Are Human Brains Still Evolving? Brain Genes Show Signs of Selection

We humans are proud of our big brains, and rightly so. Averaging 1350 cubic centimeters (cc), the human brain is proportionally larger than that of any other animal. Its highly advanced cognitive powers have spurred us to create art, build cities, and send representatives of our species into space. Just why natural selection blessed us with these talents is poorly understood. But the fossil record and genetic studies clearly show that the evolution of higher cognition began sometime after the chimp and human lines split, some 5 million to 6 million years ago, and continued at least until the rise of modern humans, roughly 200,000 years ago.