Last summer, a sign appeared on the door to a stuffy, windowless room at the office of Manhattan artificial intelligence startup Clarifai. “Chamber of secrets,” it read, according to three people who saw it. The notice was a joking reference to how the small team working inside was not permitted to discuss its work with others at Clarifai.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.