A Google program can pass as a human on the phone. Should it be required to tell people it's a machine?

Google's artificial-intelligence assistant sounds almost exactly like a human when it calls the salon to book a woman's hair appointment. It responds to questions, negotiates timing and thanks the receptionist for her help. It even says "um" and "mm-hmm." What it doesn't say, however, is that it's a machine -- and the receptionist doesn't show any sign that she can tell. Google's unveiling on Tuesday of Duplex -- an automated voice assistant that can book restaurant reservations, check opening hours and accomplish other tasks over the phone -- has thrown a spotlight on how advanced AI can now carry on conversations that are so lifelike that even a human listener can be fooled. The technology, debuted at Google's I/O developer conference, could be a huge convenience for anyone who hates picking up the phone.