 So, if you've seen artificial intelligence in movies, it was probably trying to kill you. There's Skynet, Cylons, Ultron, Johnny Depp. The bad news is it's not just movies. A lot of smart people are legitimately worried about this, including the real-life Iron Man Elon Musk. We just can't predict what artificial intelligence will look like, or what it will want, or how it'll feel about humans. The good news is we're still pretty far from making it happen. Many theories about AI were based on the assumption that intelligence was pretty much located in the brain, and they had a specific type of brain in mind, a computational brain. It's like a computer chip that processed all these symbols that represent experience. So you have a symbol for tree, a symbol for bat, a symbol for the letter Q, and when you see those, your brain processes the data and you get experience. But we've learned a lot more about the brain since then, and the metaphor has started to break down. The brain is squishy and unpredictable, and it just doesn't map well to the logic of computers. You can't just stick the Intel chip from your laptop into a cyborg suit, and presto, you get something that looks like your brother or sister. So we can't code in human consciousness from the top down. But what if we tried from the ground up? The theory here is that consciousness arises out of a dynamic, complex interaction between a body and the world. So the program needs a body, and that body needs a world full of interesting stuff like trees and grass, and that's still tricky to do in the physical world. The body's this insanely complex system that we're only starting to understand. But researchers can attack smaller problems like image recognition by letting programs explore the web. A couple years ago, Google set loose 16,000 independent programs to sort through a mess of raw data with no clues about what it meant or what it had in common. After looking at 10 million YouTube thumbnails, the system finally figured out how to recognize cats. Even then, they were only right about 70% of the time. That approach might never create intelligence like ours, but along the way it's turned up a lot of really important research from roboticists, psychologists, and philosophers. Even if we can't create computers that think, we can use the same techniques to create computers that see and talk and reason. And more importantly, we can find out a lot more about what it means to be human.