Saturday, May 26, 2012

Education, IQ, and fertility

Reading some of Inductivist's work on fertility and political orientation among wealthy white women, I was struck by the following:
Education's effect is not the influence of IQ. Among this demographic, IQ is unrelated to fertility. The correlation between IQ and number of kids is .02--basically zero. Education's influence appears to be cultural.
I previously did my best to portray the strong, inverse relationship between educational attainment and fecundity in the US. The correlation is indisputable, but that, of course, does not necessarily inform us about causation. The fear of dysgenic dystopia in the future is usually premised on the notion that IQ, not schooling, and fertility run in opposite directions.

Inductivist's statement made me wonder how much IQ matters once education is taken into account. It's easy to conceptualize why contemporary education and procreation don't mesh well. Young men and women spend their most fertile years accumulating debt and squandering assets (if they have any to begin with). By the time they've graduated, established themselves in their careers, and fixed their personal balance sheets (if they ever manage to do these things, and increasing numbers of them do not), their biological clocks, especially women's, are past noon.

It's more difficult to do the same with intelligence. Popular culture does not particularly celebrate childbearing, but procreation isn't public enemy number one, either. The world-shrinking consequences of technological progress means there are more things than ever for intelligent people to pursue, of which having and raising kids is just one of an ineluctably growing many, and not a seemingly attractive or intellectually 'actualizing' one at that. But total fertility rates in the West were well above replacement for several decades after children had clearly become economic, time-consuming 'burdens' rather than an extra pair of hands to help on the farm. Intelligence and education are linked, often confusedly, in the public mind, but a plausible explanation is that more intelligent people tend to pursue more education, and end up having fewer children as a result.

Using the GSS, let's consider just that. In the following graphs, respondents are categorized into five groups* based on educational attainment and into five groups based on IQ as measured by wordsum scores. For contemporary relevance, only data from the last two decades are considered, and all respondents included are at least 35 years age to allow time for family formation to have occurred.

In the first graph, we see how educational attainment and fecundity relate among those of similar IQ:


So, among those who scored in the 0-3 range on the wordsum test (the real dumbs), those with less than a high school education (black bar), average just over three kids. Those real dumbs who graduated high school (brown bar) and those who spent some time in college without graduating (white bar), average about 2.5 each, the real dumbs with a bachelor's (yellow bar) about 1.75 kids, and those with post-graduate degrees (baby blue bar) 1.5.

For all IQ groupings, education is a strong predictor of fecundity. Even among the really smarts, obtaining a college degree reduces total fertility by 0.5. Among those of modest intelligence, staying in school means staying out of the delivery room. I'm sure there's a cute phrase like "Yale or jail" applicable here, but it's not coming to me at the moment (soliciting suggestions in the comments).


In the second graph, we see how IQ and fecundity relate among those of similar educational attainment:


The relationship here is considerably weaker. The effect of education on average total fertility rates among those of similar IQ is five times as large^ as the effect of IQ on average TFRs is among those of similar educational attainment. This is detectable in the latter graph by noticing how there is a clear decline in fecundity as we move up from one level of educational attainment to the next, but there is not much difference across the IQ spectrum among those of similar educational attainment.

While aware that it is an erroneous oversimplification to argue that the demographic transition in the West has been driven primarily by the increasing duration of formal educational attainment, the latter is strongly associated with the former. The more I look into it, the more difficult it becomes to think about the developed world's inverting age pyramid without considering educational romanticism.

We need methods to speed up the educational process, like self-paced coursework and subject-specific standardized testing (think AP tests for those in college) that allows autodidacts to receive credit as soon as they've demonstrated proficiency in a subject rather than after four inefficient months of spending three hours per week having it delivered to them at varying levels of effectiveness. Ideally, passing the bar would be the only requirement for practicing law and passing the CPA exam the only requirement for becoming a CPA. If this results in a perceived glut of lawyers and accountants, the respective tests can simply be made more difficult. While the relative value of high parental socioeconomic status will decrease and higher conscientiousness might as well, higher intelligence would be rewarded with more precision and young professionals would be able to get to work years earlier and with tens of thousands or hundreds of thousands of dollars less debt on their shoulders.

Necessity being the mother of innovation, here's to hoping the impending popping of the education bubble ushers in changes along these lines.

