Unlike robots in the movies, most of today’s artificial intelligence (AI) cannot learn by itself; instead, it relies on intensive human feedback. Probably 90% of machine learning applications today are powered by supervised machine learning. This figure covers a wide range of use cases. An autonomous vehicle can drive you safely down the street because humans have spent thousands of hours telling it when its sensors are seeing a pedestrian, moving vehicle, lane marking, or other relevant object. Your in-home device knows what to do when you say “Turn up the volume” because humans have spent thousands of hours telling it how to interpret different commands. And your machine translation service can translate between languages because it has been trained on thousands (or maybe millions) of human-translated texts.