It’s been almost 50 years now that the famous study of Willerman et al. (1974) has been published. This study is regularly cited as one of the most convincing evidence against the hereditarian hypothesis, despite strong emphasis by hereditarians on the failure of experimental efforts to raise IQ (more specifically, g) and population differences magnifying during adolescence or adulthood due to increasing heritability with age (Jensen, 1998, pp. 333-344, 359, 474; See Malloy  for a case of a stability model with respect to the Black-White gap). Caution about this study is now vindicated. The data used by Willerman also revealed a pattern: the IQ deficits related to having a Black mother seem to vanish over time (Hu, 2022). Continue reading
Given the central role that testing plays in the American educational system, most datasets that we have on racial and ethnic differences in cognitive ability include only children, adolescents, or young adults. Most of the economic and social effects of cognitive differences are, however, produced by the working age population, so it would be useful to have test scores from older adults as well. The PIAAC survey of adult skills conducted by the OECD provides excellent data for this purpose. Continue reading
Kirkegaard, E. O. W. & Fuerst, J. (2016). Inequality in the United States: Ethnicity, Racial Admixture and Environmental Causes. Mankind Quarterly 56(4).
Previously, we looked at the association between overall state-level biogeographic ancestry (BGA) and overall state-level outcomes. It was found that European BGA relative to African and Amerindian BGA was associated with better outcomes. In this paper, the analysis is extended by looking at the state-level ancestry-outcome associations individually for black and Hispanic self-identified race-ethnicity (SIRE) groups. General socioeconomic factor (S) scores were calculated for US states by SIRE groups based on three indicators. The S factor loadings were generally stable across subgroup analyses and the factor scores were stable across factor analytic extraction methods (for the latter, almost all r’s ≈ 1). For Whites, Blacks and Hispanics, there were strong correlations between cognitive ability scores and S factor scores across states (r = .55 to .78; N = 28-50). This pattern also held when all data were analyzed together (r = .86, N = 115). Furthermore, the size of the Hispanic-White and Black-White S and cognitive ability gaps strongly correlated across states (r = .62 to .69; N = 36-37). Lastly, parasite prevalence did not plausibly explain SIRE gaps in cognitive ability because gaps were smaller in more parasite-rich states (combined analysis r = -.17, N = 91). We found that climatic and geospatial variables did not correlate strongly with cognitive ability and S scores when scores were decomposed by SIRE group, but did so at the total state level, even after statistically controlling for SIRE composition.
Published: September 15, 2014
John Fuerst 
Abstract: The authors conducted a meta-analysis of interactions between behavioral genetic variance components (ACE) and race/ethnicity for cognitive ability. The differences between the variance components for Black and White Americans were small, despite the large average test score differences. More substantial differences were found between Hispanics and non-Hispanic Whites, though results were based on only two studies. A biometric re-analysis of the CNLSY survey was then conducted and new meta-analytic results were provided. Results were discussed in light of the bio-ecological model which proposes that when the scores of subgroups are environmentally depressed, heritabilities will be likewise.
Keywords: Race, Ethnicity, Heritability, IQ, Environment, ACE model, bio-ecological model
An early version of this paper was posted on June 25th. The paper has since been extensively edited and corrected and, subsequently, published at Open Differential Psychology on July 25/26th, 2014. The paper and data files can be found here at the Open Differential Psychology site.
Cognitive ability differences between racial/ethnic groups are of interest to social scientists and policy makers. In many discussions of group differences, racial/ethnic groups are treated as monolithic wholes. However, subpopulations within these broad categories need not perform as the racial/ethnic groups do on average. Such subpopulation differences potentially have theoretical import when it comes to causal explanations of racial/ethnic differentials. As no meta-analysis has previously been conducted on the topic, we investigated the magnitude of racial/ethnic differences by migrant generations (first, second, and third+). We conducted an exploratory meta-analysis using 18 samples for which we were able to decompose scores by sociologically defined race/ethnicity and immigrant generation. For Blacks and Whites of the same generation, the first, second, and third+ generation B/W d-values were 0.79, 0.79, and 1.00. For Hispanics and Whites of the same generation, the first, second, and third+ generation H/W d-values were 0.76, 0.67, and 0.57. For Asians and Whites of the same generation, the first, second, and third+ generation d-values were -0.08, -0.21, and 0.00. Relative to third+ generation Whites, the average d-values were 0.99, 0.84, and 1.00 for first, second, and third+ generation Black individuals, 1.04, 0.71, and 0.57 for first, second, and third+ generation Hispanic individuals, 0.16, -0.18, and -0.01 for first, second, and third+ generation Asian individuals, and 0.24 and 0.04 for first and second generation Whites.
