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July 27, 2006


It sounds like you're saying that a little intelligence is adaptive, but too much intelligence is maladaptive. It yields strange implications at the boundary lines of natural selection, I believe.

If we weren't on the cusp of practical genetic engineering, this would be a catastrophic problem. As it is it's just a big problem. I'm not a believer in a Vingean singularity, but I do think that extrapolating current trends for a century won't give you any idea what's actually going to happen.
Also, the historical record is kind of murky as to whether intelligent people have always had fewer children than the less intelligent. As I noted in a comment on a previous thread, the upper classes had more children surviving to adulthood than the lower classes (by a factor of two) a couple hundred years ago in germanic areas. And in general I expect that, prior to the invention of modern social safety nets, the very lowest ranks of society have typically done very poorly. Slaves, paupers and so on wouldn't have had large families.

And a quibble: you didn't show that the most intelligent men were most likely to have to pay for sex, only that they were the most likely to have done so.

As Bbart said, "...you didn't show that the most intelligent men were most likely to have to pay for sex, only that they were the most likely to have done so."

If smart people have *lower* sex drives, why conclude they are less desirable rather than voluntarily choosing less sex? Beginning and maintaining a sexual relationship takes effort and compromise. If a guy doesn't want sex that often, maybe he'd prefer to outsource his occasional needs to independent contractors.

There's one job that won't be going to India.

Each generation is about 1/10 of a standard deviation less intelligent than the previous.

That's the first I've heard of this. Have you mentioned it before? I thought that average IQs were increasing.

Are people of relatively high intelligence less attractive to the opposite sex, or are they simply less likely to find suitable partners due to the fact that they constitute a minority within the overall population? I think women, and often men as well, admire intelligence and find it somewhat attractive, but at the same time it presents a barrier of sorts.

People of average or below average intelligence may not be immediately less attracted to those of high IQ, but they soon discover that they 'don't understand' or 'don't have much in common' with their more intellegent counterparts. This also works the other way, as those of higher IQ find it difficult to form or sustain a relationship with someone they find dreadfully slow going in conversation, or baffled by seemingly simple problems. Hence, people of higher IQs find it harder to meet up with those of similar temperaments and interests. Except, I suppose, at MENSA meetings or Star Trek gatherings.

If I might use an analogy, I find Anna Kornakova a beautiful (though obviously vain) woman. The fact that she's a very talented athlete makes her more, not less attractive to me. On the other hand, would I really want to spend time sitting around with her discussing the finer points of topspin, lobs, volleys, and backhands? Well, no, but maybe lying around talking to her . . .

if high intelligence creates a survival disadvantage, how did the human race become so intelligent?

This presumes that intelligence progresses linearly and that the apex was achieved in the recent past. The underlying assumption is that there is a direct relationship between the modern notion of IQ and adaptive natural intelligence. I don't think this is demonstrable.

For how long has intelligence been decreasing?

About a hundred years, by my subjective estimate.

That's the first I've heard of this.

Never mind. I just read your July 2 post. I'm not sure I agree with your conclusion, though. You just assumed that that the gf component outweighed the gc component and ignored the fact that gc increases with age.

Another test would be to compare WORDSUM scores in a single age bracket across multiple years. When I do this, there's no consistent pattern. For 40-45, it peaked in 1990. For 18-24, it peaked in 1998, and 1976 and 2004 were the second and third best years. Granted, some of this may be due to fluctuations in the difficulty of the test, but it casts doubt on your explanation.

The Flynn effect, as I understand it, is due primarily to a tightening up of the left tail of the bell curve, as environmental improvements allow more people to realize their genetic potential. So you wouldn't see this at all in the SAT, which so tainted by sampling bias as to be practically worthless as a gauge of trends in intelligence in the general population.

Reminds me of Constantinople and the Byzantine empire.

It seems to me that a clearly confounding effect is that the amount of assortative mating happening in the US has been increasing across the 20th century and into the 21st.

A long time ago, intelligent people didn't go to college as much as they do now, and were forced, pretty much, to make do with the potential mates found near them.

These days intelligent (and not-so-intelligent) people criss-cross the country to go to college, and meet other intelligent and not-so-intelligent people.

Intellectual seggregation is happening at a faster pace now.

I've no doubt about the higher-intelligence/ lower-fertility trend you've identified--other people have found the same (including Murray & Herrnstein in The Bell Curve).

