August 9, 2011

Guardian: "Intelligence tests highlight importance of genetic differences"

From The Guardian:
Intelligence tests highlight importance of genetic differences 
DNA study links variations in intelligence to large numbers of genes, each with a small effect on individual brainpower 
Genetic differences between people account for up to half of the variation in intelligence, according to a study of more than 3,000 individuals.

Here's the abstract:
General intelligence is an important human quantitative trait that accounts for much of the variation in diverse cognitive abilities. Individual differences in intelligence are strongly associated with many important life outcomes, including educational and occupational attainments, income, health and lifespan. Data from twin and family studies are consistent with a high heritability of intelligence, but this inference has been controversial. We conducted a genome-wide analysis of 3511 unrelated adults with data on 549 692 single nucleotide polymorphisms (SNPs) and detailed phenotypes on cognitive traits. We estimate that 40% of the variation in crystallized-type intelligence and 51% of the variation in fluid-type intelligence between individuals is accounted for by linkage disequilibrium between genotyped common SNP markers and unknown causal variants. These estimates provide lower bounds for the narrow-sense heritability of the traits. We partitioned genetic variation on individual chromosomes and found that, on average, longer chromosomes explain more variation. Finally, using just SNP data we predicted ~1% of the variance of crystallized and fluid cognitive phenotypes in an independent sample (P=0.009 and 0.028, respectively). Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence.

64 comments:

eh said...

"...That we display such genetically influenced variation in intelligence across our species further hints at how important cultural, as well as biological, evolution has been to the human story."

My emphasis. I guess he had to say that (whether it makes sense or not given the preceding context).

Not that there aren't such influences. But then the question 'Which influence is predominant - cultural or genetic?' suggests itself. Oops.

Anonymous said...

Seems pretty important if it holds up.

Anonymous said...

So it should be possible to predict average differences in intelligence between races, as well as variance within each race, from genetic data.
Robert Hume

Anonymous said...

What about the Flynn effect? Methylation?
Robert Hume

Kiwiguy said...

Heh @ some of the comments to the article:

"Could we have DNA samples of London rioters?"...

"I suspect that the looters are missing a few relevant genes."

Anonymous said...

Steve -- Thanks for showcasing this study. Just when I start to think it's not worth coming here anymore, you come up with a gem.

Anonymous said...

Let's see how long it takes the government grant whores of the scientific community to admit that this is settled science. I predict that only emeritus faculty will openly praise and discuss this result.

Anonymous said...

"Could we have DNA samples of London rioters?"...


And those in Philly too.

Nanonymous said...

So it should be possible to predict average differences in intelligence between races, as well as variance within each race, from genetic data.

In theory yes. From this work, no. It was done exclusively on Scottish and English individuals. Chances are good that a large set of genes with small effects will be different in people from other races.

Anonymous said...

I refer to a topic near this one on this blogspot "Rick Perry is a Quick Learner". Is not Perry a sort of "nodal point" and a "vocal point" within a network of close advisers with very very high "g"? As such, what DIRECT relevance would his IQ have to his mental ability to be Governor. Or stated differently--Is it not time to seek to measure small group "g" generated among those tightly knitted in a shared purpose? It is of some relevance to note here that George Bush (the "g" lesser one ) was reported to have had a live "ear microphone" so he could be cued if he lapsed out in the face of a difficult question in some public forum.

Anonymous said...

This whole article is definite 'crime think'. I am surprised to see it in the Guardian. I wonder what effect the riots have on their willingness to print it?

Somebody's going to wake up in a couple weeks from their temporary bout of sanity and say, 'I printed What?

nooffensebut said...

The imprecision of the media’s language and the compartmentalization of the researchers’ foci will give the masses the false impression that this study says IQ is only 51% genetic. Here’s what The Guardian said:

“They found that 40% of the variation in knowledge (called "crystallised intelligence" by the researchers) and 51% of the variation in problem-solving skills ("fluid-type intelligence") between individuals could be accounted for by the differences in DNA.”

Here’s what the study said:

“Despite the fact that no specific genetic variants have been robustly associated with human intelligence, apart perhaps for APOE at older ages, our results show for the first time that a substantial proportion (40–50%) of variation in human intelligence is associated with common SNPs (minor allele frequency > 0.01) that are in LD with causal variants.”

