Originally Posted by Oriphiel

First of all, there aren't multiple races of humanity. Humanity itself is a race. And while all of the sub-races that it is split up into do have varying attributes as they've adapted to various environments, the truth is that these sub-races haven't existed on their own for long enough to be drastically different from each other. The only real differences you'll find are in skin pigmentation and bone structure, as well as different genetic traits and slight changes in average organ sizes (such as the lungs), but never intelligence.

Think about it. If every group of humanity is surviving on their own, and survival of the fittest is in effect, why would one group become less intelligent than the others? Losing intelligence is a sure-fire way to get killed off before your genes can have a chance to spread. Makes no evolutionary sense, and every valid study into the subject has determined that no race is inherently "smarter" than the others. Now stop all of this racist drivel and let it be.

Check out "The Race Myth: Why We Pretend Race Exists in America" by Joseph Graves. It might answer some questions for you.