Has The Bell Curve been completely discredited?

[dalej42]

Several years ago, the controversial book The Bell Curve was published. The book discusses racial differences in IQ levels. There was a howl of criticism and allegations of racism. As I now pick up the book for the first time in years, I"m wondering what cognitive psychologists now say about the basic premise of The Bell Curve?

Should we attempt to measure differences in IQ level between races?

Are there such differences?

How might these differences have contributed to the situation in New Orleans?

I’m certainly not a psychologist and I remember this book was a fairly difficult read. Thankfully, my understanding of statistics is far greater than it was when I first read the book in college.

Anyone care to point to one of the many counterbooks which challenges The Bell Curve?

[Knorf]

One point of order: there is one human race, Homo sapiens. To speak of “races” regarding humanity–on a genetic level at least–is in most senses a misnomer. Race has meaning on some cultural, social, and superficial appearance levels, which admittedly are non-trivial, but when it comes to genetics, the word race has very little meaning at all.

My sense is that “The Bell Curve” has indeed been largely and effectively discredited, but I’m sure other Dopers have the facts more readily available to them about that then I presently do.

Simply put, I cannot draw conclusions from anything other than cultural and social sources regarding the lapse of civil order and inept response from the Federal Government regarding the present catastrophe in New Orleans.

[Shagnasty]

I’ll put myself in the fire a little.

I read The Bell Curve for an Intelligence class when I was in graduate school at Dartmouth. We discussed the book and critisized it at length. While the book does have many theoretical and statistical flaws, the basic premise is real and shows up everywhere we measure in this country. Given an adequate sample size, whites almost always outscore blacks on any test designed to measure IQ or academic achievement. This effect shows up on traditional IQ tests, the SAT, the ACT, and high school graduation tests and others. It is present at every age as well. To the best of my knowledge, no one has ever designed a test measuring academic aptitude where blacks score higher than whites. This effect even shows up past the undergraduate level and into tests for graduate and professional school admissions. That is why there was such an uproar over ending affirmative action at schools like the University of Texas. Few black students could score well enough on tests to compete for slots in the Law School and others without AA.

Based on that data, I would say it is not completely discredited. OTOH, the effect doesn’t have to be genetic. It could be because of differences in parenting styles in early learning for example. There could be lots of reasons why we see this.

Much of the critisism of the book focuses on the fact that African Americans are extremely genetically diverse and are not that closely related to one another. That is correct but the effect still remains.

[Kimstu]

As far as I know, there has been no convincing rebuttal of the major criticisms of The Bell Curve made when it was first published. Cf. Stephen Jay Gould’s 1994 review, “Curveball”:

“The Bell Curve,” with its claims and supposed documentation that race and class differences are largely caused by genetic factors and are therefore essentially immutable, contains no new arguments and presents no compelling data to support its anachronistic social Darwinism […]

“The Bell Curve” rests on two distinctly different but sequential arguments, which together encompass the classic corpus of biological determinism as a social philosophy. The first argument rehashes the tenets of social Darwinism as it was originally constituted. “Social Darwinism” has often been used as a general term for any evolutionary argument about the biological basis of human differences, but the initial nineteenth-century meaning referred to a specific theory of class stratification within industrial societies, and particularly to the idea that there was a permanently poor underclass consisting of genetically inferior people who had precipitated down into their inevitable fate. […]

The general claim is neither uninteresting nor illogical, but it does require the validity of four shaky premises, all asserted (but hardly discussed or defended) by Herrnstein and Murray. Intelligence, in their formulation, must be depictable as a single number, capable of ranking people in linear order, genetically based, and effectively immutable. If any of these premises
are false, their entire argument collapses. […]

Herrnstein and Murray’s second claim, the lightning rod for most commentary, extends the argument for innate cognitive stratification to a claim that racial differences in I.Q. are mostly determined by genetic causes – small differences for Asian superiority over Caucasian, but large for Caucasians over people of African descent. This argument is as old as the study of race, and is almost surely fallacious. […] The central fallacy in using the substantial heritability of within-group I.Q. (among whites, for example) as an explanation of average differences between groups (whites versus blacks, for example) is now well known and acknowledged by all, including Herrnstein and Murray […]

Disturbing as I find the anachronism of “The Bell Curve,” I am even more distressed by its pervasive disingenuousness. The authors omit facts, misuse statistical methods, and seem unwilling to admit the consequences of their own words. […]