In other words, common differences in point mutations were the only genetic differences addressed in this study. The authors admitted that additional differences could be due to SNPs with lower minor allele frequency and those “not well covered by the commercial SNP arrays.” They do not even mention the possibility that gene expression elements could also contribute to IQ narrow-sense heritability. They place that heritability estimate at 60%, but Need et al found a principal component heritability of 88% for the Cambridge Neuropsychological Test Automated Battery, which is supposed to cover a number of cognitive functions like memory and executive function.

It seems like GWAS authors do not wish to acknowledge a role for gene expression because such research belongs to the lowly and outdated world of candidate gene research (because GWAS can only study SNPs). Hence, a GWAS like Viding et al tells us that aggression has no individual important genes, while Dr. Phil runs tests on guests for the “warrior gene,” predictably leading to bitching and moaning from genetics bloggers.

Luke Lea said...

"...That we display such genetically influenced variation in intelligence across our species further hints at how important cultural, as well as biological, evolution has been to the human story."

I haven't read the article yet but my interpretation of this statement is not that contemporary cultural differences influence differences in intelligence today but rather that over many thousands of years in the past cultural differences have driven biological differences; in other words populations with different cultural histories will also have different biological profiles, including intelligence. History changes wiring.

Douglas Knight said...

How does this differ from earlier GWAS studies? Older studies identified lots of genes, none of which replicated. If they don't explain why the earlier studies failed, why should we trust this study? (Maybe they do address this, but the abstract implies that there were no earlier studies.)

Yes, it's good that they were able to predict IQ in a separate sample, but only 1% of the variance. Those p-values for the 1% don't sound right to me.

How can they explain 40-50% if they haven't found the genes, but only have SNPs in linkage disequilibrium? Everyone who has these genes happens to have characteristic SNPs?

Maybe the linkage disequilibrium SNPs explains why other studies weren't replicated. One should expect different GWAS to point to different SNPs. But if the second study directly asked whether a SNP in the first was predictive, it should replicate. As far as I know, they fail even this test.

Anonymous said...

And so it begins...

Kylie said...

The left will be all over this like stink on sh!t.

We already have the insanity defense ("No sane person would have committed such a horrific crime.") to excuse all wrongdoing by the left's favored victim classes. To this will be added the stupidity defense ("No intelligence person would have made such a stupid mistake.") for any mis- or malfeasance on the part of the left's dumb little darlings.

Instead of allowing things to shake out as they will, time, money and effort will be wasted on compensating the stupid for the great injustice of their having to live in a world of people more intelligent than they are. Even better, most of the goodies will, in fairness and now backed by science, be lavished on NAMS.

And of course, the left will continue to sneer openly at the less intelligent members of the upper classes and claim that such dummmies don't merit places in the Ivy League or at Oxbridge. At the same time, calling dumdums from the lower classes stupid, dumb, unintelligent, etc. will swiftly become as taboo as is any non-laudatory reference to the race of non-whites now.

Oh, what fun we're going to have.

P.S. Yes, I know the money's running out. I'm not sure they do. If this were the Titanic, we'd be heading for the life boats and they'd be rearranging the deck chairs in some inclusive, vibrant arrangement.

Joseph said...

A comment by JLOV after the Guardian article was wonderful:
Aug 09, 2011
JLOV says:
"There seems to be lots of misunderstandings about this study and the science related to it...
- Heritability refers to the proportion of trait variation between individuals that is explained by genes. If the heritability of IQ is, say, 50%, it does NOT follow that 50% of your IQ is determined by genes and 50% by environment or culture. Heritability indicates the extent to which differences between individuals in a population are due to genetic differences. Thus, if a population consists of genetic clones, the heritability of differences in IQ or any other trait between them is 0 percent (because clones are genetically identical)...
- This new study indicates that 40-50 percent of variation in intelligence can be explained by genetic differences. However, as the authors say in their paper, this establishes only the lower bound of the heritability of intelligence. Twin and family studies indicate that the heritability of intelligence is as much as 80% in adults in the developed world. More studies are needed to discover all genetic sources of IQ variation....
- All forms of intelligence are intercorrelated in a population. This means that people who are good at math tend to be good at, say, learning foreign languages, too, while those who are bad at one thing are usually bad at other things, too. This is what is referred to as general intelligence. There are also specific, narrower types of intelligence, but they are less important than general intelligence..."

Anonymous said...

OT, but we're finally getting some pictures from the riots...or of the people who are cleaning up after them, anyway.

Wonder what the primary difference between the rioters and the civic-minded would be.

