A Japanese robotics engineer has developed an innovative prosthesis for people missing hands due to an accident, illness or a congenital disability. The robotic hand picks up electrical signals traveling through the muscles, and uses artificial intelligence to move in accordance with the user's wishes. It's lighter and less expensive than conventional prostheses, and efforts are underway to put it into practical use. A smaller version made for a girl born without one hand allows her to perform complicated tasks, demonstrating how the technology can change people's lives.