Are Americans becoming more or less alike? Trends in race, class, and ability differences in intelligence.

Abstract

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 outbreeding high-IQ parents. In this article, the authors examined the evidence for dysgenic trends by considering race-, class-, and ability-related 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 between the upper and lower thirds of social class groups have been decreasing slightly since 1932, and (c) Preliminary Scholastic Assessment Test-score differences between the top and bottom quartiles have been relatively stable since 1961. Thus, the authors found no evidence supporting the dysgenic hypothesis. Rather, the combined evidence points to a growing convergence across racial, socioeconomic, and ability-related segments of American society.

Skills Mismatch in the Labor Market

“…Others argue that a genuine decline can be inferred in the early 1970s, at least, when scores continued to drop despite the presumed increased selectivity of test takers resulting from declining college enrollments after the end of Vietnam draft deferments for college students (Koretz 1992). This conclusion is clouded by the fact that the shorter, Preliminary Scholastic Aptitude Test has been normed on representative samples of high school juniors and apparently shows no trend in either the mean or inter-quartile range since the early 1960s, and the variance seems to have declined during this period (Williams & Ceci 1997). However, some argue that there was an upward drift in the scaling of Preliminary Scholastic Aptitude Test scores over time that masks declining performance (Jones 1981).…”

An Institute for Social Capital: Enhancing Community Capacity Through Datasharing

“…The achievement gap between African American and other racial groups has been a perplexing problem for American educators for more than 40 years (Herrnstein and Murray 1994;Loehlin et al 1975;Lynn 1996;Neisser et al 1996;Williams and Ceci 1997). Recent educational reform (i.e., No Child Left Behind) has increased attention to this issue.…”

Race-Norming of Neuropsychological Tests

“…Asian American children as a grouping score 3-4 Full-Scale IQ points higher than White American children (Neisser et al 1996;Williams and Ceci 1997). Groupings of American Indian and Hispanic American children score 7-8 points below White American children on Verbal IQ, but have similar Performance IQ scores (Neisser et al 1996;Prifitera et al 1998;Puente and Salazar 1998).…”

“…It concluded: "Various explanations have been proposed, but none is generally accepted" (Neisser et al 1996, p. 94). The size of the African/White American difference in IQ scores may have shrunk in recent years to about 10 Full-Scale points (Dickens and Flynn 2006;Neisser et al 1996;Prifitera et al 1998;Williams and Ceci 1997). See Rushton and Jensen (2006) for rebuttal.…”