Anonymous said...

But remember, even if genes account for ~50% of intelligence while environment/culture accounts for the remainder, in practice, the genes will end up accounting for nearly the entire difference in intelligence and/or test scores.

The reason is simply that we don't live in environments controlled by outsiders. We choose our own environments. That means that the lucky child born with good IQ genes very likely will also grow up in a house with two parents, lively conversations, an emphasis on education, etc. The low IQ kid likely will grow up with one parent, little interaction and some suspect role models.

It's the same reason that athletic people like to work out and play sports, while nerdy people don't. Yes, if you forced the nerdy kid to work out and play sports, he'd get better - up to a point. But because he doesn't enjoy working out or playing sports and realizes that he'll never improve enough to compete with the naturally athletic people, he chooses to spend his time doing things and being around people that he enjoys.

Those intelligence genes - on most occassions - will put people in environments that fit the intelligence levels.

Therefore, you don't genes to be responsible for 100% of the IQ difference. Fifty percent is more than enough.

Anonymous said...

"I suspect that the looters are missing a few relevant genes."

What relevant genes are the Brits (and Whites in general) missing that allow them to create that multi-racial environment in the first place which is detrimental to the well-being, safety and future survival of their people?

Anonymous said...

How soon before I can order tests for these genes from private companies, say, 23&me?

Anonymous said...

I can't get past the paywall, but I worry the result may be reflecting ethnic and class differences, with the real power of the technique being less. Also I wonder how closely related these people were, which matters for the detection of rare variants.

Jim O said...

By my count, this paper has 32 authors. Is that typical of articles in this journal, or is it that they hope there is safety in numbers?

Anonymous said...

Genetic differences between people account for up to half of the variation in intelligence, according to a study of more than 3,000 individuals.

This was already known, wasn't it?

Changing peoples genes once they are born is difficult, while changing the "other half" of the equation is easy by comparison.

Anonymous said...

Not that there aren't such influences. But then the question 'Which influence is predominant - cultural or genetic?' suggests itself

There's no easy answer to that. Perhaps no single answer. The advantage of the West over the East seems to be culural rather than genetic, while the advantage of the West over Amer-Indians msy be both genetic and cultural. And there are numerous other permutations.

kurt9 said...

This is quite good for the Guardian, which is the most far-left of the U.K. newspapers.

Thursday said...

Personality too seems to have a significant heritability, but similarly the number of genes involved seems to be huge.

JerseyGuy said...

Steve,
When the heck are you going to comment on the Britain riots??? I've been checking your blog every hour!

Anonymous said...

Steven nothing on the UK riots yet??

Anonymous said...

I guess that it may not yet be possible to predict racial differences if he can only predict 1% of the variance with known SNPs. The rest is explained by the "unknown causal variants" with which the SNPs are in "linkage disequilibrium".
Robert Hume

Anonymous said...

Economist Debates: This house believes that immigration is endangering European society.
http://www.economist.com/debate/debates/overview/210

NOTA said...

On the contrary, it takes intelligence to reason out that, with the police busy fighting rioters far away, there's probably nobody left to respond if you and your buddies bust out some windows and steal some stuff from the nearest store. And hey, who doesn't like new clothes, shoes, and electronics?

Truth said...

JerseyGuy said...
Steve,
When the heck are you going to comment on the Britain riots??? I've been checking your blog every hour!

8/9/11 12:28 PM


Anonymous said...
Steven nothing on the UK riots yet??

8/9/11 12:32 PM

There are too many white guys involved.

Anonymous said...

The reason is simply that we don't live in environments controlled by outsiders. We choose our own environments.

We don't chose the environment we are going to be born into.

That means that the lucky child born with good IQ genes very likely will also grow up in a house with two parents, lively conversations, an emphasis on education, etc. The low IQ kid likely will grow up with one parent, little interaction and some suspect role models.

Thus illustrating that you don't understand genetics at all. It is not "very likely" that a child born with good genes will have parents with those genes.

Having "good genes" DOES NOT mean that you were born to parents with "good genes". And having parents with "good genes" DOES NOT mean that you wll grow up in an environment conducive to fostering your intelligence. If such were the case we would be ruled by an hereditary aristocracy.

Anonymous said...

This means that people who are good at math tend to be good at, say, learning foreign languages, too, while those who are bad at one thing are usually bad at other things, too.

