Parental Income and Educational Attainment
The NYT’s Economix blog offers a chart showing the strong correlation between parental income and SAT scores:
It is, of course, possible that this effect is entirely caused by differences in parental IQ. That said, there’s no evidence that it’s entirely caused by differences in parental IQ. But such is Greg Mankiw’s zeal to defense social and economic inequality and injustice in the United States that he slams the NYT for failing to advance this evidence-free genetic determinist theory.
But for another look at the non-genetic heritability of socioeconomic status, consider this chart Peter Orszag brought to my attention some time ago:
You see that whether or not one goes to college turns out to be closely related to parental income even when you account for differential levels of student achievement. In particular, children of average intellectual ability are likely to go to college if their parents are in the top income quartile, but not otherwise. Personally, I have no doubt that some social stratification in the United States is due to genetics, but we would have to be living in a very different country before I started using that hypothesis to wave away every potential concern about inequality.
86 Responses to “Parental Income and Educational Attainment”
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August 29th, 2009 at 8:37 am
I agree with MY, but I have to say that my gut reaction to both of these charts is still, “whoa! there’s a much stronger correlation here than I would have expected.”
The upper chart doesn’t impress me that much, because I’m not sure if it accounts for the difference between one-parent and two-parent households.
But the lower chart — the one MY likes more — actually seems to me more striking. I’m particularly surprised by the low college enrollment rates of well-off kids with low math scores. I would have assumed those kids would all be going to college anyway. And I’m almost as struck by the way income differences flatten out for kids in the top third.
All that said, here’s what strikes me as the bottom line, politically: It’s not clear to me that — even if you gave a great deal of weight to genetic determinism — it would make much difference for “concerns about inequality.” I want everyone to have healthcare, and I really don’t care whether they’re not seeing a doctor because they didn’t have opportunity or because they’re not a math whiz. “They’re not math whizzes, so let them go without healthcare” seems to me a non-starter, morally.
August 29th, 2009 at 8:43 am
If you yourself have a college education, you should know about heritability and how group differences (even in clearly heritable traits such as height) cannot be considered as due to genetic differences. Recall: Height is heritable, heights of Japanese and US men in 1950 differed by about 8 inches. Those differences have been declining at steady rate. Mixing of gene pools? Height is not heritable? Nope, genes in different environments. This is the freshman lecture version. But on this you are spouting off like folks who have dinosaurs and men living together– and you will only confuse people. Know the science, know the math, or at least do a cursory reading of Bio or Psych 1 text books from the current century. (one last snark: if SAT is so unchangeable an indication of intelligence, why learn algerbra at all? ooops, one more snark: if SAT is such a great indicator of genetic differences in intelligence why are people paying Kaplan so much?
August 29th, 2009 at 8:45 am
I have no doubt that some social stratification in the United States is due to genetics…
Really? I’d like to see some evidence of that. The fact that George W Bush was elected and then re-elected seems to indicate the opposite of what you’re implying here. Yes, it’s still “due to genetics”, but in a completely different sense.
August 29th, 2009 at 8:55 am
I’m not going to get into the debate about genetic determinism, because I think the ratio of evidence to strength-of-conviction is pretty low on both sides of that argument.
What’s more interesting to me is this: Assume all income differences in the US could be explained by heritable traits (genetic or not, it actually doesn’t matter). What would be the political implication?
Well, oddly, it would blow a huge hole in right-wing economic thinking. The logic of the right is that we can’t construct an egalitarian society because it would reduce people’s incentives to work harder. My inability to afford routine preventive care is just the goad I need in order to innovate and excel.
On the other hand, if I’m doing about as well as I can (given the piece of cheese I call a brain), there’s not a lot of point in withholding the basic elements of human welfare from me. By denying me healthcare, you’re not goading me to excel, you’re just guaranteeing that my (unavoidable) inequality will produce (avoidable) misery and threats to public health.
August 29th, 2009 at 8:55 am
Orszag’s bar chart is for math test scores. There are other kinds of performance, I believe.
August 29th, 2009 at 8:58 am
A third covers rather a lot of variation…
August 29th, 2009 at 9:05 am
My guess is that the income chart is really showing whether the parents attended college. Attending college => higher income => children attending college.
August 29th, 2009 at 9:18 am
I wonder if this will eventually look different in Kalamazoo, MI. A group of anonymous donors there have recently created the Kalamazoo Promise, providing college scholarships to all graduates of the public school system there. The scholarships range from 100% of tuition down to 50% (IIRC) depending on how many years the child has attended KPS schools.
The promise has not only removed financial barriers to college but as created a different, more ambitious, mindset among many students. There is now a widespread belief that everyone should strive to go to college, even to a community collge to at least learn a trade skill.
What a wonderful gift.
August 29th, 2009 at 9:18 am
I’ve seen Matt bring up this trend toward increasing inequality a number of times, but I’ve never seen mention of one possible cause that seems to me to be obvious. A number of sectors of the economy, and therefore a large number of income earners depend upon government services. Copyright protection is one obvious service. Other such services include trade deals with other countries, security services, guaranteeing to a broadcaster that no one else will interfere with his signal, among others. Over the past several decades, these services have become more valuable, but our tax policy has been to make them cheaper. The upshot is that the wealthiest sector of the population has been having its income regularly augmented by the government, via these services, while the cost charged for the services has been going down. Most other folks have not had that benefit. Would this not explain much of the growth in income inequality?
August 29th, 2009 at 9:36 am
Well, my son made around 790 on his Math SAT, so I should be a multi-millionaire. Extrapolating from the above curve.
Yeah, right.
From what I’ve seen, it takes real hard work to score at the high levels on SATs. Kids from wealthy families often lack the motivation to work that hard. Through no fault of their own –they know daddy is rich so they know there’s a big safety net under them. Removes the desperation.
