In 1969, Arthur Jensen published his controversial article concluding that blacks are less intelligent than whites and that genetic factors explain more of the variance between the two groups than environmental differences. This paper criticizes Jensen's work and discusses its negative implications. Interpretive and methodological weaknesses in Jensen's research are described, including erroneous assumptions regarding environmental effects and gaps and incomplete analysis of variance in Jensen's data. The validity of IQ scores is then examined. It is held that IQ is a culturally biased measurement, subject to environmental influences, and that, furthermore, Jensen's interpretation of IQ scores is different for blacks and disadvantaged children than for whites. Next, political and social misuses of the Jensen hypothesis are discussed. Principal effects of Jensen's work are said to be enhancement of feelings of racial superiority among whites, reinforcement of the myth of individual responsibility for social mobility, the evolution of the "culture of poverty" thesis, and support for the status quo in the American educational system. Finally, Jensen's work is said to exemplify how a scholar's values, as well as his own background, may lead him to be less objective than he thinks, especially in regard to subjects dealing with race, heredity, and environment. (Author/GC)