
Race, Genes, and IQ (1995) - huihuiilly
http://bostonreview.net/science-nature-race/ned-block-race-genes-and-iq
======
qiqing
It seems the key problem that incites controversy is that when geneticists say
"heritability," it doesn't mean what lay-persons think it means, and
sometimes, even professionals in the field get caught up in defending the
wrong arguments.

To the HN crowd, here's a simple but precise definition. Heritability is the
extent to which variability (e.g., the standard deviation) of a trait in one
generation can be explained by the variability of that trait in the previous
generation. Note that high heritability does not mean that the trait is
genetically based.

Fun fact 1: since most people are raised by their parents, religion and
political party affiliation are also highly heritable, but no one is
suggesting that there's a genetic basis for religion or political views.

Fun fact 2: number of fingers per hand is not very heritable. Since most
people who have a non-five number of fingers per hand acquired that trait non-
genetically (e.g., via an accident), the variability of this trait in the
population correlates very little with the variability of the trait in the
previous generation.

~~~
nordsieck
> To the HN crowd, here's a simple but precise definition. Heritability is the
> extent to which variability (e.g., the standard deviation) of a trait in one
> generation can be explained by the variability of that trait in the previous
> generation. Note that high heritability does not mean that the trait is
> genetically based.

> Fun fact 1: since most people are raised by their parents, religion and
> political party affiliation are also highly heritable, but no one is
> suggesting that there's a genetic basis for religion or political views.

You're wrong. There are separated twin studies; they rule out stuff like
"parents, religion and political party affiliation". There may in fact be some
other mechanism by which heritability works, but it would have to be physical,
and it would have to act in ways indistinguishable from genetics.

Also, there are plenty of people suggesting that people's religion and
political views have a genetic component.

~~~
tomhoward
An important question here are whether we're talking about immutable genetic
encoding vs genetic expression (sometimes more controversially known as
"epigenetics"), which is mutable via environmental stimuli, experiences,
beliefs, traumas, cultural influences, etc.

The follow-up question to that is the extent to which one's epigenetic state
at birth is determined during gestation and influenced by the mother's beliefs
and experiences (as well as the father's indirectly via the mother).

This would explain why some correlations are found in twin study results, but
also why those correlations are never close to 100%.

It would also explain the study results that suggest inheritance of patterns
like trauma/anxiety e.g., in descendants of holocaust survivors.

I'm fully aware this area is nascent and yet to be deeply researched, but
hypotheses exist that are plausible and potentially explanatory of phenomena
that are otherwise still unexplained.

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rbanffy
I always like to point out that, as IQ, ZIP code is also heritable. I lived
for about 49 years in the same city my mom lives.

~~~
henryaj
How many genes have we discovered that determine your ZIP code?

~~~
klyrs
Har dee har. Non-whites were forbidden from moving into many zip codes by law
until, IIRC, around 1958. Real estate agents kept enforcing those laws long
after they were struck down, and there are still tons of properties that have
"racial covenants" which forbid* the current owner selling to a non-white
buyer. And such neighborhoods change their composition very slowly.

So no, the causative effect is the reverse of your implication: there are many
well documented zip codes that significantly determine your genetics

* though enforcement of such clauses wouldn't stand in court today

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AlexTWithBeard
I find it interesting how the post was flagged even before the discussion
started.

Is it because the question of heritability of zip codes is too sensitive?

~~~
nikolay
Low IQ correlates with high flag activity.

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Schiphol
This article is from 1995.

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wiremine
Agreed the title should include the year of the article: 1995. It is reacting
to the book "The Bell Curve" which was published in 1994. The wikipedia
article is here:

[https://en.wikipedia.org/wiki/The_Bell_Curve](https://en.wikipedia.org/wiki/The_Bell_Curve)

TL;DR; White people are genetically smarter than black people.

(To be transparent: I'm a white father to a black daughter... the book is bull
shit IMHO)

That said: If you enjoy genetics, I'd recommend "A Brief History of Everyone
Who Ever Lived", which uses actual science and is much more recent:

[https://www.goodreads.com/book/show/30135182-a-brief-
history...](https://www.goodreads.com/book/show/30135182-a-brief-history-of-
everyone-who-ever-lived)

The author's style is entertaining and insightful, although a bit flowery. As
a reviewer on Good Reads mentioned "That was very... British."

~~~
sebastos
For anyone that's curious, the actual point of The Bell Curve is that modern
society's knowledge economy increasingly rewards IQ, so we should be careful
not to create a world that conflates "high IQ" with "good person", since you
don't really get to choose your IQ. Then it goes on to try and bolster the
case that picking winners based on IQ could have unforeseen negative
consequences. In that setting, there is a chapter that claims that this IQ-
centered culture would disadvantage certain races more than others, since
there are differences between average IQ when you divide people into groups
based on their race. The question of heritability arises because the authors
want to argue that these differences might persist for an arbitrarily long
time if they are not strictly environmental. To support this possibility, they
give their interpretation of the data on this topic: that the expressed IQ
differences are likely at least partially genetic.

The article OP posted argues that this is not a parsimonious explanation of
what we see. The author points out that heredity and genetic determination are
not synonymous, and reminds that there are a number of results that suggest
environmental effects can strongly influence group IQ. Further, we cannot de-
conflate the effects of passive vs. active covariance between environmental
and inherited effects. An example of the these two categories is the
difference between:

(Passive) "Children with high musical ability tend to be born into families
that will give their child lots of music lessons"

and

(Active) "Parents tend to give their children more music lessons if they
demonstrate high musical ability early in childhood"

where in both these cases an inherited trait (natural musical ability) created
a double-whammy environmental effect. The former is easier to control for, but
the latter requires a domain-specific hypothesis to isolate. (I'm not sure I
completely followed the article here, but this is the best summary I can
give.)

