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The graph of the probability density function of the normal distribution is often called "the bell curve". See normal distribution for that topic.

The Bell Curve is a controversial book published in 1994 by R. J. Herrnstein and Charles Murray exploring the role of intelligence in understanding social problems in America. The title is a reference to the bell-shaped graph of IQ scores (see normal distribution).

The primary argument of the book concerns the emergence of a "cognitive elite", a social stratum of persons with both high wealth and high intelligence, and how it contributes to the isolation of socioeconomic and cognitive classes in the United States. Although only a small fraction of the book concerns the topic of race, its statements regarding race and intelligence are those that have stirred the most controversy, causing many to denounce the book and its authors.

"But the most explosive of The Bell Curve's arguments is that some of the difference in mean IQ scores between the white European population of the United States and the African-American population (one full standard deviation of 15 points) is probably attributable to genetic factors. No one in the field disputes this difference. The argument is over why the difference exists and, of course, whether and how it can be reduced." [1]

Following in the footsteps of Harvard researcher Arthur Jensen, Herrnstein and Murray include reams of statistical data showing a correlations between IQ and various social phenomena. The authors report that estimates from psychometricians of the heritability of intelligence range from 40% to 80%. They report that there exist significant correlations between intelligence and various ethnic categories. They argue that a better public understanding of the nature of intelligence and its social correlates is necessary to guide future policy decisions in America.

1 Responses

Thanks to a stunningly-successful PR campaign by the books institutional supporters, The Bell Curve, while weighing in at over 800 pages, received an incredible publicity including cover stories in Newsweek, The New Republic, and The New York Times Book Review. Early articles and editorials appeared in Time, The New York Times, The New York Times Magazine, Forbes, the Wall Street Journal, and The National Review. The book sold over 300,000 copies in hardcover. It was featured in the 1994 film With Honors to demonstrate a character's intellectual toughness.

Dr. Herrnstein died before the book was released, leaving Charles Murray to do most of the public defense of the book. Although Herrnstein was a prominent psychologist, Murray has a Ph.D. in political science but no formal credentials in economics or psychometrics, the two fields in which his books have sparked the most serious debate. None of his book's contents or conclusions were submitted to peer-reviewed journals.

Reviewing The Bell Curve in the peer-reviewed American Behavioral Scientist , professor Michael Nunley wrote "I believe this book is a fraud, that its authors must have known it was a fraud when they were writing it, and that Charles Murray must still know it's a fraud as he goes around defending it. ... After careful reading, I cannot believe its authors were not acutely aware of ... how they were distorting the material they did include."

Professor Leon J. Kamin said the book did "a disservice to and abuse of science." Craig T. Ramey, a professor of psychiatry and pediatrics at the University of Alabama said "Within the sophisticated research community, the opinion has been virtually unanimous that The Bell Curve was a primitive, oversimplistic and flawed analysis."

In an attempt to defend the book, 52 experts in the study of intelligence and related fields signed a notice, published in The Wall Street JournalThe Wall Street Journal is an influential international daily newspaper published in New York City, New York with an average daily circulation of 1,800,607 (2002). For many years, it had the widest circulation of any newspaper in the United States, althou, December 13December 13 is the 347th day of the year (348th in leap years) in the Gregorian calendar. There are 18 days remaining. Events 1545 Council of Trent begins 1577 Sir Francis Drake sets out from Plymouth, on his round-the-world voyage 1642 Abel Janszoon Tasm, 1994, in support of some of the conclusions in The Bell Curve.

A special American Psychological Association task force set up to review the book issued a report assessing the science behind it.

Another popular book written at least in part to refute some of The Bell Curve's claims is the Pulitzer Prize winning Guns, Germs, and Steel: The Fates of Human Societies, by Jared Diamond. Diamond argues that the differences in technology produced by various races are the result of differences in factors like terrain or the availability of natural resources -- not on differences in intelligence.

Bauer speaks in part to Diamond's thesis, saying:

"African backwardness amidst ample natural resources is only one conspicuous example of the fact that material progress depends on personal qualities, social institutions and mores, and political arrangements which make for endeavour and achievement, and not simply physical resources." P.T.BAUER, 1981, Equality, the Third World and Economic Delusion. London : Methuen.

But the most fundamental factor in technological development, according to Diamond, is a geographic location that allows easy exchange of technology with numerous and distant cultures. And according to Diamond, the regions of Africa that remained most technologically undeveloped were also the most isolated geographically.

A recent paper in the Psychological Review, "Heritability Estimates Versus Large Environmental Effects: The IQ Paradox Resolved" presents a mechanism by which environmental effects on IQ may be magnified by feedback effects. This may provide a resolution of the contradiction between the viewpoint of The Bell Curve and its supporters, and the 'nurture' factors of IQ believed to exist by its critics.