Keywords: Immigrants, group differences, race, ethnicity, aptitude, National IQ
The strong heritability of IQ is well established for white populations in America, with dozens of studies confirming the basic findings. When it comes to heritability in non-whites, the handful of studies that exist (see Jensen 1998, p. 446ff.; Rowe et al. 1999; Guo & Stearns 2002; cf. John’s recent post) do not allow us to conclude that heritability is lower (or higher) in non-white Americans than it is among white Americans, but there is a sore need for more research.
To diminish this uncertainty, we compared the heritability of several different cognitive abilities in whites, blacks, and Hispanics in the CNLSY sample. The sample, which consists of the children of the mothers who are part of the NLSY79 study, includes the results of various ability tests administered between ages 3 and 13. Continue reading
The Commonwealth of Puerto Rico is a Spanish-speaking territory of the United States. Puerto Ricans are United States citizens—they can freely migrate between the island and the states, join the military, or even run for president. But they can’t vote for president, because the territory is not a U.S. state. In three referendums from 1967 to 1998, Puerto Rican voters rejected both political independence and U.S. statehood. However, in November 2012 a solid majority (61.3%) voted in favor of statehood. This kind of political nudging could quite possibly result in Puerto Rico becoming the 51st U.S. state … but only Congress and the president have authority over the matter, and analysts agree that approval is unlikely. This particular referendum also left off the option traditionally most favored by Puerto Ricans: continued commonwealth status. Many islanders appear to feel that statehood offers few additional benefits over citizenship; a majority of Puerto Ricans already live on the U.S. mainland (5 million vs. 3.7 million).
From the earliest days of intelligence testing, social scientists have taken a special interest in U.S. Hispanics. Proportionate to their numbers, it’s possible that more tests have been given to Hispanics than to blacks. But this special attention has also lacked focus. African-American test results have been subject to meticulous cataloging, synthesis and analysis (Shuey, 1966; Jensen, 1998; Jencks & Phillips, 1998) leading to somewhat of a consensus on the size and shape of the black-white cognitive performance gap. Yet there has not been a similar effort to process the disparate and voluminous literature on the abilities of U.S. Hispanics. Therefore there is less knowledge and consensus about the historical and contemporary test performance of Hispanic minorities.
Most of the U.S. Hispanic population is Mexican American (63%). Puerto Ricans are the second largest Hispanic minority (9.2% … or 15.3% including the Commonwealth). This post represents the first effort to comprehensively summarize the abilities of one of these two important American minority groups. Here I describe and analyze the results from over 70 studies that have measured the abilities of Puerto Ricans.
Much has been written about social class differences in the heritability of cognitive ability, little about racial and ethnic differences. I will leave a review of the issue, a discussion of our meta-analytic results, and a report of our technically complex CNLSY ACE x race/ethnicity analysis to my more loquacious (and apt) colleagues. Here I present results based on the (effectively) small NLSY79 kinship sample.
In digit span tests, the respondents are asked to repeat a string of digits. There are two variants of the test, forward digit span (FDS) and backward digit span (BDS). In FDS, the digits are repeated in the order of their presentation, while in BDS they must be repeated in the reverse order. The largest number of digits that a person can repeat without error is his or her forward or backward digit span.
It is well-established that the black-white gap is substantially larger on BDS than FSD (see references in The g Factor by Jensen, p. 405, Note 22; see also my recent analysis of the DAS-II). However, replication is always good, so I analyzed black-white differences in the CNLSY sample, which contains FDS and BDS scores for relatively large samples of black and white children. Additionally, I compared the digit span performance of Hispanic American children to that of blacks and whites. Continue reading
According to Spearman’s hypothesis, the magnitude of the black-white gap on a given cognitive ability test is primarily determined by the test’s g loading. Tests that are better measures of g are associated with larger gaps.
The Differential Ability Scales, Second Edition, or the DAS-II, is an IQ test for assessing children and adolescents. It comprises a total of 21 subtests, although in the present analysis only 13 subtests are used, because not all tests are administered across age groups. I will use the method of correlated vectors (MCV) to test whether g loadings are correlated with mean racial differences on the DAS-II subtests. In addition to the black-white gap, I will also investigate if the test performance of Asians and Hispanics is predicted by g loadings. Continue reading