualities will have. I make this point as an antidote to glib thinking on both sides of the Atlantic and from both sides of the political spectrum. Inequality is too often seen as something that results from defects in society that can be fixed by a more robust economy, more active social programmes, or better schools. It is just not so. The effects of inequality cannot be significantly reduced, let alone quelled, unless the government embarks on a compulsory redistribution of wealth that raises taxes astronomically and strictly controls personal enterprise. Some will call this social justice. Others will call it tyranny. I side with the latter, but whichever position one takes, it is time to stop pretending that, without such massive compulsion, human beings in a fair and prosperous society will ever be much more equal than they are now. |
#32
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IQ and what it means in adulthood
On Nov 12, 10:06 am, toto wrote:
On Sun, 11 Nov 2007 20:09:36 -0800, Beliavsky wrote: The book "The Bell Curve" (1994) by Herrnstein and Murray The book and it's statistical analyses are flawed. Hernstein and Murray start with a theory, then *lie* with statistics to support their theory. http://epaa.asu.edu/epaa/v4n20.html "Lie" is a strong word, and unless you can show that Herrnstein and Murray did not believe what they were writing, you should not have used it. Looking at Table 1 at the link you provided, using the critic's revised measure of socioeconomic status (SES) still leaves IQ with a larger t-stat than SES in predicting whether an adult will live in poverty. |
#33
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IQ and what it means in adulthood
On Nov 11, 2:35?am, Chookie wrote:
In article , "Donna Metler" wrote: My totally uninformed guess is that you'll probably find more "successes" in the second band of IQ-the high achievers for whom things were easy in school, but who weren't "out there" to the point of being misfits. Leta Hollingworth defined the IQ band 125-155 as "socially optimal intelligence" back in 1926! However, the IQ scores she was talking about aren't directly comparable to today's scores, and there is no simple way to convert them to today's scores (as in those days ratio scores changed with one's age). If I were going to figure out what figures Leta Hollingworth would use today, I'd have to see what age most of the children she was working with were tested at, and find out what the standard deviation was for the scores for that age. Just to take a wild guess, I'd say socially optimum intelligence these days would be roughly one to two-and-a-half standard deviations from the mean, or 115 to 137. But I suspect that "socially optimal intelligence" varies a great deal by circumstance -- a severely unintellectual environment being hard on persons of almost any level who actually care about learning. I agree with Ericka about the difference in average IQ levels between breastfed/formula-fed populations not being the real concern. To me, it's a question of whether something, who knows what, is happening that affects brain development adversely in formula-fed children. The other thing that always bothers me is that you can't tell from an *average* difference how large the *maximum* effect might be. I mean, obviously in this case it's not possible that 9 out of 10 are unaffected and the 10th takes a hit of 70 points, but there's nothing in the *numbers* that eliminates that possibility. Incidentally, 7 points sounds high -- I thought once confounding factors were out of the question, and when you weren't talking about premature babies, it got down to more like 3 points? But there are of course a bunch of different studies around. --Helen |
#35
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IQ and what it means in adulthood
In article . com,
Beliavsky wrote: Each pair consists of one sibling with an IQ in the normal range of 90-110 ,a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the bright) or lower than 90, putting him in the bottom quartile (the dull). These constraints produced a sample of 710 pairs. Actually, I have a problem with these definitions. For most of the research I've seen, gifted means either the top 10% for IQ or (more frequently) IQ130, which is the top 5%. THe definition of 'bright' is rather too broad here, and I wonder how the stats would look if the authors had used a better-accepted definition. Secondly, giftedness is strongly heritable, with a gifted child's siblings, parents and grandparents usually of a similar intelligence (within 5-10 points -- see http://www.hoagiesgifted.org/we_have_learned.htm). I don't know if *IQ* is as strongly heritable in the entire population, but if it is, there is a good chance of these 710 pairs being aberrant. My 2c. Lastly, of course, we haven't seen any definition of 'success' yet. Here's my 'success' story: A good friend of mine discovered that one of his workmates had known me at high school. She naturally enquired as to what I was doing these days, and when he said I was a librarian, looked rather surprised. "I thought she was smarter than that!" So there you are -- librarianship is intrinsically Unsuccessful! -- Chookie -- Sydney, Australia (Replace "foulspambegone" with "optushome" to reply) http://chookiesbackyard.blogspot.com/ |