Expensive prep schools raise their median SAT scores by recruiting the cream of the crop from the
middle and working classes –with scholarships.
Having some tough plebes from the lower classes helps to motivate the rich kids to work harder in class — and if the rich kids don’t measure up, that’s what teacher recommendations, grading on a curve , and SAT boot camp are supposed to remedy.
Plus the rich kids can offer expensive baubles to lure the smart kids into helping them with homework, providing informal last minute tutoring,etc
So great wealth can help — but it often prevents failures like George W Bush from being weeded out. That’s the problem with aristocracies — they don’t spay the culls.
August 29th, 2009 at 9:37 am
On the other hand, if I’m doing about as well as I can (given the piece of cheese I call a brain), there’s not a lot of point in withholding the basic elements of human welfare from me. By denying me healthcare, you’re not goading me to excel, you’re just guaranteeing that my (unavoidable) inequality will produce (avoidable) misery and threats to public health.
Good comments.
August 29th, 2009 at 9:40 am
Re: In particular, children of average intellectual ability are likely to go to college if their parents are in the top income quartile, but not otherwise
Is this supposed to be surprising? It’s perfectly intuitive, unless you actually believe that America is a meritocracy instead of a bloated oligarchic mess.
August 29th, 2009 at 9:42 am
It’s kind of Matt to host comments for Mankiw’s blog, just like he does for the cowards at The Corner.
August 29th, 2009 at 9:44 am
I mean, how could someone like George W Bush get through Andover, Yale and Harvard Business School without a pretty heavy
thumb being on the scale? actually, without the fat ass butcher sitting on the scale?
August 29th, 2009 at 9:48 am
Re: Well, oddly, it would blow a huge hole in right-wing economic thinking. The logic of the right is that we can’t construct an egalitarian society because it would reduce people’s incentives to work harder. My inability to afford routine preventive care is just the goad I need in order to innovate and excel.
Good point. I’m agnostic about genetic differences in intelligence (I’m sure they exist, but I don’t know how important that factor is). But the larger they are, the more important it is for the state to redistribute wealth in order to suppress the emergence of a hereditary aristocracy.
August 29th, 2009 at 9:55 am
My gut tells me that the point being made by the bottom chart is probably still correct, but a division into thirds is not remotely close to enough detail to prove that income matters even after controlling for test scores. Kids from wealthy families get higher scores that those from poor families. That means that within that middle third, probably more of the people towards the top of the range are wealthy, and more of those at the bottom of the range are poor. Charts are misleading – I’d be much happier to see the results of the actual statistical test.
August 29th, 2009 at 10:00 am
I seem to have been reduced to posting links to other blogs. Anyway, here’s Krugman’s take on Mankiw:
Oh, Kay. Greg Mankiw looks at a graph showing that children of high-income families do better on tests, and suggests that it’s largely about inherited talent: smart people make lots of money, and also have smart kids.
But, you know, there’s lots of evidence that there’s more to it than that. For example: students with low test scores from high-income families are slightly more likely to finish college than students with high test scores from low-income families.
It’s comforting to think that we live in a meritocracy. But we don’t.
http://krugman.blogs.nytimes.com/2009/08/28/heredity-environment-justice/
August 29th, 2009 at 10:11 am
Didn’t yo read outliers? Gladwell explains this discrepency for what it is-a lack of learning outside of school by lower class students
August 29th, 2009 at 10:16 am
I recommend reading Steven Pinker “the blank slate.” Certainly some people are born smarter than others. They will be more likely to succeed and earn material wealth. That said, a person born of average intelligence will benefit from growing up in a wealthy family when compared to someone of equal intelligence who grows up in a family lacking material wealth. A wealthy family will ensure their child goes to a good school, they will more likely me highly educated themselves and able to provide guidance along the way and value education. In addition, wealthy families can pay for additional training and tutoring for standardized test practice. All of these lead to higher test scores on average.
August 29th, 2009 at 10:17 am
Regardless of the causes, intelligence is regularly shown to be normally distributed across the US population. This means that roughly 30% of the population is unable to do high school level work and 70% is unable to do college level work. These findings haven’t varied over many years.
The import is that this country cannot expect to educate everyone to be rocket scientists, but rather should be considering how to provide an environment that allows the various segments a chance at a decent life.
Countries such as Germany do a much better job of this and one reason is that they don’t pretend that everyone has equal abilities, with lack of effort making the difference. Instead, they provide relevant schooling, job training and job placement programs to accomodate the variation.
August 29th, 2009 at 10:35 am
@20: I think that’s interesting. There’s something weird about the way this has all played out in the US.
The right’s passion for a voluntarist model of economic life, and the left’s passion for theoretical egalitarianism — an egalitarianism of unlimited “opportunity” — dovetail to produce some perverse consequences.
August 29th, 2009 at 10:49 am
It should be pointed out that, according to the second chart, it’s MUCH better to be smart but poor than rich but stupid. The enrollment rate is 68% for those in the top third of math scores but lowest income quintile, versus 27% for those in lowest third of math scores but highest income quintile.
Obviously having affluent parents is a huge plus, as both charts show. But again, if you had your choice, the smart money’s on smart-but-poor rather than rich-but-stupid.
Or at least upper-middle class but stupid, since the top income quintile starts at about $90,000.
August 29th, 2009 at 10:59 am
Another interesting idea that is litle-discussed is; what if society were perfectly meritocratic? If rewards went exclusively to the deserving , would that be a desirable outcome?
I would argue that perfect meritocracy would still leave the same issues of equitable distribution. Just because I’m a genius doesn’t equate to “I deserve much and you deserve little”. I would prefer a minimum standard of living and a ceiling on wealth – and most certainly a very high tax on estates.
