Genes matter

What matters more: nature or nuture?  Here's a fantastic paper (pdf) that  gives an economic perspective.
Everyone agrees that there's a strong correlation between parents' socioeconomic status and that of their children in later life. But does this come from genes (wealthy parents have "good genes" that they transmit to their kids) or environment (wealthy parents encourage schooling and give children confidence to learn and get good jobs)?
To find out, the authors looked at the link between parents' years of schooling and childrens' years of schooling for children brought up by their biological parents, and those brought up by adoptive parents.
If genes were all that mattered, you'd expect the education of biological parents to affect children's outcomes whether they were adopted or not. If nurture were all that mattered, you'd expect biological parents' education to have no effect on the outcomes of adopted children.
So, what did they find? That biological parents' education mattered even for adopted children.
For adopted sons, an extra year of biological fathers' education added 0.12 years to their own education. This is over half the effect (0.2) of sons raised by their biological fathers. And it's bigger than the coefficient on the adopted fathers' education (0.08).  Biological mothers' education has twice the effect upon adopted sons' education as adoptive mothers' does.
What's more, the effects of biological fathers' education upon adopted sons' earnings are twice as big as the effects of the adopted father's education.
The message here seems to be that pre-birth factors (including genes) are more important than upbringing.   
And here's the punchline. The data come from Sweden, where the government has traditionally made more effort than most to raise the life-chances of people from poor backgrounds. Draw your own inferences. 

Comments

[Rob Spear]

So does that make racism cool again?

[Marcin Tustin]

Sweden has mostly eliminated advantages of social background? Or that the society is so open that able ancestors will rise as well as their children do, and vice versa?

[Matt Munro]

This isn't new. It's well established that inteligence has a strong heritability factor. It's currently estimated to account for between 40% and 80%. It's not PC so it's ignored.

[Recusant]

Of course part of Sweden's success in eliminating the discrepancies of social background is the policy of eugenics they indulged in for over forty years up until the seventies. The forcible sterilisation of over 62,000 women, primarily, but not always, for reasons of mental deficiency, will certainly help shift your averages.

[Matt Munro]

Social background has nothing to do with it -genes don't have class. Clever people tend to stay in education longer, marry other clever people and produce clever kids. Stupid people tend to stay in education shorter, marry other stupid people and have stupid kids. The Swedish correlation with "time spent in education" is therefore a correlation with parental intelligence.
"The Bell Curve" proved this yonks ago. Social engineering is a waste of time and money.

[Dave Hinton]

You've linked to a long list of papers, and I have no idea which one you're talking about. Could you link to the precise paper you're talking about, please.

[Amir]

Genetic differences are of huge, underrated significance. Here’s a great quote from Steve Sailer:

“Contrast the triumph of Japanese manufacturing with Japan’s near-total failure in the brutally competitive global market for celebrities. (A recent survey revealed that Americans believe the most famous living Japanese person is Bruce Lee, a dead Chinese guy.) It's the mirror image of African-Americans' undistinguished technological achievements versus their outstanding performance in producing media personalities.

Why? Japanese talents extend far beyond chopstick-handling to a set of extremely masculine intellectual skills. Tests show they tend to excel at objective abilities like mathematics and mentally manipulating 3D objects through “single-tasking” (focusing deeply upon a one impersonal logical problem). Blacks, on the other hand, are often better at typically feminine, more subjective cerebral skills like verbalization, emotional intuition and expression, sense of rhythm, sense of style, improvisation, situational awareness, and mental multi-tasking. Michael Jordan’s brain, for instance, enables him to anticipate his opponent's every move while simultaneously demoralizing his foe with nonstop trash-talking.”

Read it all:

http://www.isteve.com/wealth.htm

[Amir]

Rob Spear,

The implication of Biodiversity is that there is no such thing as a “superior race.” Why? Because different races are better at different things: there’s no such thing as a “racial hierarchy.”

Nature interacts with nurture.

[alexandre delaigue]

Is this really news? There are lots of such demonstrations in "the nurture assumption" and "no two alike" by Judith Rich Harris. The basic problem is the definition of "nurture", which (according to her) comes marginally from education and mostly from peer effects.

[MatGB]

Chris, wasn't going to trackback, because I did a very quick link/discuss on my personal journal, but it's drawn out some very interesting comments:
http://matgb.livejournal.com/185485.html

[dsquared]

I can't find the thing either, but did it have a control in for race? One of the well-established results is that in mixed-race kids in the UK, skin tone is a much better predictor of academic achievement than actual genetic makeup (ie, a dark kid with one black grandparent will do worse than a light kid with three).

[dearieme]

"Blacks, on the other hand, are often better at typically feminine, more subjective cerebral skills like": is that why I find American football so camp?

