Testing the genetic hypothesis of group mean IQ differences in South Africa: Racial admixture and cross-situational consistency

Two predictions from the hereditarian model of group mean IQ differences are tested on a total sample of 1556 first-year university students in post-apartheid South Africa. The first prediction is that people of Mixed-Race average between the two parental populations. The second prediction is that the pattern of group means remains consistent over time and place. Data collated on South African university students given the Raven’s Standard and Advanced Progressive Matrices confirm the predictions. Combining the results for both versions of the test showed the rank order of group IQ means is East Asians, Whites, South Asians, Coloreds, and Blacks (IQs = 116, 113, 106, 103, and 98, respectively; Ns = 23, 398, 212, 36, and 887).