“Perhaps nothing is more unexpected about our brains than that they are much smaller today than they were ten thousand or twelve thousand years ago, and by quite a lot. The average brain has shrunk from 1,500 cubic centimeters then to 1,350 cubic centimeters now. That’s equivalent to scooping out a portion of brain about the size of a tennis ball. That’s not at all easy to explain, because it happened all over the world at the same time, as if we agreed to reduce our brains by treaty. The common presumption is that our brains have simply become more efficient and able to pack more performance into a smaller space, rather like cell phones, which have grown more sophisticated as they have contracted in size. Bryson, Bill. The Body (p. 70). Knopf Doubleday Publishing Group. Kindle Edition. ”