I can't say that I've ever noticed this in real life. There are very few polymaths. Most people who are highly intelligent in one area tend to be quite stupid in other areas. Academics, for instance, are famous for this. So are musicians.

Anonymous said...

"What relevant genes are the Brits (and Whites in general) missing that allow them to create that multi-racial environment in the first place which is detrimental to the well-being, safety and future survival of their people?"

In hard times, hard men seek military victory and dominance.
In time, wealth and power breeds more opportunities and spheres for higher values and ideals. Gradually, the elites wanna believe that their power is premised on justice than naked power. So, kings claim 'divine right' and aristocrats embraced 'noblesse oblige'. Partly, their power and wealth made them more complacent about possible dangers. Their children, who were born into power and privilege, took power and wealth for granted. For them, power and wealth were not enough. They wanted to feel culturally and morally superior. And so, they fell under the sway of certain intellectuals, activists, and artists. And they sought to morally ground their wealth and power by associating it with moral causes. Nature of moral causes change over time. Since end of WWII, it's been anti-racism, philosemitism, Afrophilia, and homophilia.

So, the elites of Europe, due to a mix of complacency(from their high status)and moral narcissism, decided to use their power to turn EU into a kind of rainbowtopia.
As for the masses, your average Brit teen is heavily into rap culture and trash culture; they think and act like porn actors, and they have nothing to aspire to.

Kylie said...

"On the contrary, it takes intelligence to reason out that, with the police busy fighting rioters far away, there's probably nobody left to respond if you and your buddies bust out some windows and steal some stuff from the nearest store. And hey, who doesn't like new clothes, shoes, and electronics?"

I would call that intelligence, not animal cunning. When my intelligent but naive dog with a stick my dumb but cunning dog wants, cunning dog prances around in a "C'mon, let's play!" way, causing my naive dog to drop the stick and follow her. Cunning dog then drops all pretense of wanting to play, races back and grabs the stick.

And it's not accidental, I've seen her do it repeatedly, always with the same results.

My naive dog is far more intelligent than my cunning dog. But she continues to be bamboozled by her.

Just like the UK government and the rioters/looters.

Kylie said...

Oops.

My response to the comment "On the contrary, it takes intelligence to reason out that, with the police busy fighting rioters far away, there's probably nobody left to respond if you and your buddies bust out some windows and steal some stuff from the nearest store." should have been:

"I would call that animal cunning, not intelligence."


But I think I actually typed, "I would call that intelligence, not animal cunning."

The first statement is the one I intended to make.

Kylie said...

Oops in my comment of 3:02 p.m., I wrote,

"I would call that intelligence, not animal cunning."

But what I meant to write was,

"I would call that animal cunning, not intelligence."

Anonymous said...

can't say that I've ever noticed this in real life. There are very few polymaths. Most people who are highly intelligent in one area tend to be quite stupid in other areas. Academics, for instance, are famous for this. So are musicians.

If you're good at math, likely you would also be good at foreign languages *if you put in the time to learn them.* No one is saying that studying math is going to make you wake up one day speaking italian, that's just stupid.

-osvaldo M.

Ivy League Bastard said...

an anon said:

>>"even if genes account for ~50% of intelligence while environment/culture accounts for the remainder, in practice, the genes will end up accounting for nearly the entire difference in intelligence and/or test scores." <<

No. Within whatever class of statistical models was considered by the study (be it realistic or not) the non-biological but hereditary effects you're talking about are already accounted for where they write proportions like 50 percent.

The correct argument would work the other way round. That is, having 51 percent of mental performance predictable genetically could represent 40 percent of direct genetic influence on brain function, plus 11 percent of environmental effects predictable from one's genetics (through its correlation with parents' IQ, culture, economics, etc). In addition to the 49 percent of environmental effects not predictable from one's genetics that would, in this hypothetical example, make "51 percent genetic" mean "40 percent biological and 60 percent environmental".

Anonymous said...

If you're good at math, likely you would also be good at foreign languages *if you put in the time to learn them.*


Neither here not there. The point is that most intelligent people are intelligent only in one narrow sense. And they not only are not terribly intelligent in other ways, they frequently are unusually unintelligent in other ways.

We call such people "liberals" in the US. They usually have college degrees, and they usually believe all sorts of preposterously stupid things which would make the supposedly non-intelligent working classes laugh.

catperson said...

The reason is simply that we don't live in environments controlled by outsiders. We choose our own environments. That means that the lucky child born with good IQ genes very likely will also grow up in a house with two parents, lively conversations, an emphasis on education, etc.

