The Bell Curve revisited

by philg

Driving back and forth to Nashua, NH yesterday I listened to The Bell Curve as an abridged book on tape (picked it up for $5 in a used bookstore in San Diego).  This book created quite a stir in 1994 because of its discussion of average IQ differences among races but I had never read it.  It turns out that even if you leave out all the controversial stuff about race the book is potentially very relevant to our times.


The Bell Curve starts out by talking about how we live in an era where people get sorted by cognitive ability into socioeconomic classes.  In 14th century England if you were a peasant with a high IQ or a noble with a low IQ it didn’t affect your life, reproductive potential, or income very much.  In our more meritocratic and vastly more sophisticated economy a smart kid from a lower middle class might make it to the top of a big company (cf. Jack Welch, who paid himself $680 million as CEO of GE) or at least into a $300,000/year job as a radiologist.  For the authors of the Bell Curve the increasing disparity in income in the U.S. is primarly due to the fact that employees with high IQs are worth a lot more than employees with low IQs.  They note that we have an incredibly complex legal system and criminal justice system.  So you’d expect people with poor cognitive ability to fail to figure out what is a crime, which crimes are actually likely to be punished, etc., and end up in jail.  (A Google search brought up a report on juvenile justice in North Carolina; the average offender had an IQ of 79.)  If they stay out of jail through dumb (literally) luck, there is no way that they are ever going to be able to start a small business; the legal and administrative hoops through which one must jump in order to employ even one other person are impenetrable obstacles to those with below-average intelligence.


The trend that the decade-old Bell Curve book misses is telecom and outsourcing.  The authors assume that an American with high IQ will have a higher income and better standard of living than an American with low IQ.  That’s the sorting function of an advanced economy.  They don’t get into the question of whether it is sustainable that an American with low IQ should have a higher income than someone in India or China with a high IQ.  Statistically, due to their sheer hugeness, you’d have to expect that there are more really smart people in India and China than the total population of the U.S.  If the sorting-by-IQ process were efficient across international borders you’d expect that an American with an IQ of 100 should be making less than an Indian with an IQ of 120.  Given that a lot of brilliant well-educated people in India are getting paid less than $5,000 per year, this is a bit worrisome those of us here who are fat, dumb, and happy.  [Imagine that you were running a company.  Would you rather employ a local high school graduate with an IQ of 90 or an Indian college grad with an IQ of 130 via Internet link?]


For us oldsters, one unexpected piece of cheerful news from this book is that younger Americans are getting genetically dumber every year.  Even if you ignore the racial and immigrant angles of the book that created so much controversy back in 1994 it is hard to argue with the authors’ assertion that smart women tend to choose higher education and careers rather than cranking out lots of babies.  As a middle-aged (40) guy whose own cognitive abilities are beginning to fade due to neuron death I felt sure that there would be no place me for in the America of 2050.  Our population is predicted to reach 450 million or so, i.e., the same as India had back when we were kids and our mothers told us about this starving and overpopulated country.  An individual person’s labor in India has negligible economic value–the American firm Office Tiger gets 1500 applicants, many of whom are very well qualified, on a good day in Chennai.  It would seem that no enterprise would need an old guy’s skills in a country of 450 million; why bother when there are so many energetic young people around?  And how would we be able to afford a house or apartment if there are 450 million smart young people out there earning big bucks and putting pressure on real estate prices?  But if the book is right most of those young people will be dumb as bricks.


[Update:  The Sunday New York Times has a long article in the Business section “Hourly Pay in U.S. Not Keeping Pace With Price Rises” about how American workers in jobs that don’t require high IQs are losing ground compared to the middle class and compared to inflation.  Raw labor isn’t worth very much right now.]

20 thoughts on “The Bell Curve revisited”

  2. I always felt the Bell Curve was a great and important book, overshadowed by the chapter on race (which is, as you note, irrelevant to the main argument), and by the authors known racial prejudices. I’m glad to see it noted again.

    You note “Statistically you’d have to expect that there are more really smart people in India and China than the total population of the U.S.”. The authors do investigate this point a bit in the book, and others have elsewhere. The first assumption underlying this is that all nations have similar intelligence distributions. There is evidence that this is not the case. The second assumption is that nations are isolated breeding populations. For China and India this is true, but for the U.S. it isn’t; smart people from all over the world (including China and India) come to the U.S. to be educated, then stay to have families here. So there is an ongoing upward tug on U.S. intelligence which is balanced by a corresponding downward tug in other countries.

    Great post.

  3. The New Yorker article is very good. Too bad that MIT is probably just as much a part of propogating the “Talent Myth” as McKinsey. I think you could probably rewrite the entire article using Ars Digita instead of Enron.

  6. Stephen: My IQ was tested when I was a student in Montgomery County Public Schools (back in the Jurassic Period) and I always scored the maximum (160?). Those tests, however, weren’t especially good at discriminating among people at the top end of the scale. I’ve never taken the newer really hard IQ tests that give folks such as Marilyn Vos Savant measured IQs over 200. Those tests can take many days or weeks and I was never interested in joining a high IQ club so I never bothered.