August 29th, 2009 at 11:04 am
I’d like to point out that (a) Mankiw slams the NYT for poor understanding of statistical influences, and then makes a small comment to end about heritability of IQ and (b) I’d really like to see some error bars on that graph! Is this significant? How big is the variance between groups?
August 29th, 2009 at 11:09 am
Mankiw is an economic Calvinist.
But one point that doesn’t seem to have been brought up in the comments is the obvious correlation between parental income and early childhood nutrition. We know – for a fact – that early childhood nutrition is crucial for development. And if you get poor or hideously poor nutrition in these crucial years, then you show a huge disparity in such things as IQ. A disparity that literally dwarfs such things as genetic influences in such matters.
But hey, Mankiw looks at that data and can’t think of anything besides a leaky toilet associated with being poor.
He really is a heartless, evil bastard.
Glad you like him, Matt.
August 29th, 2009 at 11:18 am
Nature (genetics) determines how big the glass is. Nuture (environment) determines how full the glass becomes.
August 29th, 2009 at 11:28 am
I’m stunned that the first attack on this ridiculous argument of Mankiw’s isn’t CLASS CLASS CLASS. Only, and only, if you did divided twin pair studies from different classes might you have a genetic argument.
But all this shows is what sociologists of education have known for forever – people from high SES backgrounds (i.e, the middle class and above) put an enormous value on educating their children and devote lots of family resources towards their education; moreover, even if (as the second chart shows) their child is not academically strong, they can still use their financial means to purchase a place in college.
Luckily, there’s a quite easy way to change that second chart to be more egalitarian – make college free.
August 29th, 2009 at 11:31 am
Asurai – that’s not what the chart shows me – especially if you look at the updated version of that chart using 2002 data. It’s better to be rich than smart in all but the lowest categories, and even then it’s an even break.
And the sheer gap in rates between the highest-achieving poor and the below average rich is quite stunning.
August 29th, 2009 at 11:50 am
Hey, Steven, thanks for that link. There’s actually a big difference between the chart MY includes and the chart Steven is linking to. Steven’s chart would have been much more favorable for MY’s thesis, I think.
August 29th, 2009 at 12:13 pm
No problem. Shouldn’t be a surprise really; combine increasing economic inequality between 1998 and 2002 with the health-insurance-like rising costs of a college education, and the effect is going to get a lot worse.
August 29th, 2009 at 12:14 pm
There’s a shitload of difference between acknowledging that people have different abilities, and doing what Matt just did.
“Personally, I have no doubt that some social stratification in the United States is due to genetics…”
No matter what he goes on to say from there, he’s just essentially declared that the upper class is the upper class because they are genetically superior to everyone else. goes a long way toward explaining why he thinks the rest of us should just stfu and listen to our wise masters in Washington, doesn’t it?
Really though, you people don’t even kind of know what you’re talking about. What evolutionary mechanism allowed for this to occur? You realize that when it comes to positive traits like intelligence, you can’t just breed them in by putting two smart people together. You have to outright breed all other traits OUT of the population. Given that there is simply no mechanism to make the moronic upper class individuals lose their status, there is no way to force them out of the upper class gene pool. This would prevent this from occurring.
You all sound as retarded as “Black people is better at sports cuz uv slavery!!!”. Evolution does not work like that, and it doesn’t work that quickly.
But hey, Matt has found a racist argument that justifies his classism! Lets run with it!
Do you morons even know what an allele is? A bunch of economists talking about evolution. That always fucking ends well.
August 29th, 2009 at 12:25 pm
Especially given the degree of incest among much of the world’s elite up until fairly shortly. And absolutely no evolutionary change of any great degree can be promulgates across a worldwide species that waits 13-22 years between generations in the span of a few decades, or even centuries. It’s not possible.
The mind bogglingly stupidity of Matt’s assertion that “genetics” as the term is generally understood, has ANYTHING to do with class is just amazing.
This argument is roughly the intellectual equivalent of “Why don’t we print money to get us out of debt!” Sure, it sounds good when you know absolutely nothing, but you may as well have opened a can of paste and started to chow down to the rest of us.
August 29th, 2009 at 12:40 pm
This was thoroughly delt with on Brad DeLong’s blog, in particular with the paper sent to him. I would simply note that it is an ironic posting from an economist who served a president with high income but low reading comprehension.
August 29th, 2009 at 1:49 pm
Please explain this:
“Personally, I have no doubt that some social stratification in the United States is due to genetics…”
This can be taken to mean any number of things. Please elaborate.
August 29th, 2009 at 2:12 pm
I’m particularly surprised by the low college enrollment rates of well-off kids with low math scores. I would have assumed those kids would all be going to college anyway. And I’m almost as struck by the way income differences flatten out for kids in the top third.
To be in the lower third in math scores means essentially that you were below the 34th percentile; that is to say, your SAT math score was something like on the order of 500 and below. Which is pretty striking.
I genuinely don’t know how society could ideally deal with kids from wealthy backgrounds with such a low intelligence placement, despite (what is likely) a reasonable deal of education and preparation. On one hand, to actually economically sort them in a way comparable to their ability would almost be a incentive for their parents, if not in business, to engage in corrupt practices to save up money for the kid, who presumably cannot earn a comparable income independently.
August 29th, 2009 at 2:16 pm
That’s why a genuine meritocracy is somewhat undesirable; because in a genuinely meritocratic society we have no way of accounting for the familial identity of human relationships.
That is to say, a meritocratic society would have the unsolvable paradox of (income and achievement-wise) rich parents and poor kids,, that would, I theorize, lead to a much greater incentive for the accumulation of personal and family wealth and the undiluted passing down of that wealth, to prevent precisely that paradox from materializing.
