John Shea at Stony Brook University is one of the best stone toolmakers on the planet today, keeping alive the technologies used by our most ancient ancestors. As a paleoanthropologist, his interest is in recreating these once-ubiquitous tools to learn more about the early hominids who relied on them for survival. In this web-exclusive video, John Shea teaches Alan Alda some of the ins and outs of toolmaking… Do you think you can tell the difference between a stone that’s been worked by a person and one that’s been broken by nature?