The urge to eat clay, starch, ice and chalk has been a phenomenon among humans, particularly women, for a very long time. Nutritional scientist Sera Young discussed her new book, "Craving Earth: Understanding Pica--the Urge to Eat Clay, Starch, Ice, and Chalk," November 3, 2011 as part of Mann Library's Chats in the Stacks series.

Dr. Young's research seeks to understand why some people engage in this curious behavior and to shed light on the properties possessed by non-food substances associated with pica.