This hour we talk to Joe Navarro, author of Dangerous Personalities: An FBI Profiler Shows How to Identify and Protect Yourself from Harmful People (Rodale Books, October 2014). Navarro takes us through the four personality types we should watch out for—and assuages any fears that the Modern Notion staff is riddled with narcissists. Contributing editor Erin Blakemore talks about Lewis and Clark’s poop, and why it’s so helpful to archaeologists. And from KALW in the Bay Area, we hear the story of a girl who becomes enraged by certain sounds.