Virtually all the analysis rests on a single technique applied to a single set of data – probably done in one computer run. (I do agree that the authors have used the most appropriate technique and the best source of information. Still, claims as broad as those advanced in “The Bell Curve” simply cannot be properly defended – that is, either supported or denied – by such a restricted approach.) […]

Nothing in “The Bell Curve” angered me more than the authors’ failure to supply any justification for their central claim, the sine qua non of their entire argument: that the number known as g, the celebrated “general factor” of intelligence, first identified by the British psychologist Charles Spearman, in 1904, captures a real property in the head. […]

Herrnstein and Murray claim that they only want a hearing for unpopular views so that truth will out. And here, for once, I agree entirely. As a card-carrying First Amendment (near) absolutist, I applaud the publication of unpopular views that some people consider dangerous. I am delighted that “The Bell Curve” was written – so that its errors could be exposed, for Herrnstein and Murray are right to point out the difference between public and private agendas on race, and we must struggle to make an impact on the private agendas as well. But “The Bell Curve” is scarcely an academic treatise in social theory and population genetics. It is a manifesto of conservative ideology; the book’s inadequate and biased treatment of data displays its primary purpose – advocacy.

A more technical discussion can be found in a Skeptic.com review of Fischer et al., Inequality by Design—Cracking the Bell Curve Myth.

As for the specific questions in your OP:

Should we attempt to measure differences in IQ level between races?

Fine by me, if you can come up with a biologically rational means of distinguishing between “races”, and a psychologically or cognitively meaningful and consistent interpretation of “IQ level”.

Are there such differences?

AFAIK, nobody knows, because of the abovementioned difficulties in meaningful identification and measurement.

How might these differences have contributed to the situation in New Orleans?

Well, if blacks are intrinsically stupider than whites, then presumably the mostly-black population trapped in the flooded city handled the situation more stupidly than a comparable group of whites would have. Is that the answer you were looking for?

As the above links and comments indicate, however, there is no scientifically supported reason to think that blacks are in fact intrinsically stupider than whites. In fact, there is so little scientific support for that hypothesis that no rational person is likely to accept it, unless it’s what they want to believe.

[Contrapuntal]

@Kimstu

Well, if blacks are intrinsically stupider than whites, then presumably the mostly-black population trapped in the flooded city handled the situation more stupidly than a comparable group of whites would have. Is that the answer you were looking for?

Admirable restraint, Kimstu.

[Kimstu]

@Shagnasty

To the best of my knowledge, no one has ever designed a test measuring academic aptitude where blacks score higher than whites. […]

Based on that data, I would say it is not completely discredited. OTOH, the effect doesn’t have to be genetic.

But the central thesis of The Bell Curve is its attempt to show scientifically that “race and class differences are largely caused by genetic factors”. So if “the effect [of those differences] doesn’t have to be genetic”, then the book is pretty much completely discredited.

What is not discredited, and what is in fact universally accepted, is the simple observation that you mention, namely that American blacks on average tend to score lower on academic aptitude tests than American whites. But everybody already knew that before Herrnstein and Murray wrote their book.

We still don’t know for certain why that difference exists; it’s not a priori impossible that some genetic factor could be involved. However, The Bell Curve completely failed in its attempt to demonstrate scientifically that it is.
[And thanks, Contrapuntal, I’ve had lots of practice. ;)]

[Aagramn]

This article does a good job of discrediting The Bell Curve.

http://www.bostonreview.net/BR20.6/block.html

It points out that measured IQs have been steadily rising in the many countries over the last few decades.

For example, average IQ in Holland rose 21 points between 1952 and 1982

Pretty good evidence that the environment you grow up in has a large bearing on your IQ.

[Shagnasty]

I guess this is as good a place as any to ask this.

Do black students in Europe generally score lower on intelligence, aptitude, and achievement test than their white counterparts?

[Kimstu]

According to the Gould review I linked to above,

This case includes such evidence as impressive I.Q. scores for poor black children adopted into affluent and intellectual homes; average I.Q. increases in some nations since the Second World War equal to the entire fifteen-point difference now separating blacks and whites in America; and failure to find any cognitive differences between two cohorts of children born out of wedlock to German women, reared in Germany as Germans, but fathered by black and white American soldiers.

That suggests (well, actually, it categorically states) that for “GI babies” reared in German families, there was no detectable difference in intelligence caused by having a white vs. black father.

As far as I know, there are systemic differences in academic achievement in European populations between children of “ethnically native” people and children of immigrant groups. But, again AFAIK, the low-scoring groups include not just “blacks” of African descent but also West Asian “Semitic” peoples as well as ethnically Caucasian Turks and Kurds.

