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Humans today aren't subjected to natural selection the same way we used to be.  In the early days of humanity, people with poorer vision or slower reflexes were more likely to end up being unable to find enough food to survive, or possibly becoming food for a saber-toothed tiger.  Today, though, the only things which frequently cause people to die before they can reproduce are disease and accidents, to which just about everyone is equally susceptible.  So it isn't initially obvious what, if any, selective pressures there are that still affect humans in the present.

Daniel Seligman, in his book A Question of Intelligence, points out a rather worrisome trend in this area.  According to several studies conducted over the past 30 years, fertility rates are negatively correlated with intelligence—meaning that people with low IQs tend to have more children, and have them sooner, than people with high IQs.  When you think about this, isn't entirely surprising that it's the case.  It's easy to imagine that people who have children as teenagers are less intelligent, on average, than people who wait until their 20s or 30s for it.  And because of the inevitable effects of natural selection, if people with low intelligence have a higher rate of reproduction than people with high intelligence, over multiple generations this will cause humans in general to become dumber.

With this in mind, here is this month's topic:  Should it be considered a problem that natural selection is favoring humans becoming less intelligent?  And if so, what should be done about it?

My opinion about the answer to this question is something that's changed over time.  Until around five years ago I was a Social Darwinist, meaning that I thought it was important for society to be structured in a way that encouraged natural selection.  As is pointed out by Mainstream Science on Intelligence, an article published in the Wall Street Journal and the psychology journal Intelligence with the signatures of 52 specialists in this area, intelligence is very strongly correlated with economic success—regardless of race or family background, more intelligent people earn more money on average than less intelligent people do.  As a Social Darwinist, I thought that if there weren't any government handouts for low-income people, perhaps they wouldn't have enough money to raise families, and natural selection could be made to favor people with high intelligence rather than the opposite.  While this system seems unkind to the people who would end up losing out under it, the idea is that this cost would be outweighed by the overall benefit of humanity becoming smarter.

I still think that something like this would be worthwhile if it were possible, but what I've realized over the past five years is that it isn't.  The problem is that there simply is no such thing as "not enough money to raise a family".  When one looks at people in third-world countries who earn less than five dollars a day, this doesn't prevent them from having kids—if anything, they end up having more children because their children can help them to try to earn money.  So if anyone is hoping to create a society where intelligence correlates with reproductive success, getting rid of handouts to poor people is not the way to do it.

A second way to try and accomplish this is using eugenics, where the government gets directly involved preventing certain people from reproducing, but that has its own set of problems.  The simplest of them is just that historically, no government has ever been able to exert this kind of power without eventually starting to abuse it.  The most obvious example of a failed attempt at eugenics is Nazi Germany, in which an attempt to make sure only "genetically superior" people could reproduce gradually morphed into a system of persecution based on race, religion, political preference, and other traits which had nothing to do with what eugenicists normally care about.  Eugenics policies of the United States in the early 20th century didn't stray quite this far from their original purpose, but even in the U.S. people were occasionally sterilized against their will for no reason other than their race—as though the people running this system had completely forgotten the distinction between a difference in average intelligence between races, and the idea that every member of a certain race has lower intelligence.

However, even if it were possible to implement a eugenics policy while avoiding this kind of corruption, there's also a much more fundamental problem with the idea.  In the early 20th century, it was widely assumed that it would be easy to identify which genetic traits we should want natural selection to favor in humans:  intelligence, physical endurance, good eyesight, and so on.  But the reality is far more complex than this, because what genes make one individual more "fit" than another is almost always subjective, even when it comes to traits such as intelligence that are seemingly without a downside.  As Gregory Cochran and Henry Harpending point out in this paper, the same genes which code for higher IQ also place people at greater risk for a number of hereditary diseases.  And as a result, in at least one population of humans where natural selection has favored intelligence especially strongly, these diseases have also become much more prevalent than they are among the rest of humanity.  Even if a government were able to successfully implement a eugenics policy that favors intelligence, it would inevitably lead to a higher rate of these diseases also.

So if eugenics is a bad idea and Social Darwinism isn't possible, then what can be done about the current selective trend towards lower intelligence?  Fortunately, there's a third possibility which might become a reality soon.  As scientists identify the functions of more and more genes in the human genome, it's becoming possible for parents who use in vitro fertilization to specify which genetic traits they want their offspring to have.  As stated in this article, it's already possible for prospective parents to make sure the embryo they implant doesn't have certain genes which would result in an elevated risk for cancer, so it soon might also be possible for them to make sure it has genes for above-average intelligence.  And since these decisions would be made on an individual embryo-by-embryo basis, parents would be able to avoid the specific combinations of genes which result in hereditary diseases.

