Broca was one of the first anthropologists engaged in comparative anatomy of primates and humans. Comparing then dominant craniometry based measures of intelligence as well as other factors such as relative forearm-to-arm length, he proposed that Negroes were an intermediate form between apes and Europeans. The renowned evolutionary biologist Stephen Jay Gould criticized Broca and his contemporaries of being engaged in "scientific racism" when conducting their research. Basing their work on biological determinism, and ""a priori" expectations" that "social and economic differences between human groups—primarily races, classes, and sexes—arise from inherited, inborn distinctions and that society, in this sense, is an accurate reflection of biology."