Altruism, the selfless concern for the well-being of others, is a core virtue in many societies and religions. But ever since Darwin wrote about cooperation and altruism, scientists have had a love/hate relationship with these behaviors. Warren Holmes, University of Oregon psychology professor, explores the paradox of cooperative behavior in "The Evolution of Cooperation and the Paradox of Altruism." It was the second talk in a UO lecture series celebrating the life and work of Charles Darwin given on Tuesday, Feb. 10 2009.