He critiqued certain conventionally-held aspects of anthropology, such as craniometry and racialist interpretations of human physical data. He was the first to point out how racial typologies failed to account for the successes of those of mixed race as well as one of the first to state an accurate scientific basis for skin pigmentation.
He examined certain established ideas within anthropology, such as craniometry and racial interpretations based on physical characteristics. He was among the first to demonstrate that racial classifications failed to include people of mixed ancestry, and he was one of the earliest to present a scientifically valid explanation for skin coloration.