For thousands of years, the way humans lived changed so slowly as to be imperceptible. That's no longer the case. Starry-eyed types who think of their autistic children as "indigo" or "crystal" children may wax poetic about autism being the next phase of human evolution, but recent scientific work lends a kernel of credence to that: autism is now thought to be one of the side effects of rapid changes to our brains that were evolutionarily necessary to cope with our rapidly changing world and circumstances.