GSS variables used: AGE(35-89), BORN(1), EDUC(0-11)(12)(13-15)(16-17)(18-20), WORDSUM(0-3)(4-5)(6)(7-8)(9-10), YEAR(1990-2010), CHILDS

* Groups are mutually exclusive, so those who are listed as having graduated high school went exactly that far but no further. Obviously, those who have doctorate degrees also graduated from high school, but they are only represented in the "post-graduate" grouping here.

For IQ, respondents are broken up into five categories that come to roughly resemble a normal distribution; Really Smarts (wordsum score of 9-10, comprising 13% of the population), Pretty Smarts (7-8, 26%), Normals (6, 22%), Pretty Dumbs (4-5, 27%), and Real Dumbs (0-3, 12%).

^ Ordinary least squares standardized regression coefficients are (.16) for educational attainment and (.03) for intelligence as measured by wordsum score. My thanks to Inductivist for walking me through the process of how to determine these.


28 comments:

John said...

Interesting data. If Obama gets his way and everybody goes to college, fertility problem solved!

sykes.1 said...

Real dumbs with post-graduate degrees?

I know university standards have fallen, but it seems scarcely credible that read dumbs can do doctorates--even in the humanities.

But if real dumb is a social construct and educational standards are arbitrary cultural constructs, then I guess it is not only possible but to be expected.

Glad I'm retired.

PS. My bleeding heart left wife actually flunks people in her womens' studies courses.

Audacious Epigone said...

Sykes,

Less than 2% of real dumbs fall into this category, compared to more than 10% of the rest of the 35+ adult population. Also, it captures Master's degrees (hello education!) as well as those who do doctorates.

Noah172 said...

Among those of modest intelligence, staying in school means staying out of the delivery room. I'm sure there's a cute phrase like "Yale or jail" applicable here, but it's not coming to me at the moment (soliciting suggestions in the comments)

"State U or kid's poo"

"Post-grad or You're Dad"

"Senior year or Junior's here"

"Hit the studies or buy the Huggies"

"Degree a fable? You'll rock the cradle"

Anonymous said...

Consider the education that the most educated women actually have. It more properly could be termed indoctrination. The vast majority of the most educated women are educated in some squishy field of nonsense. Only a tiny fraction of the most educated women are nerdy science types.

Also, I have noticed among my smart and very educated fellow female friends is that the most confident ones are the ones who can walk away from the degree and career hype and choose to have more kids and spend more time with their families. I am talking women who are engineers, doctors, etc. Definitely not dumb. Disproportionally the more confident ones who don't desperately need social approval are able to walk away from it and devote themselves to what they really want.

Audacious Epigone said...

Noah,

Haha, well done! Every one of those is great. I really like #3 and #4, with #4 probably having greater utility since it's a little less specific and thus more generally applicable. Thanks for those!

bleach said...

I'm still at a loss as to how the education bubble can pop for as long as the government is still solvent--it seems more likely the lenders will just get a big bailout, or they'll make post-secondary ed "free", transferring the debt burden from the students to the government. College grads aren't having kids anyway so what do they care if future generations have to finance their extended adolescence at High School+?

Btw when did it become impossible for the bar or the CPA exam alone to get you a job? Did that change precede the overcredentialization of other fields, or follow it? Curious..

Good article

Audacious Epigone said...

Bleach,

The 150 hour rule has been around since I was an undergraduate in '06, but I don't know when it was first implemented (and it varies by state, of course). Five years and $XX,XXX to merely become eligible to take a competency test--what a racket, huh?

Jason Malloy said...

Last summer I boiled the evidence about IQ and fertility down to three conclusions:

1) Intelligence does not reduce fertility

2) Female education is the cause of lower fertility

3) Education lowers female fertility primarily by stemming unplanned pregnancies

Audacious Epigone said...

Jason,

Thanks. Consider this additional confirmation of the same.

Dan said...

Have you looked at they effect of religiosity on fertility when intelligence is held constant?

This strikes me as a very important question. It is well-established, I think, that religiosity is positively correlated with fertility. But what is the specific impact of religiosity on the fertility of the really smarts, averages and dumb specifically?

bgc said...

