Is human intellect on the downward slide? (debunked) | Hacker News Reader

Is human intellect on the downward slide? (debunked)

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22 pointsvectorbunny21 comments

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.

I think that's a funny movie (and just brought it up at work last week), but I don't actually believe we're getting dumber. I think there is a societal "anti-smart" sentiment right now (nerd, geek, etc), and that the media portrayal of idiocracy is more entertaining (or perhaps more lucrative - Jackass, Swamp People, etc).

The premise was amusing, but the movie itself was not really worth writing home about IMO.

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.

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.

I'm not expert, but is this something actually could happen?

I assume that if two dumb people mate rather than all of their offspring being even dumber there is at least an equal chance of the offspring being brighter than the parents?

It was a completely fictional comedy movie, not a documentary.

To answer your question though, anything could happen. However, the premise of the movie isn't very sound (again, it is fiction). You are correct. A child can be brighter than both parents.

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

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

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

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

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

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.

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

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.

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...

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?

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.

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...

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://online.wsj.com/article/SB1000087239639044403240457800...

http://www.guardian.co.uk/books/2012/sep/28/are-we-getting-s...

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

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.

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

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