(Note: This interview first aired in early June.) "Eighty percent of success is showing up." Or so goes the old saying. But what do we really mean by this? And how does "showing up" in life -- or, if you prefer, routinely exhibiting "perseverance" -- relate to things like intellect, talent, drive, discipline, and so on? On this installment of ST, our guest is Dr. Angela Duckworth, a 2013 MacArthur Fellow and professor of psychology at the University of Pennsylvania who has advised the White House, the World Bank, and both NBA and NFL teams.