    PatW: IQ is reasonably well correlated with the ability to do white-collar work and is reasonably heritable (the New York article cited shows a correlation of nearly 0.3, about the same as SAT correlation with college grades). Given that a lot of people get above-average wealth through work and the remainder get it through inheritance from their parents it is hard to believe that there is no correlation with wealth. Furthermore with a U.S. prison population of 2 million and those folks having an average IQ of 80 and being out of the labor force altogether it would seem that you’d have to have higher wealth among those with higher IQs, if only because they are not in prison and therefore able to get a paycheck.

    New York article fans: It may be true that hiring a bunch of folks with an IQ of 140 isn’t a guarantee of profitability. It may also be true that in a large bureaucratic organization it might not be wise to let the really bright people have too much freedom. Imagine, however, that you needed some heart surgery done. Would you be happy to let yourself be opened up and worked on by doctors who had an average IQ of 100? Or would you prefer some docs with an average IQ of 130?

    Owen: ArsDigita might have made an okay example for the article. When I was running the company people were hired based on their performance solving some example problems (lifted from a class at MIT), not based on their IQ or educational credentials. People were rewarded based on how happy their customer was and how profitable their project was (P&L responsibility pushed down onto programmer teams). The company made millions of dollars in profits and put cash in the bank despite financing very rapid growth internally. After I departed in 2000 the same people with the same IQs managed to lose a lot of money because of some changes in management, notably the removal of P&L responsibility from customer-facing teams. On balance, however, New Yorker readers would not have wanted to see ArsDigita used as an example. Many of the employees of ArsDigita were computer programmers and nobody wants to read about people like that.

  7. Phil – This analysis is absolutely superb -tribute to your genius that you could associate two trends and write about your inferences in a brief manner. The advantage of more capable people available for enagements at lower costs coupled with telcom advancements is indeed an unbeatable combination.

  8. Phil – This analysis is absolutely superb -tribute to your genius that you could associate two trends and write about your inferences in a brief manner. The advantage of more capable people available for enagements at lower costs coupled with telcom advancements is indeed an unbeatable combination.
    sadagopan.

  9. It may also be true that in a large bureaucratic organization it might not be wise to let the really bright people have too much freedom.

    Isn’t MIT a large, bureaucratic organization?

    Would you be happy to let yourself be opened up and worked on by doctors who had an average IQ of 100?

    The best predictor for a successful surgery is how experienced the surgeon is at that type of surgery (http://www.wate.com/Global/story.asp?S=1488616).

  10. Sean: MIT research, except at the Media Lab, is conducted by individual labs that function as profit-and-loss units. A professor gets a grant, the money goes into an account, and as long as he or she pays a percentage of overhead the money can be spent as the professor sees fit. This is how nearly every research university operates. They are much more like a collection of individually-owned McDonald’s restaurants than like General Electric.

    The only portion of a typical research university that functions like a large bureaucracy is the administration. These are the folks who get the new buildings constructed, get the old buildings cleaned, coordinate the admissions, bill-collecting, bill-paying, registration, and transcript processes, etc.

  11. Oh yes, Sean, let me know when you find an experienced surgeon with an IQ of 100 who made it through the MCATs, medical school, internship, residency, and the Boards…

  13. Sean: Thanks for that last article. I love this guy Dr. Arndt! Reading New Yorker magazine, going to the gym to get buff, having sex with 15-year-old boys, making piles of money. He could have been a Roman emperor.

    I also like the fact that Arndt identifies with Dr. Jeffrey MacDonald, the Army physician who was convicted of murder and is currently represented by our friend and neighbor Harvey Silverglate (see http://www.silverglategood.com/cases/macdonald/).

    [A useful bit was “the 2002 median salary for spine surgeons was more than $545,000, according to the Medical Group Management Association”. I’ve been telling my students to go into radiology (average salary around $300,0000) but this might be better.]

  15. I badly worded my introduction to the NYT article. (A sign of my average IQ, perhaps?) Yes, higher IQ does equal better opportunities to earn more, but greater income doesn’t equate to more sex or sex partners, as legions of techies can attest. 🙂

  16. In his book, Emotional Intelligence, Psychologist Daniel Goleman makes a convincing case (convincing to me, anyway) that IQ is highly over-rated as a predictor of success in life. Goleman argues that other factors — such as the ability to get along well with others, to delay gratification, and to recover quickly from set-backs — are far more important than IQ. I think the book is worth reading.

  18. One of the unexplored miseries of modern life is the connection between poverty, whole language teaching in inner cities, and the rate of illiteracy among the incarcerated.

    Not all–not even the majority–of high IQ (140+) are early self-taught readers. There’s a certain overlap of ability and dyslexia–so the bright kid needs to be explicitly taught the sound-symbol association. Whole language just assumes, la la la, expose a child to good writing and the child WILL learn to read. Not.

  19. A fascinating book I read recently on the relationship between schooling, IQ, social background, race and economic success is a collection of essays edited by Kenneth Arrow: Meritocracy and Economic Inequality. Some of the essays are a bit technical, but the gist of them can be followed without a background in econometrics.

  20. If IQ is determined primarily by genetic inheritance, then it should ultimately be measurable at birth or early childhood. If IQ is a primary determinant for success later in life, then there should be profitable to offer scholarships to poor, but high IQ children, in exchange for a percentage of their future earnings. It’s too bad that such arrangements are probably not legal.

    However, K.A. Ericsson’s research suggests that practice is a bigger determinant of expertise than native IQ:

    “… When experts exhibit their superior performance in public their behavior looks so effortless and natural that we are tempted to attribute it to special talents.

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