This solution isn't without its own set of pitfalls.  At the moment, parents are only able to choose from a selection of embryos produced by their own eggs and sperm, but it's easy to imagine how far this field of "designer babies" could go.  Will parents one day inject non-human genes into their embryos, based on ridiculous fashions for kids with traits like bioluminescent hair?  Still, virtually every scientific advancement has its downside—such is the price of progress.

Agahnim
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:iconuximata:
uximata Featured By Owner Apr 13, 2009
The best thng you can do for any specie is leave it's genetic variability as vast as possible. Selection programs could easily take out usefull genes just because they are linked to "dumb" genes.
Also those historic events portrayed over there (nazy and us eugenics) are to fresh in folks memory, and any attempt to revive them (or something similar) would be simple bad P.R. for science.
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:iconkingtut98:
kingtut98 Featured By Owner Apr 12, 2009  Hobbyist General Artist
I'm hopeful that, even if people become genetically less intelligent, it'll balance out to some extent as a result of better education and availability of information. :shrug:
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:iconagahnim:
Agahnim Featured By Owner Apr 12, 2009
That’s what Seligman thinks, but it’s still kind of unfortunate. There’s a definite limit to how much of an improvement in IQ can be caused by improvements in education, since improved education only helps people who previously weren’t getting enough of it. For people who were already living up to their maximum genetic potential in this area, improved availability of education isn’t going to make them any smarter. So if over time people are becoming genetically less intelligent, but education is becoming more available, the overall effect of this will be that the IQs of people at the low end of the IQ spectrum will rise, but the IQs at the upper end of it will drop.

That’s what studies over the past few decades seem to have shown. Compared to the 1970s and 80s, the dumbest people alive today (in the United States, at least) aren’t as dumb as they used to be, but the smartest people aren’t as smart as they used to be, either. The variability of intelligence seems to have decreased.

The reason I think this is unfortunate is because the smartest people in any society tend to benefit that society more than the dumbest people tend to harm it. People who invent cures for diseases, or any other new technologies that improve the quality of human life, are almost always at the upper end of the IQ spectrum. So even if nowadays there are fewer people than there used to be who can’t do basic arithmetic, I don’t think that outweighs the downside of having fewer super-smart people.
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:iconsekele:
Sekele Featured By Owner Apr 12, 2009
What about laws preventing certain people from having too much children?

There are laws like this in China
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:iconagahnim:
Agahnim Featured By Owner Apr 12, 2009
Well, laws about that wouldn’t help with this particular problem unless they applied differently depending on people’s intelligence. And then there’s the same issue of whether the government would be able to regulate something like this without abusing its power.

China’s policies have a similar problem, although it’s not exactly the same. Since the government there discourages people from having more than one child, and everyone there would rather have a son than a daughter, pregnant women will often check the gender of their embryos and abort them if they’re female. After a few decades of many more male babies than females being born because of this, China now has a chronic shortage of women.

I can’t think of any examples of governments interfering in people’s reproduction without it leading to these kinds of problems.
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:iconsekele:
Sekele Featured By Owner Apr 12, 2009
well, there is still the factor that children from large families tend to die more often
and I'm not talking just about 3rd world countries

gangs, alcoholism, drugs, sexually transmitted diseases
all are things more likely to affect people with low intelligence
(you don't hear of a lawyer who would die during a boiler explosion while extracting moonshine)
They are more likely to get infected TBC or the plague than a inteligent person

Some might even argue that these lower-intellect people are in fact the right way to go, since they are much more resistant do to the selection based on physical toughness
Maybe intelligence is in fact a blind branch without a future
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:iconuximata:
uximata Featured By Owner Apr 13, 2009
"r" strategists have a lot of children and invest very little time and effort in them (what is being here called "dumb people"). It's common in creatures who live in adverse conditions and die early.
"K" strategists have one or two children and invest a lot on them, are common in safe or at least stable environments.

Neither strategie is better because both depend on the environment where they evolved in.
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:iconsekele:
Sekele Featured By Owner Apr 13, 2009
couldn't say it better my self
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:iconuximata:
uximata Featured By Owner Apr 13, 2009
thanks :)
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:iconsekele:
Sekele Featured By Owner Apr 14, 2009
:)
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:iconbladeswift:
Bladeswift Featured By Owner Apr 11, 2009
First and foremost, intelligence is an ambiguous term. IQ tests are only one way of assessing that value. Building off that supposition, intelligence therefore cannot even be described as an entirely genetic trait.

Given that the evolutionary process has always been a reaction to the environment, there is no defined goal that humanity, or any species, should be trying to attain.

Most importantly, governments have no ethical right to enforce such a policy.
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:iconagahnim:
Agahnim Featured By Owner Apr 11, 2009
I probably should’ve been clearer with what I meant by “intelligence” in this post. What IQ tests measure is g, which is the common factor to all types of intelligence. Since all areas of mental ability are positively correlated with each other, it’s possible to use factor analysis to determine the cause of that correlation, which is what IQ tests do. That’s what the article I linked to was describing as having a strong effect on income level.

