
Is human intellect on the downward slide? (debunked) - vectorbunny
https://theconversation.edu.au/is-human-intellect-on-the-downward-slide-10841
======
pawn
I never thought the movie "Idiocracy" would be on-topic here, but for those
who haven't seen it, it makes a similar argument. It starts off by saying
smart people have less children than dumb people, and extrapolated for long
enough, everyone is an idiot. Decent movie for those of you who haven't seen
it.

~~~
meaty
Quite funny film. The premise appears to be happening around me (in London,
UK) as the social housing and unemployable people have lots of children
compared to non-social housing people. I'm not talking small amounts more -
we're talking 6-8 children versus 1-2. In my children's school, 26 out of 32
children in the class are entirely dependent on welfare, and this is a nice
bit of London apparently.

However, I feel people _are_ getting stupider. It's not because of breeding
but because they contract out all but menial thought to technology. Long since
gone have the days where any mental effort was to be expended on performing a
task.

~~~
yardie
This is probably a local anomaly. If most people were on benefits than the
government wouldn't bring in enough revenue to sustain it. I'd also point out
that London is an anomaly in itself. Middle-class people also receive benefits
because everything is so expensive and everything is so damn expensive because
basically everyone is receiving some form of benefits.

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danielbarla
The relation between IQ tests and intelligence aside, I thought that the
"downward slide" argument was at odds with the Flynn effect (a significant,
upward trend in IQ scores over the past century or so):

<http://en.wikipedia.org/wiki/Flynn_effect>

~~~
zerostar07
Though it would be hard to attribute that to natural selection.

~~~
danielbarla
Sure, but put another way, the article is making predictions which don't seem
to fit the data.

~~~
chm
But he's measuring gene expression, which is not a subjective science.
Measuring IQ, on the contrary, is.

~~~
a_bonobo
Crabtree is measuring nothing, his arguments are just based on assumptions,
there is no gene expression data in these two papers.

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rsheridan6
If it was true that agriculture has caused a substantial slide in
intelligence, remnant hunter-gatherer populations, and populations that were
hunter-gatherers until recently, should be the smartest people on earth. For
example, Native Americans (at least the ones from tribes which weren't too big
on agriculture) should be smarter than most other ethnic groups in America. As
far as I know, that's not the case.

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ojbyrne
I highly recommend the book "A Farewell to Alms" that gets a mention in the
article.

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ams6110
I'd say it's true that there is now less selective pressure on the human
species than there used to be, but 3,000 years is a short period of time on
the evolutionary scale. Doubtful that any significant effects have resulted
yet.

~~~
rsheridan6
3000 years is 100+ generations. That's a lot of time for evolution. Russian
researchers turned wild silver foxes into tame pets in far fewer generations
than that:
[http://www.brighthub.com/science/genetics/articles/46555.asp...](http://www.brighthub.com/science/genetics/articles/46555.aspx)

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alexro
Isn't it what counts in the wild is adaptability? And looking at intellect as
a by-product of adaptability, if the world and our society changing in a
direction where intellect is no longer needed - say technology is taking over
our daily decisions - it is natural to trade intellect for a better
technological fit?

~~~
chm
What mechanism do you propose to account for the selection of "technologically
minded" people? Restricting yourself to North-America, what are the
evolutionary pressures exerted on human populations that justify such
evolution?

Not so easy.

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tokenadult
Thanks for submitting this. This is a much-needed response to a story that had
IMMENSE uptake from news sources all over the world. I'll recycle some
electrons here from a rather quiet recent thread discussing another response
to Gerald Crabtree's claims

[http://www.popsci.com/science/article/2012-11/are-people-
get...](http://www.popsci.com/science/article/2012-11/are-people-getting-
dumber-one-geneticist-thinks-so)

that wasn't part of the first wave of gee-whiz stories based on Crabtree's
press release, but which actually interviewed other knowledgeable experts to
provide perspective on the claims. Reading the Popular Science article "Are
People Getting Dumber? One Geneticist Thinks So" linked above, originally
submitted to Hacker News by user omnisci

<http://news.ycombinator.com/item?id=4811697>

and reading the article kindly submitted here by vectorbunny helps to clear up
some of the misconceptions sparked by the many articles based on Crabtree's
press release.

What I've noticed about this widely covered story is that Crabtree has
certainly mastered the Science News Cycle

<http://www.phdcomics.com/comics/archive.php?comicid=1174>

by making a press release that has had uptake from dozens of news outlets. But
none of those news outlets seem to have reporters on staff who are competent
to judge the genetics issues involved, or who even know sources in the
Behavior Genetics Association. (The article kindly submitted here has better
sourcing and analysis than most of the previous articles based on the same
press release that I have seen, as author Rob Brooks has actual expertise in
the subject, and took care to think through Crabtree's arguments before
rushing to print.)

I had earlier shared links to some of the first stories on this issue with
friends in the Behavior Genetics Association (I'm part of the Facebook group
for the association). Gerald Crabtree has some interesting institutional
affiliations and previous accomplishments,

<http://www.hhmi.org/research/investigators/crabtree_bio.html>

but he is not leading researcher on the genetics of human intelligence. One of
the Behavior Genetics Association scientists commented, "I don't know why
Crabtree is wasting his time writing about this when he can do such great
scientific work."

I have met most of the researchers who are currently active in research on the
genetics of human intelligence at a meeting of the International Society of
Intelligence Research and at events sponsored by researchers in the Minnesota
Twin Families Study in my town. They don't take Crabtree's approach to these
sensitive issues.

Another comment already posted here mentions the writings of James R. Flynn.
Readers interested in more detail about historical trends in human
intelligence are well advised to read James R. Flynn's new book Are We Getting
Smarter? Flynn's book deals with much more recent times (just the last
century) but has the advantage of being based on actual IQ tests.

<http://www.amazon.com/dp/1107609178>

[http://www.cambridge.org/us/knowledge/isbn/item6835805/Are%2...](http://www.cambridge.org/us/knowledge/isbn/item6835805/Are%20We%20Getting%20Smarter/?site_locale=en_US&?site_locale=en_US)

[http://online.wsj.com/article/SB1000087239639044403240457800...](http://online.wsj.com/article/SB10000872396390444032404578006612858486012.html)

[http://www.guardian.co.uk/books/2012/sep/28/are-we-
getting-s...](http://www.guardian.co.uk/books/2012/sep/28/are-we-getting-
smarter-review)

Flynn is very well respected among behavior geneticists as a "truth-seeker"
for his careful research work.

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Daishiman
Considering how recent the study of epigenetics is, I doubt we can make a
meaningful analysis of this. Nutrition quality has gone up incredibly in the
last century and its impact remains to be seen.

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Evbn
It was debunked via Reddit citations before the original article was posted on
HN.

