Spearman's hypothesis and Amerindians: a meta-analysis

Spearman's hypothesis states that differences between groups on the subtests of an IQ battery are a function of the g loadings of these subtests, such that there are small differences between groups on subtests with low g loadings and large differences between groups on subtests with high g loadings, and it is confirmed in the large majority of studies. In this paper, we test Spearman's hypothesis, comparing Amerindians with Whites in the US and Canada. We carried out a meta-analysis based on 25 data points and a total N = 2706 Amerindians. Spearman's hypothesis was strongly confirmed with a mean r with a value of .62. We conclude that Spearman's hypothesis appears to be a more regular phenomenon than previously thought.