Humans as unfinished products

I recently read Steven Pinker's How the Mind Works.  I found it to be informative and thought provoking.  One of the thoughts which came to me is that humans are unfinished products.  Our brains are a mix of new and old.  I know that this is not entirely accurate since the old parts have evolved along with the new parts.  But the older parts of the brain have functions and neurochemistry which are still similar to what other animals have.  These brain elements influence and are influenced by the parts which are exclusively human.  As advanced as humans have become, the ways which our brains work are still developing.  The cognitive abilities mix and are sometimes overwritten by the more animalistic neurochemical responses.

I think that a danger with modern humans is that there is too little understanding of how our fairly new brain has some problems with the interactions of the parts.