(If I were to be rich and my kids dumb, I would almost certainly pull every string available to give the kids preferential (and probably unfair) advantages, in addition to accumulating wealth for their benefit. I expect a great proportion of other human beings to behave in the same manner.)
August 29th, 2009 at 2:21 pm
And also, the rule of thumb for intergenerational (one, single generation; not multiple generations) hereditability of intelligence is a factor of 0.5. That is the scientific consensus. This isn’t Charles Murray; this is mainline, liberal scientists.
Those who are disputing the intergenerational hereditability of intelligence, by something close to that factor, (not long-term, multi-generational) are uninformed fools.
August 29th, 2009 at 2:23 pm
Really though, you people don’t even kind of know what you’re talking about. What evolutionary mechanism allowed for this to occur? You realize that when it comes to positive traits like intelligence, you can’t just breed them in by putting two smart people together.
You know, people are talking about averages. Is the upper class, on average, smarter and more intelligent and the poor? I think that is a resounding yes.
By the way, a population of (let’s just say) 95% smart people and 5% dumb people is still going to produce, on average, smarter than average people.
Again, part of the genetic predisposition is purely intergenerational. Long term (give or take 20 generations), I doubt very much genetics play as much of a factor.
August 29th, 2009 at 2:33 pm
And by the way, this is pretty inaccurate:
I wonder if there was a study done comparing the children of wealth men and trophy wives, with the children of wealthy men and spouses of similar socio-economic background (Miss Porter’s, Bryn Mawr), if there would be noticeable differences in intelligence between two groups. Anyone taking bets that the second group would be considerably smarter?
August 29th, 2009 at 3:08 pm
Myles:
1. You’re making a huge mistake equating SAT scores or college attainment with intelligence. At best, they correlate with education, which is not the same thing. You can have people who have modest intellectual aptitude, but who use education and effort and experience to outpace someone who’s gifted but doesn’t pursue their abilities, and so on and so forth.
2. The dispute isn’t whether parents who do well in school produce children who do well in school – it’s how the relationship works. Now Murray and his lot would say it’s genetics, but I would say its much more likely to be parents teaching their children. Unless someone’s been doing a LOT of separated twins studies that I don’t know about, there’s no evidence that genetics are playing a factor.
3. It’s possible that in a pure meritocracy that parents might try to further avoid its effects – the question is whether they would be able to. If education is free from birth to PhD, if cultural enrichment is widespread, if hiring and promotion are done on merit not networking, and if you have a redistributive welfare state and a near 100% inheritance tax on great fortunes, you can shut down most of the methods of giving people an unfair advantage.
August 29th, 2009 at 3:27 pm
2. The dispute isn’t whether parents who do well in school produce children who do well in school – it’s how the relationship works. Now Murray and his lot would say it’s genetics, but I would say its much more likely to be parents teaching their children. Unless someone’s been doing a LOT of separated twins studies that I don’t know about, there’s no evidence that genetics are playing a factor.
I told you already, the hereditability of intelligence is scientifically recognized to be around 0.5, or half-and-half.
Are you intentionally being blind? Of course intelligence is, to some extent, and with a number of qualifications, inheritable. Of course intelligence, just like other biological traits, is inheritable, because otherwise Darwinian evolution, from monkey to men, would be impossible.
It’s possible that in a pure meritocracy that parents might try to further avoid its effects – the question is whether they would be able to. If education is free from birth to PhD, if cultural enrichment is widespread, if hiring and promotion are done on merit not networking, and if you have a redistributive welfare state and a near 100% inheritance tax on great fortunes, you can shut down most of the methods of giving people an unfair advantage.
Well, no. Hiring and promotion are done by humans. Humans will have familial tendencies, and where the external restrictions on such hereditary tendencies are the strongest, nepotism will be at its most persistent. Cf. Soviet Union, the Late History of.
To brutally repress such basic human tendencies would, essentially, be equivalent to having a totalitarian state, and the harm would outweigh the benefits (per the Soviet Union) by a factor of millions.
August 29th, 2009 at 3:29 pm
In fact, such a situation would mean the complete eradication of human freedom, or the abolition of negative liberties in entirety.
Such a scenario is neither desirable nor likely.
August 29th, 2009 at 4:18 pm
Matt,
So where does Mankiw say that IQ entirely explains the effect as you state?
August 29th, 2009 at 5:32 pm
“I told you already, the hereditability of intelligence is scientifically recognized to be around 0.5, or half-and-half.”
Anything considering iq has shitloads of political financing and selective study pushing behind it. Dont trust any study considering iq heredity you did not fake yourself!
August 29th, 2009 at 5:34 pm
Nearly all of the posters seem to be making the argument that going to college and being middle class or higher, is the only valid choice. Indeed, if anyone doesn’t reach this level is must be the result of some conspiracy on the part of the upper class to keep them down.
The idea that some people would prefer to graduate from high school and go directly into some blue collar occupation must be the result of some sort of false consciousness. Does everyone really think that if everyone had every opportunity they would all choose to go to Princeton and become a partner at McKinsey and live in Greenwich? Is it possible someone might prefer to not go to college, get a job with the gas company and live on Staten Island?
Long story short, are the working class and upper class that way because of some conspiracy or are those different social classes the result of perfectly valid choices resulting from different values.
August 29th, 2009 at 7:57 pm
Motivation is a factor, too, not just intelligence. Someone who knows that their college education will be funded has more motivation to do well on an SAT. I took my first one after a night of tripping, didn’t study, but did well enough to get into the schools I wanted to attend. Having partied through high school without caring about grades, I found the money wasn’t there. So I enlisted. Retook the SAT when I got out, because the requisite score had been raised. Studied a little bit and got the extra 40 points I needed. Got in to U.T. Still paid for most of my education because VEAP was a raw deal, but tuition was low at U.T. I lived well on a low budget, and worked. I wanted the education, badly.