None of those things have any influence at all on a person's IQ by the time the reach middle age when the effects of shared environment completely vanish. g is a physiological variable that appears uninfluenced by culture, psychological experience or intellectual stimulation of any kind.

It's the same reason that athletic people like to work out and play sports, while nerdy people don't. Yes, if you forced the nerdy kid to work out and play sports, he'd get better - up to a point. But because he doesn't enjoy working out or playing sports and realizes that he'll never improve enough to compete with the naturally athletic people, he chooses to spend his time doing things and being around people that he enjoys.

You've fallen for the meme that the brain is like a muscle. The brain is not like a muscle. Mental exercise does not appear to make us smarter the way physical exercise makes us stronger. Instead intelligence is more like height, influenced only by genes and nutrition.

The only way I could see the environments we choose affecting our intelligence is if a genetically low IQ person decides to spend all his time consuming drugs and alcohol, while high IQ people abstain from substance abuse. But the effects of substance abuse probably contribute only a tiny percentage to IQ variation.

catperson said...

Neither here not there. The point is that most intelligent people are intelligent only in one narrow sense.

That's not true at all. Anyone who is super successful in life has to be capable in multiple areas. For example Bill Gates is not just brilliant at computers, but also gifted at recognizing business opportunities, hiring the right people etc. It's very rare that you'll find someone who is a genius in one area, who is below average in most other areas.

Statsquatch said...

Douglas Knight,

Unlike most GWAS studies this one does not try to find an association with a single SNP and IQ. They fit a model with IQ as a function of a random effect of 599K SNPs and estimate the associated variance components. The same method was applied to SNPs and height in an earlier paper.

Anonymous said...

Anyone who is super successful in life has to be capable in multiple areas.

You're moving the goalposts. Being intelligent and being "super successful in life" are two very different things.


It's very rare that you'll find someone who is a genius in one area, who is below average in most other areas.

Einstein was a socialist. Newton, who wrote more on religion than he did on science, had some very kooky beliefs indeed.

And Bill Gates is not a genius.

Anonymous said...

Bill Gates is not just brilliant at computers


Wait .... Bill Gates is brilliant at computers? I suppose Henry Ford was a fantastic auto engineer as well.

catperson said...

And Bill Gates is not a genius.

He might not be a genius in the sense of contributing to science or the arts, but in terms of raw brain power, he runs circles around Einstein.

BrokenSymmetry said...

"Bill Gates might not be a genius in the sense of contributing to science or the arts, but in terms of raw brain power, he runs circles around Einstein."

W - T - F!

Pensive brahmin said...

"in terms of raw brain power, he runs circles around Einstein."

Please explain why I should take you seriously after this comment.

Pensive brahmin said...

On topic , this is a very interesting study, but I remember when ASPM and microcephalin were portrayed in a similar light and then went to bust.I prefer to wait and watch for more data on the specific genes among races and IQ.

Anonymous said...

I would have to object to Bill Gates not being a genius. He not only attended Harvard but was placed into Math 55 and received an A in the course. Math 55 is by far the most difficult undergraduate mathematics course offered. It combines courses that most math majors take such as analysis and abstract algebra in their junior/senior year and first grad school year into 2 semester freshman year course. Taking complex analysis in freshman year is extremely rare and considering the average IQ of Harvard and the rarity of the student, the students taking math 55 course probably has an IQ 4SD and over. Gates also published a paper on discrete mathematics, which was fairly noteworthy in computer science. So taking his merits both in academics and business, Gates is definitely a genius.

Engineer Dad said...

Yesterdays results published in Molecular Psychiatry and PubMed add further evidence that human intelligence is highly heritable and polygenic. It's summary states,

"Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence."

http://www.ncbi.nlm.nih.gov/pubmed/21826061

Since more and more evidence has shown intelligence is highly heritable, astute leaders wanting to increase their nations wealth and stability should immediately put in place immigration policies to retain the capable while discouraging the feeble while separating the talented from their neighbors and competitors.

Failure to make this effort should be considered negligence.

Anonymous said...

in terms of raw brain power, he runs circles around Einstein.

Both Gates and Einstein are reputed to have (had) an IQ of 160. You don't seem to be terribly well informed about the subjects you speak on.

Brian said...

Bill Gates had a perfect score on his SAT. I think it is fair to say he has both high verbal and quantitative intelligence. Limited creativity, but plenty of smarts.

