
Lifetime Earnings Are 40-50% Heritable - barry-cotter
https://link.springer.com/article/10.1007/s10888-019-09413-x
======
barry-cotter
> Using twenty years of earnings data on Finnish twins, we find that about 40%
> of the variance of women’s and little more than half of men’s lifetime
> labour earnings are linked to genetic factors. The contribution of the
> shared environment is negligible. We show that the result is robust to using
> alternative definitions of earnings, to adjusting for the role of education,
> and to measurement errors in the measure of genetic relatedness.

~~~
oli5679
There is extensive literature on twin studies that finds effects of roughly
this magnitude on a range of health/earnings/educational metrics. 40%-50%
genes 40%-50% random/non-shared environments and small impact of shared
environment.

[https://www.researchgate.net/profile/Bruce_Sacerdote/publica...](https://www.researchgate.net/profile/Bruce_Sacerdote/publication/228389297_Nature_and_Nurture_Effects_on_Children%27s_Outcomes_What_Have_We_Learned_from_Studies_of_Twins_and_Adoptees/links/55b62f1808ae9289a08aabb3.pdf)

~~~
evrydayhustling
So, they do this by comparing correlations in MZ (genetically identical) and
DZ (typical sibling genetics) twin outcomes. Doesn't that assume that the fact
of being DZ vs MZ does not itself create environmental (non-genetic) effects?
The identical twins I know face particular social pressures to respond to
their twin identity, which could drive towards outcomes that are more
correlated -- or not! But it seems weird to base a branch of literature on the
assumption that it's not. Is this addressed?

~~~
Symmetry
That's a reasonable sort of question but would you say that MZ twins are
treated differently enough to explain 40% of variation in earnings? If they
were all locked in cellars out of shame I could see that being the case but
that doesn't square with the identical twins I've known.

But it actually is addressed by other studies such as adoption studies that
show generally the same results. And, of course, there are potential problems
with adoption studies too. But wouldn't it be suspicious if every[1] method of
studying the problem we tried gives fairly close numbers but only because they
all happen to be biased by the same amount in the same direction?

[1]GWASes give lower numbers but we know that there are many sorts of genetic
interaction they don't cover so this is expected.

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niktezak
It would be valuable to try and reproduce these findings in a country like the
US or UK whose citizens have been found to exhibit much lower socioeconomic
mobility [1] whereas the Nordic countries (as well as Canada and Australia)
are known to provide much more mobility. I would be surprised if the results
held up unaffected.

[1]
[https://www.oecd.org/centrodemexico/medios/44582910.pdf](https://www.oecd.org/centrodemexico/medios/44582910.pdf)

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shusson
> we assumed ... that there is no correlation between genetic factors and the
> shared environment

I'm no expert, but that seems like the biggest issue. I mean the study says
that income is heritable, which by its very nature would affect the
environment that right?

~~~
timini
It will affect the environment of BOTH twins

~~~
gpderetta
Isn't that the point of the parent?

~~~
barry-cotter
You can estimate true heritability by comparing fraternal and identical twins,
both of which will have shared environment, but identical twins are identical
genetically and fraternal ones are as similar as any other sibling pair.

~~~
shusson
> You can estimate true heritability by comparing fraternal and identical
> twins

Can you explain this a bit more?

~~~
barry-cotter
[https://en.wikipedia.org/wiki/Twin_study](https://en.wikipedia.org/wiki/Twin_study)

> The classical twin design compares the similarity of monozygotic (identical)
> and dizygotic (fraternal) twins. If identical twins are considerably more
> similar than fraternal twins (which is found for most traits), this
> implicates that genes play an important role in these traits. By comparing
> many hundreds of families with twins, researchers can then understand more
> about the roles of genetic effects, shared environment, and unique
> environment in shaping behavior.

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nabla9
I suspect that genes that affect immune system play big role in the heritable
intelligence just like immune plays role in the environmental factors
affecting IQ.

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ep103
> The contribution of the shared environment is negligible.

What does this mean?

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known
Doesn't Finland have
[https://en.wikipedia.org/wiki/Inheritance_tax](https://en.wikipedia.org/wiki/Inheritance_tax)

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leto_ii
Unfortunately I can't dedicate too much time to reading the article right now,
but did anybody understand how they managed to isolate the genetic vs
environmental components?

~~~
username90
You do it by comparing identical twins against fraternal twins and see how the
variance differ.

That way you have 3 variables, genes (identical twins have same genes,
fraternal twins just have similar), the home and parenting part, and all other
parts that aren't related to your parents at all. This study in particular
found that just the genes and the other factors were relevant, while the home
wasn't.

~~~
mrrrgn
While I think on the whole our society is very biased toward a Boasian view of
nature versus nurture: "give me a child and I can raise it to have any
personality and aptitudes via deliberate rearing techniques." I'm skeptical of
some of the conclusions being drawn from this study.

Environment has not been entirely separated out here it seems. And while a
comparison of fraternal and identical twins detangles things somewhat it
doesn't completely.