I was raised with the expectation that I would go to college. It wasn’t until I reported to my mother how well I was doing in school that I realized I was supposed to marry up. I learned to value education, for the sake of education, anyway.
College isn’t for everybody, and judging from the lack of interest in education I’ve seen in a lot of people attending college, it appears to be a middle-class right of passage for many students, and education isn’t the goal—money is.
August 29th, 2009 at 8:23 pm
I took my first one after a night of tripping, didn’t study, but did well enough to get into the schools I wanted to attend. Having partied through high school without caring about grades, I found the money wasn’t there.
Do you consider your decision, or anyones decison, to not study and spend the night “tripping” to have been a mistake?
Or is it rational for someone say, I’d rather have fun now and end up working at UPS or for the Gas Company, than study and end up some cube dwelling accountant or software engineer some day?
August 29th, 2009 at 9:05 pm
[...] purely causal because there may be an omitted variable bias, IQ for example. Paul Krugman and Matt Yglesias both attack Mankiw and point to graphs showing that income matters for college completion and [...]
August 29th, 2009 at 9:52 pm
A few simple facts might be helpful
1) SAT scores (especially SAT-Math scores) are essentially the same as scores on IQ tests, this was shown in a study by Frey and Detterman of Case Western Univ.
https://www.psychologicalscience.org/pdf/ps/Frey.pdf
2) IQ-type intelligence (or “g”) is a very strongly heritable trait, it is inherited to about the same degree as height. In older teens and adults the heritability of IQ-type intelligence is about 60 to 80%, the other 20 to 40% is due to nonshared environmental factors (i.e. factors that are not associated with the home and parenting effects).
3) There is a high degree of assortative mating in regard to IQ-type intelligence. In modern societies in which women are encouraged to pursue higher education and careers it is very common for smart women to marry smart men. Simple genetics would then predict that their children will tend to be of higher IQ.
4) Upper middle class parents (doctors, lawyers, business executives, entrepreneurs, professors, etc) who often have advanced degrees will of course tend to have higher IQs than lower class parents who are often high school dropouts or who had to struggle to cope with the cognitive demands of high school or community college courses.
5) Therefore, Professor Mankiw’s supposition (i.e. that upper middle class parents would tend to have higher IQs and that they would tend to pass on this highly heritable mental trait to their children) is entirely plausible. To suggest otherwise is simply disingenuous.
Perhaps people might try to educate themeselves about IQ-type intelligence by reading some articles by modern experts on the science of human intelligence such as:
Ian Deary (University of Edinburgh)
Arthur Jensen (U Cal Berkeley, Emeritus)
David Rowe (Univ Arizona, deceased)
David Lubinski (Vanderbilt)
Robert Plomin (Kings College London)
John DeFries (Colorado Univ)
Linda Gottfredson (U Delaware)
Dorret Boomsma (Vrije Universiteit Amsterdam)
Matt McGue (Univ of Minnesota)
Wendy Johnson (Univ of Minnesota)
Nicholas Martin (Queensland Australia
August 29th, 2009 at 10:22 pm
Arrgh but ye are nothing but barralfull er fools. It is not “intelligence” that detirmins who comes out on top but the size er the bolloks. reading throught his thread tis apparant to me that the tiny-testicled are overrepresented in the blog-reading category. Arguin about yer charts an yr graphs and yer studies…..” By Jesus third nipple ye give me the willies.
Survival on the high seas–which is the only true test er a man–comes down to charisma, will power, and cussidness. In other words, cojones. If ye doubt me argument, then try this thought experiment. Picture yerself in a long boat 7 days adrift, manned by none but by yerself and ol’ one eye. There’s but one cup er water left, sloshinf pittifuly arounda the bottom er the water barrel. You yerself got’s a masters degree. Me, I gots a reliable source er high qulaity testosterone. Whose going to be enjoying those last few swallers er water on day 8, me friend?
If ye guessed ol one eye, then yer wrong. It were a trick question. You would be drinkin that water becasue a plumb shipmate put the needs er his mates above his own. ANd because I got the sand to endure without needin that last cupful. I also have a manly sense er compassion. I would craddle yer curly head as ye slip away, mistaking me fer yer dear old ma, an me lettin ye. And then of course, I would eat yer sun-dried corpse, and live whatever number er days were further granted me by the mother sea.
So what is the lesson here? It’s desire, me freind. Lust fer life. Those who revel in existance and struggle, they’re the ones that come out on top. Maybe not on top er some corporate org chart, but on top er the list er the mother sea’s favorites. They are the blessed. They are the inheritors er the earth.
August 29th, 2009 at 10:43 pm
Re: Linda Gottfredson (U Delaware)
While I am not qualified to opine on the quality of her research, I just thought I would point out that Ms. Gottfredson (along with Arthur Jensen) have received funding from the Pioneer Fund, which had ties to the Nazis and is considered a hate group by the Southern Poverty Law Center.
August 29th, 2009 at 10:56 pm
Galtonian-
Note now, that I’m leaving the realm er wisdom and philosophy and engaging you souless pussies in yer own cramped arena:
What yer not getting, yer very impressive list-makin abilities not withstanding, is that while IQ may be heritible, there is no particular eveidence that it is iq determining-genes that we are inheriting. Instead it is just as reasonalbe to believe that what the high IQ’d are inheritin is competant prenatal care, good nutrition, a low stress envirionment, verbal parents, shelves full er books, expectations fer success, successful role models, breakfasts every mornin, varied experiences, privilidgs position in society, competent teachers in functionin schools, lack er daily fear, kind companions, cultural competence, a good nights sleep, hope….
