The Bell Curve: Intelligence and Class Structure in American Life -R. Herrnstein & C. Murray, Free Press, New York, 1994.	
This book was written by a psychometrician (Herrnstein) and a political scientist (Murray) to “objectively” present the  scientific data “proving” that not only do low IQ scorers have a rotten time in their life but furthermore IQ can be equated to race (or ethnicity if you swallow their sincerity in being  political correct). If follows in the (in)famous tradition of Arthur Jensen (Berkeley), Hans Eysenck (London) and even more recently Chris Brand (Edinburgh), who come under the label of “scientific racists”, with a resulting furore in both the US and the UK. The authors present data to show that Asians are marginally more intelligent than Caucasians but scoring at an average at one standard deviation below the Caucasians are the African-American race.
Let me start this review with one positive note and that is that they have a pretty neat appendix describing statistics for non-statisticians. However, I doubt that this is a good enough reason to buy the book (unless you’re a convert of the credo that race and IQ are virtually interchangeable, who would like to be preached to).
Dismissing Contrary Evidence
The authors do try to dismiss the strong claims of Herrnstein’s Harvard colleagues Stephen Jay Gould and Howard Gardner. Gould’s deservedly successful book, The Mismeasure of Man, I thought had successfully demonstrated that any “differences” between races are not so much to do with the true reflection of “intelligence” or ability, but rather the ability to take intelligence test. I cannot find any evidence in this book to suggest that Gould was incorrect in his thesis.
Howard Gardner is perhaps the modern doyen of the school that believes it is not productive to continue to talk about a single unitary concept of “intelligence”, and he too is dismissed as being short of the mark with respect to his theory of “Multiple Intelligences”. Herrnstein & Murray advocate that verbal and non-verbal logical thinking (read mathematics) are qualitatively the right stuff of intelligence (I still haven’t found the reason in their book why this should be so), whereas Gardner’s proposed alternative intelligences (such as musical ability, kinaesthetic ability, inter- & intra-personal relationships and artistic ability) should instead be deemed to be called “talents”. Gardner in turn has replied (the authors even provide this quote):
“If critics are willing to label language and logical thinking as talents as well, and to remove these from the pedestals that they currently occupy, then I would be happy to speak of multiple talents”.
Touché!
Meaning in Statistics
There is no doubt that Herrnstein & Murray have amassed a substantial amount of statistical evidence to prove their points but my own cynicism of the book starts with their book title. Many scientists believe that a bell shaped distribution curve for nature’s attributes (including biological intelligence) is “natural” and we can take as granted. However, there is no proof that this is indeed a natural “law” and is very much dependant on the measuring scales that are used to assess nature’s attributes. Of course one can (and many have) engaged in a lovely circular arguments that goes something like this:
(I)	Assume that intelligence follows a bell shaped distribution in the population. 
(II)	You hand out a huge number of questions that you believe relate to “intelligence”. 
(III)	Statistically analyse each question and retain those  that show a bell shape distribution in the answers, discard the rest. 
(IV)	Compile the retained questions and call it an “intelligence” test. 
(V)	Apply it to a population and fall over backwards in utter amazement as the scores appears to show a bell shaped distribution! 
My own belief is that much of Herrnstein & Murray's argument rests on the psychometric wisdom that intelligence is indeed bell shaped in its distribution, and if this is not the case then their argument will whither under scrutiny to a tiny nothing.
In principle, I have no quibble with the results that purport to show that African-Americans score on average 1 standard deviation below Caucasians. My quibble is the assertion that not only is intelligence testing an objective beyond-doubt-phenomena, but also in the interpretation of what this difference “means”. A high IQ score may indeed be a reasonable predictor of future scholastic success. Let the IQ test be used in this context, but let us not pretend that the IQ tests can tell us “why” a person obtains a particular IQ score. Herrnstein & Murray’s correlation of IQ with race they feel provides scientific proof that for some people the “cause” of low IQ is through no fault of anyone except the genetic (and therefore unalterable for an individual) contribution. 
The case for “scientific racism” has been previously made before and refuted as the authors acknowledge. If they were really trying to present an ‘objective’ and ‘scientific’ point of view then they should conclude that they provide no additional support to this thesis – but then maybe they are not completely ‘objective’ or even ‘scientific’ so they did not conclude this.
Their final chapters try to integrate their objective findings with present social dilemma’s and future trends unless corrective action is taken. Their solution essentially suggests that America can alleviate  the present day social ills, by a returning to “traditional” values of the United States in the 1950s. Did I hear someone say the “Cold War”, Joe McCarthy to say nothing of racial segregation?