Google, Facebook and other tech companies race to develop artificial intelligence

The latest Silicon Valley arms race is a contest to build the best artificial brains.

Facebook, Google and other leading tech companies are jockeying to hire top scientists in the field of artificial intelligence, while spending heavily on a quest to make computers think more like people. They're not building humanoid robots -- not yet, anyway. But a number of tech giants and startups are trying to build computer systems that understand what you want, perhaps before you knew you wanted it.