High integration of brain networks seems to be associated with high IQ. ‘You pay a price for intelligence. Becoming smarter means improving connections between different brain areas but this runs into tight limits on energy, along with space for the wiring.’
I gots lotsa room fer brain growin
I agree , Suzan's Blackmore point of view on memetic is very interesting at that level. See on TED talk.
No doubt a human/computer interface that will expand our intellectual prowess is almost inevitable in the near future. However, from a strickly biological and evolutionary position expanded intellectual progress has for the most part peaked.
For larger cranial capacity female anatomy would also have to change, as the current cranial size is at the upper extreme for passage through the birth canal (a reality I'm confident any mother can attest to). Larger headed babies will result in some really pissed off mommies - at the very least.
Interesting enough there is a philosopher that talks about human/technology interface as a part of our cognition. His book Supersizing the Mind was a difficult read and I won't pretend to understand all of it, but taken this way technology has been a part of our evolution just as much as anything else.
"Clark is perhaps most famous for his defence of the hypothesis of the Extended mind. According to Clark, the dynamic loops through which mind and world interact are not merely instrumental. The cycle of activity that runs from brain through body and world and back again actually constitutes cognition. The mind, on this account, is not bounded by the biological organism but extends into the environment of that organism." (wikipedia on Andy Clark.)
Available energy is only half the problem, the other half is in the way the brain is connected. It is true that we don't use the whole of our brains now, however, the brain isn't just used for thought, it also controls bodily functions such as heartbeat. If we were to somehow develop a way to use the entire human brain for thinking, that means that we would also have to find a way to consciously regulate our heart rate.
A common belief is that the more we learn, the more we forget. In a way that does make logical sense. The human brain is like a computer, it only has so much storage space for data. Perhaps our brains are constantly replacing old information with new information. If that's the case, then modern technology may also prove an answer for that too, by giving us the ability to store at least a portion of our intellect outside the brain and even outside the body.