#36
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IQ and what it means in adulthood
"Chookie" wrote in message news:ehrebeniuk-C905B0.22233513112007@news... In article . com, Beliavsky wrote: Each pair consists of one sibling with an IQ in the normal range of 90-110 ,a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the bright) or lower than 90, putting him in the bottom quartile (the dull). These constraints produced a sample of 710 pairs. Actually, I have a problem with these definitions. For most of the research I've seen, gifted means either the top 10% for IQ or (more frequently) IQ130, which is the top 5%. THe definition of 'bright' is rather too broad here, and I wonder how the stats would look if the authors had used a better-accepted definition. Secondly, giftedness is strongly heritable, with a gifted child's siblings, parents and grandparents usually of a similar intelligence (within 5-10 points -- see http://www.hoagiesgifted.org/we_have_learned.htm). I don't know if *IQ* is as strongly heritable in the entire population, but if it is, there is a good chance of these 710 pairs being aberrant. That might be a difficult one to show as I suspect that generally if one child is breastfed there's a good chance that siblings are breastfed to a greater or lesser extent. You've also got the argument of nurture as well, as if a parent did well at school, they probably have more resources to call on to help their children/want to help their children. I think there was some research done to show that ability maths is a recessive gene, which means that my children don't have any chance of not being mathematical without mutation, but my dad's mathematical ability came out of nowhere. My 2c. Lastly, of course, we haven't seen any definition of 'success' yet. Here's my 'success' story: A good friend of mine discovered that one of his workmates had known me at high school. She naturally enquired as to what I was doing these days, and when he said I was a librarian, looked rather surprised. "I thought she was smarter than that!" So there you are -- librarianship is intrinsically Unsuccessful! So you're the library Dragon are you? :-) Debbie |
#37
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IQ and what it means in adulthood
"Welches" wrote in
: That might be a difficult one to show as I suspect that generally if one child is breastfed there's a good chance that siblings are breastfed to a greater or lesser extent. that's not a good assumption to make. my older brother was breastfed until 5 months or so, when he bit mom. neither i nor my younger brother ever got a chance to breastfeed after that... You've also got the argument of nurture as well, as if a parent did well at school, they probably have more resources to call on to help their children/want to help their children. I think there was some research done to show that ability maths is a recessive gene, which means that my children don't have any chance of not being mathematical without mutation, but my dad's mathematical ability came out of nowhere. now that's interesting. i had some difficulties with math, but mostly with how it was being taught, not the actual math (once explained *properly*, the light dawned & i was good at it). my father's father, father & brothers are very good at math. my SO is good at math. did i just miss the recessive math gene? am i a 'carrier', so my son will get the gene (since his dad has the math gene)? hmmm. Lastly, of course, we haven't seen any definition of 'success' yet. heh. i have an IQ of 137. i'm a farmer. i dated a guy at MIT who was pretty close to my IQ. he had a dual major in math & philosophy. my dad asked him at dinner once what he planned to do with that dual major. BFs reply was a thoughtful "Well, there's really only two things i *could* do with a dual in math & philosophy. I can either teach, or become a farmer..." i wonder which he did... lee |
#38
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IQ and what it means in adulthood
Beliavsky wrote:
http://www.eugenics.net/papers/murray.html IQ Will Put You In Your Place By Charles Murray From the Sunday Times, UK, May 25 1997. An arcane debate about statistical methods ensued. Ummm, that was not an "arcane" debate. That was Methodology 101. Then several American academics began using a powerful, simple way of testing who was right: instead of comparing individual children from different households, they compared sibling pairs with different IQs. How would brothers and sisters who were nurtured by the same parents, grew up in the same household and lived in the same neighbourhood, but had markedly different IQs, get on in life? This throws up red flags right away. Siblings tend to have similar IQs. When there are marked IQ differences among siblings, right away it raises the issue of whether there was something else going on along with the IQ differences. A very large database in the United States contains information about several thousand sibling pairs who have been followed since 1979. To make the analysis as unambiguous as possible, I have limited my sample to brothers and sisters whose parents are in the top 75 per cent of American earners, with a family income in 1978 averaging £40,000 (in today's