The Bell Curve: Intelligence and Class Structure in American Life is a 1994 book by psychologist Richard J. Herrnstein and political scientist Charles Murray, in which the authors argue that human intelligence is substantially influenced by both inherited and environmental factors and that it is a better predictor of many personal outcomes, including financial income, job performance, birth out of wedlock, and involvement in crime than are an individual's parental socioeconomic status. They also argue that those with high intelligence, the "cognitive elite", are becoming separated from those of average and below-average intelligence, and that this separation is a source of social division within the United States. The book was and remains highly controversial, especially where the authors discussed purported connections between race and intelligence and suggested policy implications based on these purported connections. Shortly after its publication, many people rallied both in criticism and in defense of the book. A number of critical texts were written in response to it. Many criticisms were collected in the book The Bell Curve Debate. Synopsis The Bell Curve, published in 1994, was written by Richard Herrnstein and Charles Murray to explain the variations in intelligence in American society, warn of some consequences of that variation, and propose social policies for mitigating the worst of the consequences. The book's title comes from the bell-shaped normal distribution of intelligence quotient (IQ) scores in a population. Introduction The book starts with an introduction that appraises the history of the concept of intelligence from Francis Galton to modern times. Spearman's introduction of the general factor of intelligence and other early advances in research on intelligence are discussed along with a consideration of links between intelligence testing and racial politics. The 1960s are identified as the period in American history when social problems were increasingly attributed to forces outside the individual. This egalitarian ethos, Herrnstein and Murray argue, cannot accommodate biologically based individual differences. The introduction states six of the authors' assumptions, which they claim to be "beyond significant technical dispute": There is such a difference as a general factor of cognitive ability on which human beings differ. All standardized tests of academic aptitude or achievement measure this general factor to some degree, but IQ tests expressly designed for that purpose measure it most accurately. IQ scores match, to a first degree, whatever it is that people mean when they use the word intelligent, or smart in