So before ye start tell me that ye know something deep and mysterious about the world, raise 4 kids in a series of one bedroom apartments, motel rooms and cars while workin–when you can find work–at fast food restaurants. Then we’ll give them some IQ tests and see how yer theories hold up.
August 29th, 2009 at 11:16 pm
Why would I consider it “a mistake”? I went to the school I wanted to go to. I could have retaken it while I was in high school— it wasn’t consequential. I started working when I was 15. I could have paid for the retest myself, easily.
Because I transferred from a high school with trimesters to one with semesters and had taken a lot of different courses, I had the option of graduating a year early, and took it. I used to regret that I screwed around in high school, but once I got to college, having already been in the world and in the habit of being “on my own”, I found that I was more serious in my schooling than many, and not overwhelmed by the requirements of independence. The fact that I was paying for most of it myself, also made it MINE.
After being raised by an extremely repressive mother who was in the habit of saying things like, “You had better make straight As, stupid”, I took advantage of some of the freedom I had with my father, and accepted the consequences. Often, I skipped school to go to a library. I read three or four books that weren’t assigned a week throughout my high school experience.
High school was, overall, boring as hell to me and full of hormonally imbalanced drama queens of every stripe. I hung out with older people. Wasn’t inordinately fond of teenagers, and didn’t understood why they thought they had discovered everything from music to sex. Teen-aged girls drove me up the wall with all their stupid sniping and giggling, incessant bitching about their looks and bodies, and campaigns to label other girls sluts and make them suffer for it.
Twenty minutes of the class time was wasted taking roll, and I could often do well on tests without studying, which made showing up and sitting all day, a waste of time to me. My ass ached horribly from sitting in those chairs all day, and it was painful for me to be inert and indoors for so many hours at a stretch. An office job would be murder for me.
My high school chemistry and literature teachers are the only ones I have truly fond memories of. I remember almost all of my college instructors.
BTW, since people typically study for the SAT, and don’t typically study for IQ tests, I find those results highly specious and offensive on their face.
August 29th, 2009 at 11:29 pm
BTW, since people typically study for the SAT, and don’t typically study for IQ tests, I find those results highly specious and offensive on their face.
I’ll try and find the research for you. But, long story short… while there are companies like Kaplan et. al. that claim to be able to boost your SAT scores, the evidence that studying for the SAT’s does any good is pretty weak.
August 29th, 2009 at 11:43 pm
Check out Alex Tabarrok’s post over on Marginal Revolution on correlation between family income and child’s family income, for adopted vs. non-adopted kids. Note that the study Tabarrok quotes favors Mankiw’s hypothesis.
August 30th, 2009 at 1:18 am
But, long story short… while there are companies like Kaplan et. al. that claim to be able to boost your SAT scores, the evidence that studying for the SAT’s does any good is pretty weak.
I can back that up personally. My summer-long SAT prep routine, complete with tutors and so forth, was not as effective as some would like to think. Granted, my original score was quite high, so it was difficult to improve upon it, but nonetheless the evidence for SAT being a prep-able test is specious at best.
August 30th, 2009 at 1:23 am
The only way I think it was possible to improve SAT performance was to fundamentally improve comprehension and critical thinking skills through rigorous education and reading and essay-writing. That was certainly my experience.
But of course, that is exactly what the SAT measures.
Back to basics.
August 30th, 2009 at 1:37 am
I raised my GRE verbal score 70-100 points (to perfect) by cramming the week before the exam.
August 30th, 2009 at 2:08 am
I reviewed some math before taking the test the second time, because I had been out of school for four years. I think the improvement was better than the score itself would demonstrate. I did the same or better on the verbal part, but I had also continued reading and writing on my own.
Would a person who re-took the SAT after ten years of raising a family and working at a demanding job with no reading, writing, or math score as high as they did in high school? I’m guessing not, and don’t think it’s because they got stupid.
I’m sure there are geniuses in preliterate societies, the SAT doesn’t prove much—it’s a relative measure for people in the same pool competing with each other. A lot of people don’t test well, also. I do, but I’ve known people smarter than I who had difficulty with written tests.
August 30th, 2009 at 2:31 am
Note that the brains of more intelligent people are different in terms of cortical thickness and myelination (affects processing speed – Einstein had a larger number of glial cells which produces this). This is significantly heredible:
“The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited.”
(see New Scientist 9 March 2009 ‘High Speed Brains in the Genes’ and MIT Technology Review, March 24, 2009)
Also, see:
“Data from more than 8000 parent-offspring pairs, 25,000 sibling pairs, 10,000 twin pairs and adoption studies provide evidence that genetic factors play a substantial role in the variation of general intelligence, with heritability estimates ranging from 40 to 80%” —Burdick et al, Cognitive variation in DTNBP1 influence general cognitive ability. Human Molecular Genetics, 2006, Vol 15, No. 10.
“Heritability estimtes for intelligence quotient (IQ) range from 0.50 to 0.80. This makes IQ a suitable target for attempts to identify the specific genes involved.” Chorney et al, Role of the cholinergic muscarinic 2 receptor (CHRM@) gene in cognition. Molecular Psychiatry (2003) 8. 10-13.
“A substantial body of literature from twin, family and adoption studies documents significant genetic effects on human intelligence. Heritability estimates range from 40 to 80% and meta-analyses suggest an overall heritability of around 50%” Dick et al,
(2006) “Association of CHRM2 with IQ: Converging Evidence for Genes Influencing Intelligence.” Behavioral Genetics.
“Multivariate genetic analyses indicate that general intelligence is highly heritable, and that the overlap in the cognitive processes is twice as great as the overall phenotypic overlap, with genetic correlations averaging around .80.”