However, I do think there's a lot going on here. One is that IQ doesn't predict survival-to-adulthood/ multi-generational fertility as well as it used to (thanks to technical advances and welfare schemes), so the selection pressure in favor of IQ is less.

I think your theory that highly-intelligent people are less attractive seems plausible. I think that people whose phenotypes differ greatly from the median on almost any measurement are less attractive. I speak of personal characteristics here, not command of economic resources.

There have been dramatic demonstrations of how the "average" of many faces (photos) is more attractive than almost any one of them.

The fact that potential mates value access to resources more highly than many other considerations explains both why short, smart rich men can usually find mates, and why high-IQ men pay for prostitutes more often--smart men may have more trouble charming girls, but (thanks to those engineer jobs) less trouble hiring them.

Another factor is immigration. The US is importing a lot of low-IQ people. They drag down the average directly, and they compete with high-IQ locals for mating opportunities by substituting different exotic traits for IQ when attracting partners.

And an important factor is statistics. I suggest that people generally find mates of similar IQ most attractive. However, that still leaves many other dimensions of attraction on which each potential mate must be satisfied before he or she will, um, bond.
So despite educational, occupational, residental segregation, high-IQ people are simply less likely to find congenial partners than average-IQ people, because they find fewer candidates to choose from.

Mark Seecof says:

However, I do think there's a lot going on here. One is that IQ doesn't predict survival-to-adulthood/ multi-generational fertility as well as it used to (thanks to technical advances and welfare schemes), so the selection pressure in favor of IQ is less.

Actually, I don't think this is so.

We have created and are still creating a more complex society that more and more values the ability to control impulses, to read and understand complex instructions and wend your way through a complex maze of laws. Just look at all those guys in jail and ask which groups they predominantly belong too.

"Just look at all those guys in jail"

From a Darwinian perspective, the guy in prison who fathered several bastard kids is more "fit" for survival than a high IQ man without any children.

There are 2.1 million people in prison, and 1.5 million children of people in prison. These are the children the system knows about--I'm sure that the prisoners have more kids that they don't know about or don't tell the justice system about. Being a convict obviously does not prevent a person from spreading his seed.

Although men with long prison sentences have less opportunity to father children, there's no evidence that a short stay in prison harms a man's fatherhood prospects.

After the posts of the last few weeks, I wonder if there is any reason we should want the highest IQ people to reproduce, other than to counteract the low end and prevent them dragging down the average below a stable democratic level.

Because it looks like we make less money, are physically unfit, and don't like sex much, which is a good thing because no one wants to have sex with us anyway, even each other, without cash payment.

Perhaps if I stopped reading to my male fetus and resumed occasional drinking, I could increase his own paltry chances of reproducing some day.

Let me add a couple of things.

I think the inherited female preference for tall males likely reflects the selection pressure of economic preference over many generations. In much of the world for most of the time, variations in male height chiefly reflect the growing male's access to food.

(I find it instructive that nearly all the US-born children of my Vietnam-born in-laws are much taller than their parents. Why? Mainly diet so far as I can see, and perhaps some effect from a more salubrious childhood environment.)

Of course, taller males may offer other advantages, but there must be trade-offs, because male height over 7' is remarkably rare. Women prefer tall men, so if height were "costless" I would expect the usual arms-race to produce more very tall men.

As for the fertility of criminals in our society (of course I agree with everything our host wrote), I really think the lower fertility of non-criminals is partly due to the way we've organized society.

We levy stiff taxes and other impostitions (not even forgetting the cost of Veblen-type competition) on our more productive people, which is to say on the more intelligent. The taxes feed transfer schemes which enrich the less productive/intelligent. It certainly is not the only factor, and it may not be the single largest factor, but by diminishing the resources of higher-IQ people we almost certainly depress their fertility--and the opposite for lower-IQ types.

I'll even go so far as to remark on the side-effects of our "child support" laws. The child-support racket only threatens productive people. Many criminals have no wages to garnish. Quite proper fear of the child-support monstrosity discourages high-IQ males from both marrying and canoodling.

"Each generation is about 1/10 of a standard deviation less intelligent than the previous."

So why don't we see tests showing this? WORDSUM, Raven's, the SAT, etc don't seem to show large decreases. The past 100 years, 4 generations or so, should be enough to show something.