If you like, I can link you to several articles about the heritability of g (measured as the heritability of IQ), but to start with here’s Wikipedia’s article about it. Variation in IQ is around one-quarter environmental, and three quarters genetic.

There obviously isn’t any universal principle that says we should want humans to become more intelligent, but from a practical standpoint, I think it’s hard to argue with the fact that its effects are beneficial. In addition to income, intelligence (that is, g) is positively correlated with law-abidingness, so more intelligent people tend to commit fewer crimes. It’s also positively correlated with lifespan, probably because more intelligent people tend to make fewer bad decisions that are likely to shorten their lives. So just from the perspective of wanting to improve the quality of human life, I think it’s completely reasonable to think of intelligence as something valuable.

Although obviously, we need to be careful not to inadvertently increase the occurrence of the genetic diseases that are caused by some of the same genes which raise IQ. And I already stated that governments evidently don’t have the ability to do this properly.
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:iconsinande:
Sinande Featured By Owner Apr 12, 2009
"Beneficial" in what ways, and to whom? A more intelligent humanity might invent more technology and develop economy, society, everything in certain ways (I can't really imagine any other benefit from more intelligence), but I don't think that's necessarily "beneficial", at least not without qualifications.

First, there is always the bottom segment of society that doesn't get many of the "benefits" because they can't afford them. I don't think it's possible to eliminate (relative) poverty, no matter how much you "improve" things, although that may just be the cynic in me.

Second, how do "improvements" in whatever aspect of life actually benefit humanity on average? In my entirely subjective opinion, the only true indicator of that is some measure of "happiness". I seriously doubt the average American is happier than the average Amazonian native before Europeans started taking over their habitat. I see this as an evolutionary arms race of sorts between standards of living and our expectations of them.

Also, this might be the cynic coming out again, but will development benefit us in the long term? So far, the long term consequences seem to be freaking huge global issues, and nothing guarantees that any amount of IQ will solve them before we take a major plunge.

And, related to the first point about the bottom tiers:

I'm still not convinced that we have a good enough hold on the causal relationships here to confidently say that the trend you mention will dumb down humanity. I bet you that it's not just people with a lower IQ, but people at the bottom of society, who churn out children on a conveyor belt. And that raises the question, are they down there because they are dumb, or is it the other way round, or is it different for every country/region/ethnicity/religious group/whatever? If/where the causal arrow mostly points from poverty to low IQ, all we can say is that that society will remain a pyramid, and that's neither a big surprise nor cause for alarm. Some poor people have always risen higher.

This correlation/causation/confounding variables problem connects to the crime issue as well - and I also wonder if the crime~IQ correlation holds between populations, too.

[BTW, I partly read, partly skimmed the heritability of IQ article. You make it seem like that 3/4 heritability means a lot - but most of the article is dedicated to explaining why it's far too complicated to be characterised by a single number or even a range of estimates. The meaning of heritability isn't a simple and straightforward issue, and this seems like a prime example.]

(Also, how old is this trend you mention? If it's been going on for ever and ever, then it doesn't seem like it's making humanity dumber... I seem to recall average IQ has been on the rise since they invented IQ tests.)

OK, that turned into a random jumble of semi-related musings. I'll shut up now.
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:iconagahnim:
Agahnim Featured By Owner Apr 12, 2009
I definitely agree that raising everyone’s IQ wouldn’t get rid of poverty, since you’re always going to have a bottom 10% of the income spread, and they’ll always be unable to afford certain things that other people can. But I think there are some improvements resulting from intelligence which are completely objective, rather than just being a matter of comparison to people with lower intelligence.

Lifespan is one example. If more intelligent people tend to make choices that are more conducive to a long life, is there any reason why everyone being more intelligent would prevent that? I don’t think there is. As pointed out in this article, more intelligent people are also better able to invent new technologies. The benefits of most new technologies aren’t restricted to the people who invented them, so I don’t see why this is something that would be different if everyone had more of this ability.

Which direction the arrow of causation points between low IQ and low income is something I’ve talked about a lot at CF, if you remember that. Here’s one thread where we talked about it, if you remember: [link] . To put matters in a nutshell, one of the best indicators that low IQ causes poverty (rather than the other way around) is that when a person with low IQ is born to a wealthy family, they still end up not earning very much money once they’re on their own. As pointed out in the interview with Abigail Thernstrom, this is one of the reasons why affirmative action hasn’t been able to cause a long-term increase in the income of black families. On average, black students from families that earn over $70,000 per years are still doing worse academically than white students from families in the lowest income bracket, and as a result, any economic gains made by their parents don’t carry over to the next generation.

