Intelligence, Race, and Genetics

            This little book of about 200 pages consists mainly of passages from an extended interview conducted by e-mail with Arthur Jensen, the infamous psychologist.  Following a brief  “Prelude” that tells us a little about Jensen the man, are six chapters, each on a particular topic.  Five of these chapters focus on Jensen’s controversial contributions to the study of intelligence; one chapter, the last, concerns his views about public policy.  Each chapter begins with a summary of the conversation to follow and ends with a bibliography. The author’s frank and forthright questions are admirably intelligent, well informed, and clear—as are Jensen’s frank and forthright replies.  The book ends with a complete bibliography of Jensen’s prolific writings, a brief summary of what he and a group of his fellow psychometricians take to be the results of mainstream science on intelligence.  There is also an index. Anyone who wants a non-technical but lucid exposition of Jensen’s views about the relations between IQ, genes, and race will find it here.

Since the statements made in this book are already simplified—though never simplistic—summaries of highly complex issues, I will not try here to simplify them still further.  Since these statements have also been the subject of heated controversy in which I do not wish here to become embroiled, I will also not give you my opinions about them.   Instead, I will limit this review to listing the issues that are discussed.  Chapter 1, “Jensenism,” recounts the story of the dismayed and intemperate reaction to Jensen’s now infamous, 1969 essay in the Harvard Educational Review declaring that, since much of the 15 point IQ gap between blacks and whites is due to genetic differences, only a small part of it can be eradicated by education.  The chapter also contains Jensen’s assurance that his motives in saying so were not political.  Chapter 2, “What is Intelligence,” contains a discussion of intelligence and the success of IQ tests in measuring it.  Here, Jensen gives us his reasons for believing that Carl Pearson’s famous g—for general intelligence—is real and important.  Chapter 3, “Nature, Nurture, or Both” contains the clearest and simplest discussion of the concept of heritability that I have ever seen.  It also offers a summary of the evidence —gleaned mostly from comparing twins reared apart and unrelated persons reared together—for the proposition that the heritability of g is somewhere around .70.  Chapter 4, “What is Race” gives Jensen’s reasons for believing, despite recent claims to the contrary, that races are real and distinguished by gene frequencies that affect behavior as well as physique. Jensen’s reply to Cavali-Sforza is that the latter’s talk of “population groups” is just alternative vocabulary for “races.”  Chapter 5, “From Jensenism to the Bell Curve Wars,” recounts Jensen’s remarkably restrained responses to the frequent charge that his work consists of politically motivated pseudo-science.   He says that he will be glad to reply to criticisms published in refereed journals but will not answer ad hominem attacks.  Although Jensen says that his main interest has always been science, not politics, Chapter 6 “Science and Policy” asks him to give his opinions on political questions.  He replies that he believes in equal opportunity and thinks that the schools should tailor educational programs to suit the needs and interests of individual students. 

            It is a nicely done book about the important work of an impressive scientist on an incendiary topic.   I recommend it.

© 2002 Max Hocutt

Max Hocutt, Ph.D., Professor of Philosophy Emeritus, The University of Alabama