Until recently, we thought of laughing, sneezing and hiccuping as ordinary human actions. But it turns out that these seemingly-mundane behaviors have a long evolutionary history. In fact, how we cough, laugh and hiccup says a lot about our psychology, and that of our ancestors.
Robert Provine is a professor of psychology and neuroscience at the University of Maryland, Baltimore. His new book is called "Curious Behavior: Yawning, Laughing, Hiccupping and Beyond."
Robert describes his work of "sidewalk neuroscience," or, as he writes, "a scientific approach to everyday behavior based on simple observations and demonstrations."