I Introduction
The Bell Curve: Intelligence and Class Structure in American Life, published in 1994 by
Richard Herrnstein (now deceased) and Charles Murray, has been one of the most controversial
books of the past several decades. It discusses the variations in intelligence in the United States,
illustrates possible causal effects of this intelligence gap on social behavior, and proposes
national social policies that acknowledge the existence of an intelligence gap and its impact on
American society. Many of the assertions and conclusions are extremely controversial, ranging
from the claim that low measured intelligence strongly predicts socially undesirable behavior to
the proposition that a genetic factor in cognitive ability is the main reason behind the low IQ test
scores of African-Americans (compared to the scores of whites and Asians).
The book received much public attention and became a bestseller soon after it was
released. In the first several months of its release, 400,000 copies of the book were sold around
the world. Thousands of reviews and commentaries, from both the general public and academia,
were written in the wake of the book's publication. Reactions came from economists, sociologists,
psychologists, mathematicians, politicians and the press, generating a huge debate over the link
between human intelligence and social behaviors. A wide range of topics and issues in social
sciences were discussed in the debate, including the psychological concept of intelligence, the
validity of IQ and other instruments testing mental ability, the origin of within- and between-
group differences in cognitive ability, the relative predictive power of genetic mental aptitudes
versus socio-economic status in predicting social success/failure, and the effectiveness of
educational training programs, especially those developed to improve intelligence.
This paper focuses on one specific issue: the effect of intelligence on within- and
between-group wage rate differences. The Bell Curve asserts that cognitive ability is the most