Jensen Effects and African/Coloured/Indian/White differences on Raven's Standard Progressive Matrices in South Africa

Differential Item Functioning on Raven’s SPM+ Amongst Two Convenience Samples of Yakuts and Russians

National IQ estimates are based on psychometric measurements carried out in a variety of cultural contexts and are often obtained from Raven’s Progressive Matrices tests. In a series of studies, J. Philippe Rushton et al. have argued that these tests are not biased with respect to ethnicity or race. Critics claimed their methods were inappropriate and suggested differential item functioning (DIF) analysis as a more suitable alternative. In the present study, we conduct a DIF analysis on Raven’s Standard Progressive Matrices Plus (SPM+) tests administered to convenience samples of Yakuts and ethnic Russians. The Yakuts scored lower than the Russians by 4.8 IQ points, a difference that can be attributed to the selectiveness of the Russian sample. Data from the Yakut (n = 518) and Russian (n = 956) samples were analyzed for DIF using logistic regression. Although items B9, B10, B11, B12, and C11 were identified as having uniform DIF, all of these DIF effects can be regarded as negligible (R2 <0.13). This is consistent with Rushton et al.’s arguments that the Raven’s Progressive Matrices tests are ethnically unbiased.

Spearman's hypothesis tested comparing Korean young adults with various other groups of young adults on the items of the Advanced Progressive Matrices

Spearman's hypothesis tested at the subtest level of an IQ battery states that differences between races on the subtests of an IQ battery are a function of the g loadings of these subtests, such that there are small differences between races on subtests with low g loadings and large differences between races on subtests with high g loadings. Jensen (1998) stated that Spearman's hypothesis is a law-like phenomenon. It has also been confirmed many times at the level of items of the Raven's Progressive Matrices. This study hypothesizes that with concern to Spearman's hypothesis, subtests and items function in fundamentally the same way, and tested whether Spearman's hypothesis is confirmed at the item level for White-East Asian comparisons. A group of Korean young adults (N=205) was compared with other groups of young adults from Canada, the US, Russia, Peru and South Africa (total N=4770) who took the Advanced Progressive Matrices. Spearman's hypothesis was strongly confirmed with a sample-size-weighted r with a value of 0.63. Computing the g loadings of the items of the Raven with either the Raven-g or the Wechsler-g led to the same conclusions. Tests of Spearman's hypothesis yielded less-strong outcomes when the 36-item Advanced Progressive Matrices were used than when the 60-item Standard Progressive Matrices were used. There is a substantial correlation between sample size and the outcome of Spearman's hypothesis. So, all four hypotheses were confirmed, showing that a part of the subtest-level nomological net replicates at the item level, strengthening the position that, with concern to Spearman's hypothesis, subtests and items function fundamentally the same. It is concluded that Spearman's hypothesis is still a law-like phenomenon. Detailed suggestions for follow-up research are made.

SPEARMAN'S HYPOTHESIS TESTED COMPARING SAUDI ARABIAN CHILDREN AND ADOLESCENTS WITH VARIOUS OTHER GROUPS OF CHILDREN AND ADOLESCENTS ON THE ITEMS OF THE STANDARD PROGRESSIVE MATRICES

Spearman's hypothesis tested at the level of items states that differences between ethnic groups on the items of an IQ test are a function of the g loadings of these items, such that there are small differences between ethnic groups on items with low g loadings and large differences between ethnic groups on items with high g loadings; this has been confirmed in a limited number of studies. In this paper, Spearman's hypothesis was tested, comparing a group of Saudi children and adolescents (N=3209) with other groups of children and adolescents from Denmark, Cyprus, Croatia, Bosnia, South Africa, Estonia, Ukraine, Ireland, Russia and Chile (total N=9333). The analyses were carried out on twelve comparisons between the Saudi Arabian children and the other children. Spearman's hypothesis was confirmed less strongly than in other large-scale studies with a mean weighted r value of 0.44. The relevance of these findings for the discussion on the causes of group differences is discussed.