My intuition is that a person's personality and aptitudes (around 50%
heritable according to many studies) can help them to take advantage of their
environment in certain ways. So it's not that environment doesn't matter at
all. It's just that people with varying attributes will leverage their
environment in different ways, leading to different outcomes.

It would be even more interesting to me to see the personality profiles of the
children compared against their future earnings. My guess is there would be a
strong correlation since personality -> interests -> career choices.

Then it would just so happen that identical twins have similar personalities.
Leading to the results we see here.

Admittedly I'm hopeful that if we could figure out the correlation between
personality and environment maybe we could shift our focus away from the
unhealthy extremes of 100% nurture (leads to children being pushed by their
parents to fit into a mold that may not suit them) and 100% nature (genetic
fatalism leads to apathy and hopelessness). Instead what if we took a child's
natural gifts and personality profile into account and tailored their
environment to maximize their potential within those constraints? Seems like a
more hopeful and useful path.

~~~
barry-cotter
> While I think on the whole our society is very biased toward a Boasian view
> of nature versus nurture: "give me a child and I can raise it to have any
> personality and aptitudes via deliberate rearing techniques." I'm skeptical
> of some of the conclusions being drawn from this study.

Boas was wrong.

> Genetic Influence on Human Psychological Traits

> There is now a large body of evidence that supports the conclusion that
> individual differences in most, if not all, reliably measured psychological
> traits, normal and abnormal, are substantively influenced by genetic
> factors. This fact has important implications for research and theory
> building in psychology, as evidence of genetic influence unleashes a cascade
> of questions regarding the sources of variance in such traits. A brief list
> of those questions is provided, and representative findings regarding
> genetic and environmental influences are presented for the domains of
> personality, intelligence, psychological interests, psychiatric illnesses,
> and social attitudes. These findings are consistent with those reported for
> the traits of other species and for many human physical traits, suggesting
> that they may represent a general biological phenomenon.

[http://humancond.org/_media/papers/bouchard04_genetic_influe...](http://humancond.org/_media/papers/bouchard04_genetic_influence_psychological_traits.pdf)

~~~
mrrrgn
I absolutely don't disagree with you. Personality traits and aptitudes are
strongly inherited, along with some genetic randomness and some environmental
conditioning. What I don't like is full on genetic determinism. Human beings
transmit both genes AND memes for a reason. As sentient beings we inhabit two
universes. The one made of atoms and the one made of thought and ideas.

Compare, say, humans and ants.

Ants seem to have a ROM of sorts: software embedded in genes and immutable
within a single organism's lifetime. They only inhabit the world of atoms.

Humans have a ROM to cover basic functions but also writable memory. We can
change our behaviors within a single lifetime and then if that wasn't cool
enough we can also TRANSMIT those behaviors without genes via the world of
thought and ideas (language).

We ought to never forget that. Fatalism binds us too strongly to the physical
world. It's a bad path that leads to nihilism (struggle against nature is
futile), cruelty (everyone deserves their lot in life since if they were
capable of more they would have achieved it), and despair (self-actualization
is impossible, I am an automaton).

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tkyjonathan
I have a feeling that this is going to include things like IQ and then we will
get into a big racist mess.

~~~
H8crilA
It almost certainly is explained in good part via IQ. IQ is strongly heritable
and explains quite a bit of earnings variance.

Not sure what's racist about that though. It's just reality, facts about
humans.

~~~
journalctl
Discussions about IQ (which isn’t a particularly useful metric anyway, for
various reasons) tend to veer into racist territory because people end up
associating wealth and success with IQ, and since a disproportionate amount of
wealth in America is controlled by whites people, and since minorities are
more likely to live in poverty, this causes some people to suggest that those
specific minorities have lower IQs or something. Basically, it brings up old
racial stereotypes of non-whites not being as intelligent as whites, which is
a very old, racist canard.

~~~
jacobreise
"because people end up associating wealth and success with IQ, and since a
disproportionate amount of wealth in America is controlled by whites people,
and since minorities are more likely to live in poverty, this causes some
people to suggest that those specific minorities have lower IQs or something"

This is really not how IQ testing is done. Rather than guessing about
correlations in the environment to IQ and working backwards to come up with an
estimate for IQ, generally IQ tests are administered.

~~~
JoeAltmaier
But notoriously with cultural bias. Questions about 'which of these tea-
service items goes with the other?' and so on.

~~~
jacobreise
It isn't true that IQ tests contain questions about tea-service items or
yachting or other culturally biased questions.

Raven's Progressive Matrices [1] is an example of a test that doesn't depend
upon knowledge of tea service items.

[1]
[https://en.wikipedia.org/wiki/Raven%27s_Progressive_Matrices](https://en.wikipedia.org/wiki/Raven%27s_Progressive_Matrices)

~~~
JoeAltmaier
Presuming of course that test-taking, geometric drawings, mathematical
concepts are not cultural either...