There’s a pretty good article from earlier this year here that describes the current state of research on the heritability of certain traits, including intelligence. The interesting thing about this is that it’s from the New York Times, which is one of the news sources that was attacking James Watson for what he said about this topic a year and a half ago. But now, even they seem to be willing to acknowledge that it’s primarily hereditary.

I’m not sure how long the selection for lower intelligence that I’ve described has been going on; Seligman suggests it’s been around 50 years, but not significantly than that. What’s strange is that although IQ scores have gradually risen over time (via the Flynn effect), SAT scores have steadily dropped. Seligman seems to think this is because of what I described in response to Kingtut98, where improvements in education are raising the IQ of the bottom half of the bell curve, while the IQ of the top half gradually drop. In his book The g Factor, Arthur Jensen also suggests that improvements in technology and nutrition have gradually reduced the number of people who suffer from mental retardation, which would also raise the IQs of people at the bottom of the bell curve. If the bottom gets raised enough, that would raise average IQs even if IQs at the top are falling.
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:iconsinande:
Sinande Featured By Owner Apr 13, 2009
On SAT scores: has education in the US really improved? That's a very important factor there that I can't just assume without evidence.

BTW, I don't question that IQ is highly heritable in the populations studied. I just wonder what that means. Since heritability is the proportion of phenotypic variation explained by genetic variation, high heritability can either mean important genetics or unimportant environment. I can't recall what the Wikipedia article says exactly, but doesn't it say that the human race has been sampled very poorly to see the bigger picture here? That what we know about the US and a few other countries doesn't say a lot about humanity in general?

[Incidentally, we'd expect traits under strong directional or purifying selection to show low heritability unless the selection pressure is very recent (which may be the case with IQ, though, if your 50 years is correct).]

It's a funny coincidence that I just had an intro lecture on behavioural genetics today. One of the examples was a study of the heritability of educational achievement in post-WWII Norway. Long story short, the equalisation of the educational environment (IIRC, the abolishment of private schools) resulted in a huge increase of heritability in men but not in women. There seems to be a massive amount of complexity around the heritability of traits like intelligence that can't simply be expressed in a few percentages.

Heritability and arrows of causation in a nutshell: in light of studies like this Norwegian thing, I highly doubt any of the IQ issue can be put "in a nutshell".

Anyway... Despite all appearances, I don't want to get into the murk of IQ genetics again, and probably the most relevant question in my above jumble of ideas was whether progress = improvement. I'm not so sure about "objective" improvements as you seem to be, and the longer life you mention is not an end unto itself; it doesn't automatically make people happier. Of course, you are free to regard something other than conventional fitness or happiness as improvements (and I'm free to think that makes no sense =P)
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:iconagahnim:
Agahnim Featured By Owner Apr 13, 2009
The thing it’s important to remember about SAT scores is they only represent the upper half of the IQ bell curve, because people only take the SAT if they plan on going to college. The decline in SAT scores is another trend reported by several studies cited by Seligman’s book, but that and an improvement in education aren’t necessarily contradictory. Better availability of education is mostly benefiting the lower half of the IQ bell curve, which isn’t something that can be seen by looking at SAT scores.

Most of what I’ve read about the way IQ heritability works (Jensen, Seligman, and numerous online articles) is that genetics determines a person’s potential IQ, but they need the right environment in order to live up to that potential. So if a person with a lot of genetic potential lives in an environment where they don’t get enough nutrition or intellectual stimulation, their IQ will end up not being particularly high. (Although this effect is a lot stronger during childhood than in adulthood.) On the other hand, if a person doesn’t have much genetic IQ potential, things like education and nutrition won’t be able to raise their IQ above a certain limit.

What this means is that how heritable IQ is depends on the environmental conditions in the place where you’re measuring its heritability. In countries that have problems with malnutrition and lack of access to education, environment is going to make a big difference in IQ scores. In Europe and the United States, on the other hand, almost everyone can get an education and enough to eat, so the heritability of IQ is a lot higher. Likewise, IQ is much more heritable at higher socio-economic levels than at lower ones, because at high socio-economic levels just about everyone can live up to their maximum genetic potential, whereas at lower levels the environment interferes with it a lot more.

If you’re interested in this topic, I think you really ought to read Arthur Jensen’s book The g Factor. Most people I know who follow this topic regards that as the best book that exists about it.
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:iconsinande:
Sinande Featured By Owner Apr 14, 2009
"If you’re interested in this topic, I think you really ought to read Arthur Jensen’s book The g Factor. Most people I know who follow this topic regards that as the best book that exists about it."

I don't think I'm interested enough to read a whole book, especially when I already have half a book store to read. (Yes, I know, why the hell am I here then? I guess it's time I retreated to less Important topics :giggle:)
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