The Human Spark | Running = Big Brains? | PBS

http://www.pbs.org/humanspark Alan Alda talks to scientist Dan Lieberman about why the human ability to run could be an important prerequisite for the evolution of our bigger brains -- and the emergence of our human spark. In "The Human Spark," Alan Alda visits dozens of scientists on three continents -- and even undergoes an examination of his own brain -- to find the answer to one question: What makes us human? Coming to PBS in January 2010. Learn more at http://www.pbs.org/humanspark