Humor, like pornography, is famously difficult to define. We know it when we see it, but is there a way to figure out what we really find funnyand why? In this fascinating investigation into the science of humor and laughter, cognitive neuroscientist Scott Weems uncovers what’s happening in our heads when we giggle, guffaw, or double over with laughter. While we typically think of humor in terms of jokes or comic timing, in Ha! Weems proposes a provocative new model.