Ivy League Bastard said...

>> "Neither here not there. The point is that most intelligent people are intelligent only in one narrow sense. And they not only are not terribly intelligent in other ways, they frequently are unusually unintelligent in other ways. " <<

That has nothing to do with intelligence. It is reflection of two facts: that specialization exists, and that people don't often win the lottery twice.

Great pianists are not great violinists, and vice versa, but general musical ability exists. Michael Jordan was not a great baseball player, but general athletic ability exists.

In the same vein, beauty queens and nuclear physicists are mostly separate populations. Sad but true!

catperson said...

Both Gates and Einstein are reputed to have (had) an IQ of 160. You don't seem to be terribly well informed about the subjects you speak on.

You're right. I should rely more on urban legends like you.

Ivy League Bastard said...

The Bill Gates / Math 55 story according to Paul Allen:

"I was decent in math, and Bill was brilliant, but by then I spoke from my experience at Washington State. One day I watched a professor cover the blackboard with a maze of partial differential equations, and they might as well have been hieroglyphics from the Second Dynasty. It was one of those moments when you realize, I just can’t see it. I felt a little sad, but I accepted my limitations. I was O.K. with being a generalist.

For Bill it was different. When I saw him again over Christmas break, he seemed subdued. I asked him about his first semester, and he said glumly, “I have a math professor who got his Ph.D. at 16.” The course was purely theoretical, and the homework load ranged up to 30 hours a week. Bill put everything into it and got a B. When it came to higher mathematics, he might have been one in a hundred thousand students or better. But there were people who were one in a million or one in 10 million, and some of them wound up at Harvard. Bill would never be the smartest guy in that room, and I think that hurt his motivation. He eventually switched his major to applied math."

Anonymous said...

I should rely more on urban legends like you.


It's nice that you can take time out from informing the world that "in terms of raw brain power, (Bill Gates) runs circles around Einstein" long enough to whine about "urban legends".

No subject on the net attracts more ignorant blowhards than does discussion of IQ.

Anonymous said...

Great pianists are not great violinists, and vice versa, but general musical ability exists.

Yeah, general musical ability does exist. And people who posses it do not, contrary to some opinions expressed here, typically have any unusual degree of ability in non-musical areas.

Or do you really want to argue that if Kurt Cobain had not gone into music, he could have become a scientist or economist or spoken eight languages or done something noteworthy in another field?

Ivy League Bastard said...

>> "Yeah, general musical ability does exist. And people who posses it do not, contrary to some opinions expressed here, typically have any unusual degree of ability in non-musical areas. "<<

Actually, music does correlate with other skills. The correlation is not extreme enough that a music genius is guaranteed to also be a master of physics, politics and business, but so what?

As discussed earlier, the reason that "unusual degree of ability" in one domain is not typically accompanied by unusual ability in other areas has nothing to do with music, IQ, etc. It is a result of (you, the anon(s)) setting "unusual ability" as a performance cutoff. There are statistical selection effects that follow from that, and you happen to have noticed one of them. It tells us nothing about intelligence, music, or anything else.

If you control for the selection effects by looking at, say, pianists only or football players only, then yes, there will still be a correlation between piano ability and ability to master other instruments (or languages), and between football success and athletic ability transferable to other sports (as well as non-athletic attributes transferable to the post-NFL career).


>> "Or do you really want to argue that if Kurt Cobain had not gone into music, he could have become a scientist or economist or spoken eight languages or done something noteworthy in another field? "<<

The argument is rather that he would have been more likely than Courtney Love to reach any given level of success in those fields.

catperson said...

Yeah, general musical ability does exist. And people who posses it do not, contrary to some opinions expressed here, typically have any unusual degree of ability in non-musical areas.

Straw-man argument. No one is suggesting that all mental abilities correlate perfectly; many mental abilities correlate very weakly. But all mental abilities correlate POSITIVELY. So a sample of musically gifted people (or people gifted in any other cognitive domain) should average above the 50th percentile in every other mental ability. Similarly, a sample of musically retarded people should average below the 50% in every other cognitive domain. These are only averages so exceptions would be everywhere.

TGGP said...

Steve Hsu discusses the study here.

Kevin J. Mitchell at GNXP doesn't think they established that IQ is polygenetic.

Dutch Boy said...

No surprise. Human beings are immensely complex and most of their characteristics are governed by a relatively large number of genes (i.e., there is no single IQ gene).