On the Origins of the Variations of Man

A discussion of Wallace's and Freud's theories of evolution and the impact of social and natural environment on the brain's development.
"In Wallace's pursuit of an origin of humankind, or more specifically the divergence of the various races, he comes across a rather interesting, strikingly intuitive idea: social and environmental conditions will act on the individual's mental capacities in ways which advance that individual's intelligence, thus “separating” or elevating it from the ranks of other tribes or clans."