This kind of analysis cannot uncover THE relationship between IQ and fertility, since relationship is variable - relationship is contingent upon the specific cultural conditions.

We know this from the fact that the relationship (not controlling for education) is opposite in historical and modern societies; or in modern societies between Mormons and secular people.

We do know that high IQ people have had lower reproductive success over the past couple of hundred years - e.g.

http://charltonteaching.blogspot.co.uk/2012/02/convincing-objective-and-direct.html

and the factor of religiousness (with orthodox and traditional monetheistic religions, maybe others) is a major factor in fertility the modern world.

Also, if we are interested in evolution, we probably ought to focus on reproductive success.

RS was determined mostly by differential mortality in the past, but by differential fertility in the present:

http://charltonteaching.blogspot.co.uk/2011/05/child-death-and-demographic-change-and.html

And IQ is almost certain to affect mortality and fertility by different mechanisms, the direction and strength of which would presumably vary with conditions.

Ed Tom Kowalsky said...

Good post, AE. And I support your solutions to the education/fertility conundrum. But like all sensible solutions in postmodern America, yours doesn't stand a ghost of a chance. Hence, as long as disparate impact theory is accepted in courts of law, testing scores will never be allowed as a criterion for employability in discrete fields. Mushy, malleable, socially engineered criteria, such as college degrees, will remain as salients of employability.

rjp said...

Where can one take some of these Word Sum tests?

Audacious Epigone said...

Dan,

Great idea, I'll look at it.

BGC,

Does the Gregory Clark effect occur among contemporary Mormons in the US? If I've seen hard evidence of this, I've forgotten about it.

RJP,

Here it is--pretty simple. I suspect most readers here for whom English is a first language will ace it, which highlights the fact that the GSS doesn't give us much of a way to distinguish between someone with an IQ of 130 and someone with an IQ of 160+.

bgc said...

"Does the Gregory Clark effect occur among contemporary Mormons in the US? If I've seen hard evidence of this, I've forgotten about it."

I don't suppose anyone has looked for this directly - indirectly the Momrons have gone from being an artisan class group to a distinctly elite intellectual group in the space of half a dozen generations.

RS said...

Jason & others -
Do you think genotypic Conscientiousness is likely to be declining due to differential fecundity, even if genotypic IQ is not? After all, C should most likely be a strong determinant of educational attainment ; it could also alter fecundity through other avenues.

Jason, I think one of the grand old men (Lynn?) considers genotypic IQ to be declining within-race, but I am not certain of this. In any case I don't esteem your opinion less than his. So I would have to dissect both opinions if I wanted to attain to a view of my own. I don't think he necessarily thinks /phenotypic/ IQ is in decline within-race (he does seem to think phenotypic C is quite likely declining considerably, within-race).

I am also pretty sure that Danish hereditarian and immigration skeptic, Ny-something, considers (at least genotypic, if not phenotypic) IQ decline to be important -- it's in his paper modelling the future IQ of Denmark as a function of both racial change and within-race dysgenesis. But again I'm just noting his opinion, I don't necessarily claim that he is right.

RS said...

Here's the paper -- it's freely available -- Nyborg is the name.

Lynn (1996, p. 31) averaged the results of several early
studies, and found that [phenotypic] intelligence had declined two points per
generation.


Alas, it's not too clear what's going on there -- namely, is there some correction being applied for the Flynn effect? One would have to dig up the paper.

RS said...

Ah me, excuse me, I've been reading rather poorly -- most of all, not distinguishing very well between what people are saying about regressions, and what they're saying about correlations.

Jason says there is in fact an IQ-fecundity correlation (though he doesn't name a particular value):

1) Intelligence does not reduce fertility

There is a correlation, but it is only there because smarter people choose more schooling. And the causal factor is either the schooling itself or other personal traits that push people into more schooling but that are unassociated with intelligence.


I would sort of criticize this choice of words, but I appreciate that it's subjective -- anyway I see what you mean.

Comparable, but potentially more confusing, I think, is what AE says here:

Inductivist's statement made me wonder how much IQ matters [for fecundity] once education is taken into account.

Whether or not IQ is an immediate determinant of fecundity certainly matters, but I don't see how it matters at all for the question whether the Idiocracy thesis is true. In fact the Idiocracy thesis need not assert that IQ is a determinant at all, in any strong sense -- merely that it is a correlate. So I if I'm not mistaken there is some unclarity in AE's post, what with the allusion to Idiocracy.

