Curiosity. Obsessions. Serial. Hermaphroditic snails. The “shape” of a radio show. When you sit down with Jad Abumrad and Robert Krulwich, creators and cohosts of the innovative, hugely popular podcast Radiolab, you never know where the conversation will lead.As millions of listeners know, Abumrad and Krulwich regularly blur the boundaries between storytelling, science, and philosophy in their sound-rich show, which airs on more than 450 NPR stations around the country. Hold That Thought’s Claire Navarro and Rebecca King were thrilled to meet and interview both Abumrad and Krulwich earlier this year, when the duo visited Washington University in St. Louis as the culmination of a week-long celebration of curiosity and the liberal arts.