Originally Posted by
kanamit 
All mammals have a Neocortex, but it is far more prominent in apes, and certainly humans. Nevertheless, the primal brain, while not particularly intelligent in and of itself, is very good at its job (survival), and very persistent in achieving that goal. It just gets confused and ends up chasing the wrong stuff because all hedonic drugs release the same chemicals that it associates with survival, except in much larger quantities.