money). ? First of all, this commits a major methodological flaw of assuming your conclusion in drawing your sample. Bad, bad researcher! Families living in poverty, or even close to it, have been excluded. The parents in my sample also stayed together for at least the first seven years of the younger sibling's life. Again, skewing the sample based on assuming the anticipated results hold true. You're supposed to *test* these things, not build them into your research design.. Each pair consists of one sibling with an IQ in the normal range of 90-110 ,a range that includes 50% of the population. I will call this group the normals. The second sibling in each pair had an IQ either higher than 110, putting him in the top quartile of intelligence (the bright) or lower than 90, putting him in the bottom quartile (the dull). These constraints produced a sample of 710 pairs. It would be very interesting to see the profile of the groups, at this point. I suspect we'd see some interesting anomalies. How much difference did IQ make? Earned income is a good place to begin. In 1993, when we took our most recent look at them, members of the sample were aged 28-36. That year, the bright siblings earned almost double the average of the dull: £22,400 compared to £11,800. The normals were in the middle, averaging £16,800. And did they take birth order into effect? Quite a few studies now seem to show sizeable birth order effects on earnings, type of occupation, and risk tolerance (along with small IQ differences). Clearly a confound, and one that might explain a decent chunk of the results independently of IQ. Put together birth order issues and the odds that a child with normal or above IQ parents and siblings would have low IQ without any other disability that might also affect earnings or success, and you've got some holes you could drive a truck through. Best wishes, Ericka |
#39
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IQ and what it means in adulthood
On Nov 13, 7:57 am, enigma wrote:
heh. i have an IQ of 137. i'm a farmer. i dated a guy at MIT who was pretty close to my IQ. he had a dual major in math & philosophy. my dad asked him at dinner once what he planned to do with that dual major. BFs reply was a thoughtful "Well, there's really only two things i *could* do with a dual in math & philosophy. I can either teach, or become a farmer..." Today there are more options. Many math majors from MIT have the aptitudes to make a lot of money on Wall Street as quants or (even better) traders. I got a PhD in physics and took the former route. Math skills are more valued on Wall Street than they were say 30 years ago. Some mathematicians have done very well managing money themselves, for example James Simons: http://www.forbes.com/lists/2006/10/5GZ7.html Age: 68 Fortune: self made Source: Hedge funds Net Worth: 2.6 Country Of Citizenship: United States Residence: East Setauket, New York, United States, North America Industry: Investments Marital Status: married, 3 children Massachusetts Institute of Technology, Bachelor of Arts / Science University of California Berkeley, Doctorate Degree from MIT; taught at Harvard. Worked as code breaker for Department of Defense during Vietnam. Founded Renaissance Technologies hedge fund firm 1982. Flagship Medallion fund averaging 34% annual returns since 1988. Most expensive fees in the business: 44% of profits, 5% of assets. Hires Ph.D.s instead of M.B.A.s; employees use computer modeling to find market inefficiencies. Launching fund for institutional investors that could handle $100 billion. Chairs Math for America; group donated $25 million last year to train 180 New York City math teachers. Consulting companies are also looking for generally smart people. A significant fraction of people from elite universities that I know of are teaching at test preparation companies such as Kaplan. I think such companies require high test scores from applicants. |
#40
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IQ and what it means in adulthood
On Nov 10, 7:02 pm, Sarah Vaughan wrote:
Anyway, it would probably help if I gave the context here - the debate was about the studies showing a correlation between breastfeeding and increased IQ, and - if that association is real and not due to a confounder - what it means in practice. I must say I was never terribly impressed by the kind of numbers I was hearing - in the studies being discussed, the average difference was seven IQ points, which just didn't really sound like that much in practice to me. But the question came up, and it got me wondering whether I was right about that or not. A recent article in the Washington Post http://www.washingtonpost.com/wp-dyn...1001271_3.html said "A recent study by Scottish researchers asked whether the higher IQs seen in breast-fed children are the result of the breast milk they got or some other factor. By comparing the IQs of sibling pairs in which one was breast-fed and the other not, it found that breast milk is irrelevant to IQ and that the mother's IQ explains both the decision to breast-feed and her children's IQ." I don't what study is being referred to. A finding that breast milk is irrelevant to IQ certainly contradicts conventional wisdom. |
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