The computer-science prodigy has dedicated his life to weighty AI research. Now he’s also racing to make everyday Google products smarter. Google DeepMind CEO Demis Hassabis used to get some of his most fulfilling work done between midnight and 3 a.m. A self-described “nocturnal person,” the Londoner devoted the solitude of his overnight shift to catching up on scientific papers, coming up with new ideas, and just plain thinking.