The entire thesis of "The Bell Curve" disintegrates due to biased use of data, misrepresentations, and logical inconsistencies. Five basic flaws are: inferring causality from correlation, use of dubious racial categories, contradictory arguments concerning the immutability of cognitive ability and the relative contributions of heredity…

"The Bell Curve" declares that studies of separated identical twins--the "purest" of "direct" methods for estimating IQ heritability--indicate a value of +.75-+.80. But, the main study cited suggests a heritability of "two-thirds" for the middle class, and Herrnstein and Murray neglect to mention numerous…

Argues that Herrnstein and Murray's cognitive stratification is not intrinsically ominous, since context determines its meaning; their "intelligence" data actually measures educational achievement; environmental effects are underestimated; and analyses and social policy recommendations are bound to the U.S. context. Concludes that…