Audacious Epigone said...

RS,

Maybe I'm oversimplifying, but if education, and not IQ, is 'determinative', then coming up with ways to keep people from spending 20+ years in school is likely going to have eugenic consequences.

Anonymous said...

I recall reading in the NY Times 15-20 years ago, that human intelligence capacity heredity is passed down thru the X chromosome. Since women have one each X from mother and father, their intelligence can be more average or diluted. By same token males get one X alone, so if he had a high-IQ mother it would stick in him, not affected by the father's Y.
Therefore, because the smartest females delay offspring if they have them at all, the collective gene pool is getting dumber now, devolution is here.
The remedy is for high-IQ females to delay college until menopause and have several kids, even if some have to be given up for adoptions (if she mates with a dumb unsupportive father). By the time he's retired she will be done with college and ready for a career while he's loafing around at home, maybe earlier when the kids ate teens. She and her prof'l career would support them all thence fore.

RS said...

> Maybe I'm oversimplifying, but if education, and not IQ, is 'determinative', then coming up with ways to keep people from spending 20+ years in school is likely going to have eugenic consequences.

Oh right, I see your point -- I agree, in that light it certainly does matter whether education is the proximal cause. --I was thinking in a 'static' or descriptive or predictive mode just then, rather than an interventional or prescriptive one.

To comment on the entire matter of dysgenesis, I've been very interested in it indeed, but it does seem like quite a vexed question. It's frustrating that you can't measure C very precisely (that I know of), it's trying to grapple with the Flynn effect (is it 'real' at all, does it involve the whole population or not, does it load on /g/ or not) -- and so on. A further difficulty or contradiction is that Blacks and Whites aren't necessarily diverging further in IQ, even though dysgenic fertility differentials appear quite a bit worse among Blacks.

However, the Flynn effect seems exhausted in advanced countries starting with c. 1980 births, the same time as the secular changes in height stop. Let's just say that this fact looks quite worrying, even given that we may be, in a variety of ways, less than wholly confident about various aspects of dysgenesis and the Flynn effect.

JayMan said...

I've done a follow up on this topic, and more. I've found that education does greatly reduce female fertility, but it is liberals who are impacted most, by far. See here:

Liberalism, HBD, Population, and Solutions for the Future | JayMan's Blog

Anonymous said...

Anonymous 5/30/12 9:32 wrote:

"I recall reading in the NY Times 15-20 years ago, that human intelligence capacity heredity is passed down thru the X chromosome."

What evidence is there that human intelligence is passed down through the X-chromosome?

Anonymous said...

Audacious, the article didn't claim actual intelligence, but the capacity level is passed down from the X.
The theory explained why females tend to have a more uniform and average IQ/intelligence level (with exceptions of course) -- while males have a broader spectrum of IQ levels. Males range from genius to retarded much more often than females. The theory that females' IQs are averaged from 2 XXs explains this; and males' undiluted X explains their wider IQ scale.
You'll have to search Google or NYT news history.

Anonymous said...

I found the NY Times article: http://www.nytimes.com/1997/06/12/us/parental-origin-of-chromosome-may-determine-social-graces-scientists-say.html

Also another later one:
http://www.nytimes.com/1998/05/14/us/first-gene-to-be-linked-with-high-intelligence-is-reported-found.html?pagewanted=all&src=pm

Anonymous said...

The second article just indicates an association of a certain mutation in one gene on the X-chromosome, IGF2, with increaed IQ, but it's a small effect if it's even been confirmed since the NYT article was written. Plomin himself is quoted in the piece saying that he expected more such genes to be found on all of the chromosomes. Neither article proves that intelligence is primarily passed down through the X-chromosome.

Brett Stevens said...

Education itself must be measured as a collection of components.

For example, education means more exposure to liberalism and urban lifestyles; it also means more focus on a career as opposed to a job; it also means more socialization.

Any of those also explain this problem.

However, I agree in general that what we call "education" has become an enemy of all that is good.

I would also point to one more factor: smarter people with more options tend to withdraw more from the world, as they're the ones who can tell it's in a suicide pattern.