[John_Mace]

You have to remember, though, that the fundamental premise of the book was not about race. They could have written the entire book about a racially homogenous society. There were, IIRC, only 2 chapters that dealt explictly with the racial aspects of the thesis.

They postulated that because of the heritability of intelligence, and the increasing importance of that trait in a highly technical society like ours, that we’d see the emergence of an “intelligence elite” that would be more or less self perpetuating. It was almost a restating of Social Darwinism, although not in any sense meant to be a justification for giving up on the downtrodden. It’s been quite awhile since I read the book, but I thought they were making the case that society needed to take some proative steps to ensure that we didn’t develop MORE into a stratified society. And, since there is a “bell curve”, there is no reason that many Blacks would not themselves become part of the “intelligent elite”-- ie, even though Blacks as a group score lower on IQ tests than Whites, there are still plenty of individual Blacks who will score higher than most Whites.

[Kimstu]

@John Mace

There were, IIRC, only 2 chapters that dealt explictly with the racial aspects of the thesis.

However, a lot of the rest of the book also discussed racial themes and race-based data. (There’s really no way to avoid that if you’re trying to talk about heritability and social class in America, after all. About the only genetically-based class factor we have significant data about is race.)

Moreover, Herrnstein and Murray themselves emphasized the significance of race in their discussion, as Gould pointed out:

THE ocean of publicity that has engulfed “The Bell Curve” has a basis in what Murray and Herrnstein, in an article in The New Republic last month, call “the flashpoint of intelligence as a public topic: the question of genetic differences between the races.” And yet, since the day of the book’s publication, Murray (Herrnstein died a month before the book appeared) has been temporizing, and denying that race is an important subject in the book at all; he blames the press for unfairly fanning these particular flames. In The New Republic he and Herrnstein wrote, “Here is what we hope will be our contribution to the discussion. We put it in italics; if we could, we would put it in neon lights: The answer doesn’t much matter.”

Fair enough, in the narrow sense that any individual may be a rarely brilliant member of an averagely dumb group (and therefore not subject to judgment by the group mean), but Murray cannot deny that “The Bell Curve” treats race as one of two major topics, with each given about equal space; nor can he pretend that strongly stated claims about group differences have no political impact in a society obsessed with the meanings and consequences of ethnicity. The very first sentence of “The Bell Curve” 's preface acknowledges that the book treats the two subjects equally: “This book is about differences in intellectual capacity among people and groups and what those differences mean for America’s future.”

If they’re going to use race-related data as (allegedly) a key support for their arguments, and state alleged findings about race-based differences in intelligence, they can’t turn around and protest that the racial aspect of the debate is unimportant.

Yes, it would be possible to make the same claim about heritable class stratification in a racially homogenous society too. But if you make such a claim in a racially inhomogeneous society, where the only significant heritable characteristic you’re studying is race, then it’s disingenuous to pretend that race is actually irrelevant to what you’re saying.

[John_Mace]

@Kimstu

Yes, it would be possible to make the same claim about heritable class stratification in a racially homogenous society too. But if you make such a claim in a racially inhomogeneous society, where the only significant heritable characteristic you’re studying is race, then it’s disingenuous to pretend that race is actually irrelevant to what you’re saying.

No one said race was “irrelavent” in the book. And the fact that the authors DID include 2 full chapters expicitly about race is an indiaction that it does have at least some level of importance. But it’s still true that the central thesis of the book is **not **about race. I could just as well right a book about the state of the legal system in the US, include a few chapters about race, and my book would not be a book about “Race and the law in the USA”.

Frankly, I think their central thesis is bunk. Sure, intelligence is heritible. It has to be-- otherwise all living species of animals would be of equal intelligence. But we know very little about how to measure that quantity and how mating patters are affected by it. We’re a loooooong way from living in a society where the social sciences have attained the level of sophistication in Asimov’s *Foundation *trilogy.

[jshore]

John:

I must admit that I never read the book but from what I heard about its political philosophy and those of its authors, I have a hard time believing that “they were making the case that society needed to take some proative steps to ensure that we didn’t develop MORE into a stratified society.”

In fact, I thought they were in large part arguing against things like affirmative action…i.e., making the argument that such an approach was bound to fail because the differences in achievement were based not on environmental factors, racism, etc. but rather on innate differences (sort of similar to the sort of statements that Lawrence Summers made in regards to women faculty a year or so ago).