Plomin et al (2004) “A functional polymorphism in the succinate-semialdehyde dehydrogenase genes is associated with cognitive ability,” Molecular Psychology 9, 582-586.
August 30th, 2009 at 2:46 am
A lot of people don’t test well, also.
I often thought that was something a stupid workaholic would say.
As an example, you might give a group of people a test prep kit and give them 4 hours to study. You might give a second group a similar kit and give them 7 days to study. There is going to be a group that picks it up the first time, a second group that needs to study and a third group that just can’t get it. I think a great many of the “I just don’t test well” crowd arise from those who aren’t very intelligent who can, with enough effort, fake it.
August 30th, 2009 at 5:57 am
Yglesias totally mischaracterizes Mankiw’s argument. Mankiw never claims that test scores are “entirely” explained by genetics. He claims that, if one were to control for genetics, the test score vs. income curve would be “a lot flatter” (note not “completely flat”) — an entirely true statement which I suspect even Yglesias would have to admit.
Furthermore, Mankiw does not ask the NYT to advance any particular theory, but for presenting this graph as evidence for something that it is not, because it does not control for other factors. This is statistical sin that the press comits again and again, and for which it well deserves to be excoriated.
August 30th, 2009 at 6:27 am
Based on GPA and test scores, students from the lowest economic quintile are “underrepresented” by almost 50% at highly selective institutions.
The NACAC reported this spring that coaching has a demonstrable, but minimal impact in improving SAT scores – about 30 points. They also reported that in a substantial minority of cases, colleges reported that a 30 point gain could have a significant impact on the applicant’s chances of admissions.
August 30th, 2009 at 8:39 am
[...] to be purely causal because there may be an omitted variable bias, IQ for example. Paul Krugman and Matt Yglesias both attack Mankiw and point to graphs showing that income matters for college completion and [...]
August 30th, 2009 at 9:48 am
[...] be purely causal because there may be an omitted variable bias, IQ for example. Paul Krugman and Matt Yglesiasboth attack Mankiw and point to graphs showing that income matters for college completion and [...]
August 30th, 2009 at 10:02 am
[...] n’ont pas tardé pour tomber sur Mankiw : John Sides du blog The Monkey Cage, Brad DeLong, Matt Yglesias ou Paul Krugman. Seul Alex Tabarrok défend Mankiw. Il y a deux problèmes avec le billet de [...]
August 30th, 2009 at 10:15 am
[...] to be purely causal because there may be an omitted variable bias, IQ for example. Paul Krugman and Matt Yglesias both attack Mankiw and point to graphs showing that income matters for college completion and [...]
August 30th, 2009 at 11:04 am
. I think a great many of the “I just don’t test well” crowd arise from those who aren’t very intelligent who can, with enough effort, fake it.
When “faking it” is indistinguishable from “really” being able to do it, it’s hard to say that this has much relevance.
There’s a natural admiration in the US for people who are perceived to be naturally talented, so there’s always a bit of disdain for people who are upfront about “working for it,” because this is considered “cheating.”
People who say “I just don’t test well” are not the workaholics. Generally they’re people who lack attention/discipline/etc. but get by on charisma.
the evidence that studying for the SAT’s does any good is pretty weak.
What? People can and do study for the SATs and it does boost their score. True story! It’s a knowledge test of things like vocabulary and some math problems that is aided with knowledge of geometry and trigonometry, as well as a flair for making educated guesses. It’s not rocket science.
August 30th, 2009 at 11:41 am
There’s a natural admiration in the US for people who are perceived to be naturally talented, so there’s always a bit of disdain for people who are upfront about “working for it,” because this is considered “cheating.”
Well, it is cheating. The SAT, fundamentally, is a measure of intelligece, and any attempt to claim that you can prep or study into your way into higher intelligence seems, to me, highly dubious.
I would hae thought my SAT score to be worth a lot less if a lot more people could simply study their way to it, with enough effort. What’s the point? To study harder than the next guy? Hells no.
August 30th, 2009 at 11:43 am
It is sort of like the mediocre kid from a crappy school who studies and works his way to a 4.0 and Harvard or Stanford Law.
By my standard that would be cheating. Harvard Law should be for smart people, not just hardworkig ones.
August 30th, 2009 at 1:32 pm
[...] UPDATE: Matthew Yglesias [...]
August 30th, 2009 at 4:15 pm
[...] purely causal because there may be an omitted variable bias, IQ for example. Paul Krugman and Matt Yglesias both attack Mankiw and point to graphs showing that income matters for college completion and [...]
August 30th, 2009 at 5:16 pm
Mankiw’s affiliation, with the American Enterprise Institute, is grounds alone for discounting what he asserts.
August 30th, 2009 at 6:29 pm
By my standard that would be cheating. Harvard Law should be for smart people, not just hardworkig ones.
That was the justification that Harvard and Yale gave for shutting Jews out of admissions: “exceeding one’s potential” was considered cheating, to say nothing of being declassé– as the truly deserving do not need to work hard.
August 30th, 2009 at 7:09 pm
What’s the point? To study harder than the next guy? Hells no.
I just want to add that this attitude pretty much sums up most of what’s wrong with American culture: a disdain for “real work” and the expectation that wearing a tie and a nice suit entitles you to success while turning down your nose at the hungry people who are working for it. If you keep up like this, you’re just going to get your ass kicked by the people who are willing to work at it, and you’re going to cry that it isn’t fair, since you believe you’re entitled by dint of the station in life you believe yourself to be part of. And they will kick your ass. Though they may say to your face how they never really need to work that much and it just comes naturally, just so you won’t feel bad and will be comfortable with your personal failures.
