ARE AMERICANS BECOMING MORE-OR-LESS ALIKE - TRENDS IN RACE, CLASS, AND ABILITY DIFFERENCES IN INTELLIGENCE

American students' test scores have been slowly but steadily declining for the past half century. Some recent explanations for this decline have focused on dysgenic trends resulting from low-IQ parents outbreed ing high-IQ parents. In this article, the authors examined the evidenc e for dysgenic trends by considering race-, class-, and ability-relate d changes in intelligence test scores over time. They concluded that ( a) racial differences in intelligence decreased from 1973 to 1988 and have remained fairly constant since, (b) intelligence differences betw een the upper and lower thirds of social class groups have been decrea sing slightly since 1932, and (c) Preliminary Scholastic Assessment Te st-score differences between the top and bottom quartiles have been re latively stable since 1961. Thus, the authors found no evidence suppor ting the dysgenic hypothesis. Rather the combined evidence points to a growing convergence across racial, socioeconomic, and ability-related segments of American society.