Phobias can arise from all sorts of lurking dangers, like venomous snakes. But holes? Is trypophobia really a thing? Find out why a person might fear an array of innocent holes and the role social contagion could play.
Glass, Cold, Sound, Clean, Time and Light. Just a random collection of items in the physical world, right? Not in the hands of science journalist Steven Johnson, who weaves a revelatory tale of technological wonders in his new book and PBS series, "How We Got to Now: Six Innovations That Made the Modern World." Join Julie and Robert for an interview with the man behind the book and series.