Why not, indeed. *Did you ever run across McClean's triune theory
of the evolution of the human brain? *Boiled down, it says that
the human brain is evolved on top of (rather than in place of)
the old reptilian brain, and that it consists of the old
reptilian brain (which controls basic functions necessary to
survival, aggression), the old mammalian brain (the limbic
system, responsible for emotional regulation and more complex
behaviors) and new mammalian brain, the cerebral cortex,
responsible for "higher functions" such as planning and language.
* Each of these functions somewhat on its own, but is highly
interconnected with the other parts.

Interesting. This article would seem to give some credence to that
theory...
http://www.newscientist.com/article/...obstacles.html