Microsoft CEO aims to build artificial intelligence capable of empathy, emotion

Cortana, Microsoft's answer to Apple's Siri, is already become more intelligent every day, Nadella said, echoing his recent comments in Slate, where he argued that humans and machines will work together, not against each other. "With all the abundance we have of computers and computing, what is scarce is human attention and time," Nadella said. "So having the personal digital assistant really helps me regain my time -- empowers me to get more out of every moment of my life." Nadella spoke alongside Walter Isaacson, CEO of the Aspen Institute and author of "Steve Jobs," at the Aspen Ideas Festival in Colorado, where speakers covered broad topics like the role of machines in policy and the future of Mars. The interview coincided with the announcement of Nadella's new book, "Hit Refresh," that will focus on the future of intelligent machines.