The short answer?
Like any organ or tissues, our brains are subject to modification from environmental influences and selective forces. However, the evolution of our brains may not be headed in the direction you hope.
For a more detailed explanation I'd turn to the How Stuff Works article linked here.
"We might like to think that there's nothing but bigger and better things ahead of us, but British researchers have claimed that our brain is already operating at maximum capacity."
But the story doesn't quite end there. While roboticists at Carnegie Mellon University have concluded that "computers will surpass our processing abilities by 2030" this doesn't stop the human drive for cognitive improvement. At this stage in the very near future, we will be forced to make a heady choice:
Do we charge ahead and interface with computers in an attempt to control our own cognitive destinies?
Do we accept our natural place in the technologically advanced world we have created?
I'll leave you to think on that, but anticipate a follow up post next week with a potential third alternative...