Book excerpt: Have you ever felt a sudden rush of recognition that you've been in a place before? What causes a déjà vu? Why do dogs look like their owners? What's up with insect swarms? What's the science behind showing your tongue? Do you keep drier by walking or running through a rainstorm? In this updated and expanded edition of The Science of Everyday Life, bestselling author Jay Ingram explains these and many more weird and fascinating mysteries.