Well, that's the mysterious Flynn effect at work.
The verbal SAT has been dropping for a while now, though. I blame more TV and video games and less reading.

"I wonder if there is any reason we should want the highest IQ people to reproduce"

smart chicks are hot?

"This theory would explain why highly intelligent people are less attractive to the opposite sex compared to people of average intelligence. If people of average intelligence were predicted to have the most surving children, then favoring sex partners whose intelligence is above or below the average would lead to having fewer surviving children."

Um, yeah, but you're assuming the most desirable people have the most kids and that people want to have lots of kids. Lots of upper-middles have very few kids.

I am so sorry but I am still laughing!!! This is so funny. The sex drive has NOTHING to do with intelligence, nothing!

More intelligent people probably just know how to use birth control properly. They may have more self control, maybe they masterbate more often, but trust me, the drive it still there.

I do enjoy your blog!

I was thinking like Kathleen. But I checked the GSS and, unfortunately, there are no data on masturbation.

The SAT has been dropping. Raven's have been going up.

The verbal SAT is lower than it was in the 60s, yes, but it's been flat since the mid-70s. And the math SAT is the highest it's ever been.

source: http://nces.ed.gov/programs/digest/d05/tables/dt05_127.asp

Seems reasonable. All ya got to do is look around. Check.

Looks like the average SAT score decreased from 958 in 1966-67 to 910 in 1995-95. Before they made the test easier because scores were too low.

If intelligence fell 1/10 of a standard deviation in that time period (approx one generation) then 20 points of that 48 point drop is because genetic intelligence falling.

1 century is about 4 generations. That's 40% of a SD or 6 IQ points. That doesn't take us out of the range of countries where Democracy works well (actually, hard to say, it takes us into a sparsely populated range, with most countries well above or well below).

Assuming that environment can depress IQ and that historically average IQs were selected for, people with some IQ significantly under 100 should be most attractive. Current dysgenics is a move to restore equilibrium, compensating for modern medicine and nutrition.

Half Sigma says:

From a Darwinian perspective, the guy in prison who fathered several bastard kids is more "fit" for survival than a high IQ man without any children.

Sigh, a little knowledge is a dangerous thing.

The guy in jail's reproductive success is only improved if the kids he fathered survive long enough to reproduce themselves, and actually reproduce.

In regards to "safety nets and healthcare" encouraging dysgenic breeding:

The administration that provided for social welfare before the welfare state was the church. They encouraged fidelity and fecundity by all the social classes.

With the church's power waning, hedonism and casual sex is the rule of the day. Thanks to America's particularly poor public health system, sexually transmitted diseases that make women (assumably dumb women that make poor choices) infertile are rampant.


Also, the inability to stop eating may not be as deadly as famine but it still has a toll. Juvenile diabetes due to poor diet is rampant among the lower class and creates all sorts of pregnancy complications.

Maybe we should start world war 3 and destroy all industrialization. Let famine and diseases back to get rid of low IQ people. A natural eugenisis.

Mentioning the SATs have been dropping as being an example of dropping intelligence, by comparing a point in the 1960's and 1990's, is rather misleading as the academic trends have been showing that an increasing amount of the population is going to college and the test pool has been substantially increasing. Since there's a definite positive correlation between the probability of going to college and one's SAT score(See the graph in The Bell Curve), then the increasing pool would lower the average test applicant SAT score. Where 2% of the student population going to college taking the SAT may score somewhere around the 10th percentile in terms of populace's intelligence(Hypothetically), then when 30 percent of the student body goes to college, just by numbers alone, the average intelligence HAS to be lower then the 10th percentile(Especially since the high school drop-out rates have been decreasing) so a decrease in the average SAT score is rather unsurprising. Nevertheless, when more of the population is actually attaining post-secondary education, it could actually be argued that this SAT score decrease's basis may be actually increasing the population's average intelligence, as the RAVEN samples.

For me that is not ture I want someone with a high IQ and I want to have childred with a guy that have a high IQ. Because this might shock you I want my children to have his IQ and my good looks. Yes, I am consiter a beauty not a geek or a nerd. The reason why I would be saying this is my IQ is not high at all it is around 78. Pluse if I went out with every guy that ask me out I would have 20 boyfriends. So yea, that whay I say, "I want my children to have his IQ and my good looks."

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