2015 Hallam L. Movius, Jr. lecture and reception with Stanley H. Ambrose, Professor of Anthropology, University of Illinois at Urbana-Champaign The eruption of the Mount Toba supervolcano in the Indonesian island of Sumatra 74,000 years ago brought about an era of severe environmental degradation that decimated populations of Neanderthals and modern humans. Archaeological evidence suggests that modern humans survived this era by creating cooperative intergroup social networks and behaving like tribes. Neanderthals, on the other hand, behaved more like primate troops, living in small, closed territories with limited intergroup interaction. Stanley Ambrose will discuss the behaviors that contributed to the competitive advantage of modern humans and the demise of Neanderthals. Recorded March 12, 2015.