I believe in the blank slate! | Gene Expression | Discover Magazine:
'via Blog this'
Above is a link to an article that hits the sweet spot with regards to the complexity of how both genes and environmentally transmitted cultural information shape what we are as humans. In this case it's a proposal that genetically modern humans spread out from Africa and coexisted with or inhabited areas in Eurasia that bordered regions occupied by older lineages like H. neanderthalensis and the recently discovered denisovans. Those same modern humans held genes that conferred latent potentials, which were finally realized with the arrival of some sort of cultural revolution that enabled homo sapiens to displace or assimilate the kin that it had previously bumped up against.
As I've written about previously, my pet theory for a cultural influence that greatly increased the complexity of the brain's wiring in individuals is syntactical spoken language. Learning a grammatically structured communications scheme significantly alters a human brain. So much so, that it is clinically recognized, with individuals unfortunate enough never to have learned a language during the youthful brain's super plasticity phases between ages two and sixteen expressing lifetime deficits in abstract reasoning.
Words and the ability to order them into sentences that carry larger meta meanings likely offered an entirely new avenue for internally manipulating concepts in a species that had previously been a visual thinker. The genes involved in the latency were probably in part those that set the stage for the development of the semantic memory subsystem, construct the speech-generating Broca's region in the brain, and those that enable complex associative connections in the neocortex.