Mayan and Chibchan Pre-Columbian Exchange Reinterpreting the Nature of Interaction Networks Within Middle America and Northern South America John W. Hoopes University of Kansas hoopes@ku.edu David Mora-Marín University of North Carolina-Chapel Hill davidmm@unc.edu Prepared for the 10 th European Maya Conference The Maya and Their Neighbours Universiteit Leiden en Rijksmuseum voor Volkenkunde Leiden 9-10 December 2005