Heritability and educational policy: Genetic and environmental effects on IQ, aptitude and achievement

Abstract

Some common beliefs about the fairness of achievement tests, in comparison with IQ tests, and about the role of genetic differences among individuals and social‐class groups in determining academic achievement are challenged by a study investigating the effects of family background on adolescents’ IQ, aptitude, and school achievement tests scores. The study included 115 adoptive families with adolescent children, adopted in the first few months of life, and a comparison sample of 120 biological families with their own adolescent offspring. Both sample of families ranged from solid working to upper‐middle class. Results of the study revealed that differences among social‐class environments have little effect on IQ scores but larger effects on school‐achievement scores. Contrary to the beliefs of many school personnel, working‐class adolescents are at a greater disadvantage relative to upper‐middle‐class adolescents when the tests sample recently taught material. Genetic differences among individuals and am...