[Honesty]

@dalej42

Should we attempt to measure differences in IQ level between races?

Well, as a 23 year old gay black man, I’ll give you my opinion: NO!

That book has been a demon that, at times, has completely sapped my will to move forward. “Oh god! I got a C on this test,” I would say to myself. “I studied so much, it has to be because I am just less intelligent than everyone else.” Can any of you understand the significance of that? Can you envision a popular and widely-read book that presents itself under the narrow microscope of scientific inquiry conclude that the group you belong to are less intelligent than everyone else? If you succeed and graduate from college, you’re marred with the Affirmative Action brush; If you fail or drop out, then its OK, because everyone knows you’re stupid and that Affirmative Action program don’t work anyway. It’s damned if you do, damned if you don’t.

I’ve been a member of the Straightdope community for over five years and I don’t even think I’ve posted over 200 times. Why? Because I’m afraid that I’ll slip up and make a mistake. I don’t want anyone to say to themselves, “Oh wow! Look at him! They sure are dumb!” It’s a blessing and a curse. On one hand, I am driven forward to succeed; on the other, I am less apt to state my opinion in fear that it may be considered dumb or stupid.

I’ve read *The Bell Curve * and Mismeasure of Man but I, much to my disappointment, remain largely inconclusive. I do have a question for those who do believe that there are cognitive differences between “racial” groups:

If black students must come overcome the genetic mires of an inherently low IQ, should black students be measured by the same measuring stick as whites? That is, If there is a black student who gets a C- in a class filled with 1000 white students what grade should he get?

• Honesty

[tomndebb]

Can you envision a popular and widely-read book that presents itself under the narrow microscope of scientific inquiry conclude that the group you belong to are less intelligent than everyone else?

You do realize, I hope, that however popular its perceived message may have been in some circles, it was never a “widely-read” book? Regardless how many copies it may have sold, very few of the people who defend (or attack) it have ever read it.

[John_Mace]

@jshore

John:

I must admit that I never read the book but from what I heard about its political philosophy and those of its authors, I have a hard time believing that “they were making the case that society needed to take some proative steps to ensure that we didn’t develop MORE into a stratified society.”

In fact, I thought they were in large part arguing against things like affirmative action…i.e., making the argument that such an approach was bound to fail because the differences in achievement were based not on environmental factors, racism, etc. but rather on innate differences (sort of similar to the sort of statements that Lawrence Summers made in regards to women faculty a year or so ago).

Perhaps you should read the book, then, instead of relying on your preconceived ideas of what the authors advocate. Affirmative Action, in the guise of racial quotas or giving special preference to certain racial groups, is not the only way to address racial inequities proactively.

Keep in mind that I don’t buy the authors’ thesis, so I don’t buy into their remedies either. But the book is about the heritability of intelligence and how a knowledge-based economy will change from a stratification based on social class to one based on intelligence. The thesis has important implications for race relatiions in a country like the US, but it is NOT a book about race.

[II_Gyan_II]

It just so happens that Charles Murray has a long reiterating précis this month in Commentary. We can work with that.

[John_Mace]

@Honesty

If black students must come overcome the genetic mires of an inherently low IQ, should black students be measured by the same measuring stick as whites? That is, If there is a black student who gets a C- in a class filled with 1000 white students what grade should he get?

Let’s assume for a moment that the conclusions in this book are true. Those conclusions say nothing, NOTHING, about individuals. If you want to know how “intelligent” you are, take an IQ test and see where you fit on the bell curve.

In the hypothetical class you mention, there will be a random distribution of intelligence among the White students. Even if the conclusions of The Bell Curve are correct, there will almost certainly be many White students in that class who are less intelligent (ie, have a lower IQ) than the Black student, and the rest of the class. What grade should those White students get?

[Sarah_Woodruff]

This is all assuming that I.Q. tests can be proven to be free of cultural bias with regard to nonwhites, anyway. Has this been proven?

[zagloba]

Honesty, your reaction, and it’s mirror image where non-blacks prejudge blacks as ipso facto intellectually inferior are precisely why such books are so dangerous. They lead people to forget to treat people as individuals. Even if it were true that blacks on average were less intelligent than non-blacks, that doesn’t determine anything about you or any other individual. Even then, looking at a person’s skin wouldn’t tell you how intelligent they were. I understand how you could get thoughts like those you expressed in your post, but it makes me sick that we live in a society that gives you reason to have them.

OK, I guess that doesn’t contribute to the debate, but you’re post really struck me for some reason.