In a new lab in its palatial Silicon Valley HQ, a red and black Sawyer robot arm (from the recently defunct company Rethink Robotics) is waving all over the place with a mechanical whine. It's supposed to casually move its hand to a spot in space to its right, but it goes up, up, up and way off course, then resets to its starting position. Then the arm goes right and gets pretty close to its destination. But then, agh!, it resets again before—maddeningly for those of us rooting for it—veering wildly off course again.

But, like a hare zigzagging back and forth to avoid a falcon, this robot's seeming madness is in fact a special brand of cleverness, one that Facebook thinks holds the key not only for better robots, but for developing better artificial intelligence. This robot, you see, is teaching itself to explore the world. And that, Facebook says, could one day lead to intelligent machines like telepresence robots.