Researchers like Walter Neves and Hector Pucciarelli contributed detailed quantitative analyses of the Lagoa Santa cranial morphology, comparing the measurable characteristics of these ancient skulls not just to later Native American populations but to skeletal reference populations from around the world.

Their analyses found that the morphological characteristics of the Lagoa Santa skulls resembled, in statistical terms, the cranial profiles of populations from sub-Saharan Africa, Australia, and Melanesia — populations that had dispersed from Africa early in human prehistory and that retained certain ancestral morphological characteristics.

This finding led some researchers — including Neves and his collaborators — to propose what became known as the “two-population model” of American peopling: the idea that the Americas had been colonized by two distinct groups, with an earlier group carrying the morphological characteristics seen in Lagoa Santa and related material, and a later group with the different morphological profile seen in most later Native American populations.

The two-population model was not simply invented from nothing.