Spearman's hypothesis tested comparing Libyan adults with various other groups of adults on the items of the Standard Progressive Matrices

Spearman's hypothesis tested at the level of items states that differences between 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 groups on items with low g loadings and large differences between groups on items with high g loadings, and it has been confirmed in a limited number of studies. In this paper, we tested Spearman's hypothesis, comparing groups of Libyan university students and adults with comparable groups from South Africa, Spain, and Russia, and a group of Roma (Gypsies) from Serbia (total N = 844). The analyses were carried out on comparisons between the Libyans and the other groups. Spearman's hypothesis was strongly confirmed with a mean weighted r with a value of .73. We conclude that Spearman's hypothesis tested at the item level appears to be a more regular phenomenon than previously thought.