[lucinda]

that black/chinese thing was absolute drivel. is it suggesting that p diddy is a better dancer than darcy bussel? no- it's just individual skills and abilities. chinese people may be better at physical manipulation, but that's because they've been brought up using chopsticks.
also, this study is gibberish. it purports that the results are due to genetics, but the main factor is entirely non-genetic. How long you spend in education is not genetic, it's an enviromental factor, as anybody with a basic knowledge of science- or common sense- could tell you. no scientist will ever find the 'attended university' gene, because it doesn't exist. ergo, it can't be passed on to your children.
Intelligence, on the other hand, or ambition, or determination, or personality type- they're possibilities.

[Amir]

Lucinda,

Of course… no one here is endorsing genetic determinism. Except for a few neurological disorders, no behavioural trait is determined with 100 percent probability by the genome [or anything else].

But in saying this also, I am equally sceptical of those who "overemphasise" the role of environmental factors. Like all other animals, our species has been shaped by millions of years of natural selection. Natural selection works through genetic inheritance and variation. Genes for many physical and behavioural traits are inheritable. And because of recombination and mutation, animals within the same species differ in their genetic makeup. The same applies, mutatis mutandis, to human beings.

[Lucinda]

so, do grey cats differ significantly from ginger cats?

[chris]

Sorry folks, the original link was wrong - it's fixed now.
Carelessness is in my genes.

[Chris Bertram]

I find your gloss quite remarkable in the way that it contrasts with that given by the authors themselves:

You write:

And here's the punchline. The data come from Sweden, where the government has traditionally made more effort than most to raise the life-chances of people from poor backgrounds.

They write:

We should add that these results pertain to a relatively rich society with a well-developed welfare state. It is quite conceivable that, in a less developed country, the variation in post-birth
environment might encompass a range in which environmental impacts are larger.

In other words, in an environment where the impact of social differences is minimized, biological differences will loom larger than they otherwise would. But put like that, it is exactly what you'd expect, and does nothing to support the "social engineering is a waste of time" comments in the thread above.

[Matt Munro]

In other words all social engineering acheives is the supression and denial of human nature.
Even if you accept that "minimising the impact of social difference" is necessary, let alone desirable (and I don't) and created a society where everyone was educated at the same school, did the same job for the same wage etc etc they would still have different parents, different friends, different interests etc etc. Human beings are not idential robots, nature is highly variable and reacts differently to nurture, even when nurture is identical.

In terms of definition "nurture" is everything outside the self, it's all the "inputs". "Nature" is what you are born with. The output i.e behaviour is a function of the two.

[Matt Munro]

A great many people with more than a passing knowldge of science would disagree !

Of course there isn't an "attended university" gene but attendance at university requires aptitudes and abilities which not everyone posesses because they are inherited. If you send a toilet cleaner to university he will not come out a rocket scientist. Similarly, no matter how much I practice football I will never "bend it like beckham".
People who do not excell academically (genetic) do not tend to go to university (environmental). Do you think its a coincidence that as the % of people going to university has increased, the academic content of courses has been watered down and/or the drop out rate has gone up - if it was purely environmental no matter how many people went to university, they would all succeed at any course ??? Going to university is a symptom of intelligence, not a cause.
You've confused cause and effect -what you are calling "environemntal" is the visible manifestation of genetic endowment, not the "cause" of intelligence.

[Jack]

One general point is that if the nurture part of the comparison were optimal, only nature would offer any explanation and in general successful management of nurture will tend to make nature appear more important.

A more specific point: it isn't clear that they account effectively for the transmission of biological parental education to adoptive parental education although they admit it as a factor in the preamble.

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The vast majority of living organisms encode their genes in long strands of DNA. DNA consists of a chain made from four types of nucleotide subunits: adenine, cytosine, guanine, and thymine. Each nucleotide subunit consists of three components: a phosphate group, a deoxyribose sugar ring, and a nucleobase. Thus, nucleotides in DNA or RNA are typically called 'bases'; as a consequence, they are commonly referred to simply by their purine or pyrimidine original base components adenine, cytosine, guanine, thymine. Adenine and guanine are purines, and cytosine and thymine are pyrimidines. The most common form of DNA in a cell is in a double helix structure, in which two individual DNA strands twist around each other in a right-handed spiral. In this structure, the base pairing rules specify that guanine pairs with cytosine and adenine pairs with thymine (each pair contains one purine and one pyrimidine). The base pairing between guanine and cytosine forms three hydrogen bonds, whereas the base pairing between adenine and thymine forms two hydrogen bonds. The two strands in a double helix must therefore be complementary, that is, their bases must align such that the adenines of one strand are paired with the thymines of the other strand, and so on.

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So, what did they find? That biological parents' education mattered even for adopted children.