Forty years ago, legendary editor Walter Murch was working late one night on a film for Francis Ford Coppola called The Conversation (starring Gene Hackman). Like always, Murch was going back and forth through the footage, over and over again, looking to make the perfect cuts. Murch cuts intuitively, in real time. He never goes frame by frame. As the night went on, Murch started to notice something weird happening: Every time he made a cut, it seemed to line up perfectly with Gene Hackman blinking. “I began to get the sense that there was some collaboration going on between myself and…Gene Hackman,” Murch told Radiolab during an interview in 2009. What Murch had stumbled upon wasn’t just a useful editing technique; it was theory for why film editing works.