August 30th, 2009 at 9:04 pm
“there is no particular eveidence that it is iq determining-genes that we are inheriting.”
ol’ one eye,
You need to see some of the twin research by UCLA Neuroscientist Paul Thompson:
“It is clear that intelligence is at least partly genetically determined. This was supported by the discovery in 2001 that the volume of the brain’s grey matter, made up of “processor” cells, is heritable and correlates with certain elements of IQ (Nature Neuroscience, DOI: 10.1038/nn758). The amount of white matter, which provides the connections between these processors, has since been shown to be heritable too (Journal of Neuroscience, vol 26, p 10235).
Now it seems that the quality of these connections, which is governed by the integrity of the protective myelin sheath that encases them, is also largely genetic, and correlates with IQ.”
http://www.newscientist.com/article/mg20126993.300-highspeed-brains-are-in-the-genes.html
August 31st, 2009 at 12:56 am
You’ve used defense as a verb. Very awkward. It’s most commonly used as a noun. “Defend” is the verb.
August 31st, 2009 at 4:24 am
[...] to be purely causal because there may be an omitted variable bias, IQ for example. Paul Krugman and Matt Yglesias both attack Mankiw and point to graphs showing that income matters for college completion and [...]
August 31st, 2009 at 5:43 am
Brian
By some do you mean the one paper Thompson published on the brain imagery of 10 sets of Finnish identical twins in 2001? Thompson’s lab now has images from over 700 sets of twins but has not published anything on the heritability of grey matter in 8 years. That 2001 paper is generally cited for positively correlating gray matter volume with intellectual functioning not the heritability of IQ.
You may be interested in another twin study – Turkeimer 2003
- which demonstrated that the proportions of IQ variance attributable to genes and environment vary nonlinearly with SES.
August 31st, 2009 at 1:08 pm
Mankiw made a rather mundane, a rather obvious and rather correct point that the NYT chart leaves out important variables. It’s silly to see how bent out of shape Yglesias and the commenters are. And it doesn’t get you anywhere to strawman Mankiw by saying that he thinks test scores are purely a function of innate ability.
August 31st, 2009 at 1:59 pm
2) IQ-type intelligence (or “g”) is a very strongly heritable trait, it is inherited to about the same degree as height. In older teens and adults the heritability of IQ-type intelligence is about 60 to 80%, the other 20 to 40% is due to nonshared environmental factors (i.e. factors that are not associated with the home and parenting effects).
You know what is also a highly heritable trait? What language a child speaks, but that obviously has nothing to do with genetics and everything to do with what culture a child grows up in. The heritability of a trait alone is not a good predicator of how much of that trait is genetically determined.
To understand IQ you have to understand the Flynn effect, the worldwide phenomenon of IQ scores rising at a rate of about 3 point per decade for the past 100 years (though this rate is highly variable for different populations).
This means that 100 years ago people with the average IQ of 100 would have the equivelant to an IQ of 70 today, the legal cut off for mental retardation.
What this says to me is that either there was a massive upheavel of smart genes in the worlds genetic pool (unlikley) or that the results of IQ tests just don’t have that much to do with genetics.
August 31st, 2009 at 2:17 pm
People, the SAT math section does not just test simple knowledge–it tests ABILITY, period. The type of questions that appear in that section heavily test mental traits that clearly differ from person to person and which the more intelligent tend to possess in spades.
First of all, consider the fact that the math section is HEAVILY timed. There are about 60 math questions and you’re allotted a minute per question on average. The smarter you are, the more likely you are able to go through those questions faster.
Second, go back and flip through an SAT prep book and observe the nature of the math questions. Many of them take the form of a brain teaser.
http://www.pbs.org/wgbh/pages/frontline/shows/sats/art/doughnut.jpg
The question is: “In the figure above, what’s the greatest number of non-overlapping regions into which the shaded region–the doughnut–can be cut with two straight lines? In other words, how many pieces can you cut the doughnut into with two straight lines?”
That’s an IQ type question, and the SATs are replete with them. Also, the math section does test material learned in high school–but it uses that material to determine underlying ability. Thus, solving many questions correctly depends upon the ability to do mental calculation quickly, or the ability to PERCEIVE a connection. Hell, often it takes kids a minute to understand what the question is asking for in the first place–and say they succeed and it takes them two more minutes to choose an answer: they are now three minutes behind the person who is understanding and answering questions within in a minute, i.e, the high IQ kid, the kid who ends up in a top-ranked school.
August 31st, 2009 at 8:17 pm
An IQ type question than can easily be prepared for according to the same frontline documentary. And it(doughnut question) has nothing to do with math. It has nothing to do with aptitude. And it most certainly has nothing to do with merit. Unless you define merit as being coached.
From the same program cited above, the College Board and ETS repeatedly state the the SAT is not an IQ test. According to the College Board, the SAT now does not measure any innate ability. Wayne Camara, Director of the Office of research at the College Board told FRONTLINE that the SAT measures “developed reasoning,” which he described as the skills that students develop not only in school but also outside of school.
September 1st, 2009 at 11:09 am
If you’re the college board, would you *really* be eager to announce that the SATs is a disguised IQ test and lose business?
They’ve been peddling away from the IQ connection for decades now, going so far as to remove the word “aptitude” from the test’s name. But the test essentially remains the same: a measure of mental ability.
By the way, consider the source. Test-prep companies have ever incentive to promise that scores can be improved drastically.
September 2nd, 2009 at 12:01 am
So if it is in the monetary interest of the College Board and the review companies to insist the SAT is not an IQ test what is the incentive for people who insist that the SAT is an IQ test? Hmmmm………….
PS – most of the people in the documentary thought the verbal section was closer to an IQ test than the math section.
September 3rd, 2009 at 6:02 am
[...] qui a fait bondir Paul Krugman et Matthew Yglesias. Ils reprochent à Mankiw de laisser entendre que les différences de revenu aux Etats-Unis [...]