This is a discussion on "The limits of human intelligence (or, why elves are evolutionarily implausible)" in the World Building forum.
First read about The Bell Curve:
The Bell Curve - Wikipedia, the free encyclopedia
You will see the human intelligence can go quite high. 2.5% of Humans have an IQ greater than 130, with a brain weight up to 1.400g. Neanderthals had brains as large as 1,700g, so humans have some room to grow intellectually, I am guessing way past an IQ of 200+.
Last edited by Robert Donnell; 6-17-12 at 3:43 PM.
In all honesty, I sort of groan whenever some expert or another comes out and says we have hit the limit of "X" in regards to humanity (whether X = population limits, civilization, intelligence, resources, wealth, innovation, etc) because people have been saying it for centuries in some form or another (Thomas Malthus is the most obvious example that springs to mind). Humans are pretty damn resourceful and we're pretty good at "outsourcing" things, such as computing power, in ways that transcend physical limitations.
But pessimism sells.