We're left wondering, what would happen if you were to treat a good idea like an infectious disease? Could you trace it back to one individual, and one flash of insight? Jon Mooallem tells us about his quest to track down the origin of the high five--a story that starts with one of the most celebratory gestures imaginable ... and ends with a choice that pits a happy ending against a more complicated reality. Lutha Davis, Greg Harrell-Edge, Nolan Smith, and Kathy Gregory all weigh in with competing explanations. And Tim Hemmes and Katie Schaffer tell a moving story about the power of their very own first high five.

All this leaves us with an inevitable, but unsettling question. A question that Jonnie Hughes helps answer with a broadminded look at the history of the cowboy hat.

Read More:

Jonnie Hughes, The Origin of Teepees

Debbie Henderson, Hat Talk

Tim Hemmes and Katie Schaffer give each other a high five (listen before you watch the video):